SONAR-6799 SONAR-6232 compute engine logs

- add WS api/ce/logs
- add boolean field 'logs' to the responses of the WS that return tasks
- purge log files (max nb of files per project can be configured)

41 files changed, 1608 insertions, 56 deletions

diff --git a/server/sonar-process/src/main/java/org/sonar/process/LogbackHelper.java b/server/sonar-process/src/main/java/org/sonar/process/LogbackHelper.java
index 6afcbfa1738..0d5d3551872 100644
--- a/server/sonar-process/src/main/java/org/sonar/process/LogbackHelper.java
+++ b/server/sonar-process/src/main/java/org/sonar/process/LogbackHelper.java
@@ -29,16 +29,17 @@ import ch.qos.logback.classic.spi.LoggerContextListener;
 import ch.qos.logback.core.ConsoleAppender;
 import ch.qos.logback.core.Context;
 import ch.qos.logback.core.FileAppender;
+import ch.qos.logback.core.filter.Filter;
 import ch.qos.logback.core.joran.spi.JoranException;
 import ch.qos.logback.core.rolling.FixedWindowRollingPolicy;
 import ch.qos.logback.core.rolling.RollingFileAppender;
 import ch.qos.logback.core.rolling.SizeBasedTriggeringPolicy;
 import ch.qos.logback.core.rolling.TimeBasedRollingPolicy;
+import java.io.File;
+import javax.annotation.Nullable;
 import org.apache.commons.lang.StringUtils;
 import org.slf4j.LoggerFactory;
 
-import java.io.File;
-
 /**
  * Helps to configure Logback in a programmatic way, without using XML.
  */
@@ -72,7 +73,7 @@ public class LogbackHelper {
     return propagator;
   }
 
-  public ConsoleAppender newConsoleAppender(Context loggerContext, String name, String pattern) {
+  public ConsoleAppender newConsoleAppender(Context loggerContext, String name, String pattern, @Nullable Filter filter) {
     PatternLayoutEncoder consoleEncoder = new PatternLayoutEncoder();
     consoleEncoder.setContext(loggerContext);
     consoleEncoder.setPattern(pattern);
@@ -82,6 +83,9 @@ public class LogbackHelper {
     consoleAppender.setEncoder(consoleEncoder);
     consoleAppender.setName(name);
     consoleAppender.setTarget("System.out");
+    if (filter != null) {
+      consoleAppender.addFilter(filter);
+    }
     consoleAppender.start();
     return consoleAppender;
   }
diff --git a/server/sonar-process/src/test/java/org/sonar/process/LogbackHelperTest.java b/server/sonar-process/src/test/java/org/sonar/process/LogbackHelperTest.java
index 5d63c90350c..1cd17d936bf 100644
--- a/server/sonar-process/src/test/java/org/sonar/process/LogbackHelperTest.java
+++ b/server/sonar-process/src/test/java/org/sonar/process/LogbackHelperTest.java
@@ -27,21 +27,22 @@ import ch.qos.logback.classic.spi.LoggerContextListener;
 import ch.qos.logback.core.Appender;
 import ch.qos.logback.core.ConsoleAppender;
 import ch.qos.logback.core.FileAppender;
+import ch.qos.logback.core.filter.Filter;
 import ch.qos.logback.core.rolling.FixedWindowRollingPolicy;
 import ch.qos.logback.core.rolling.RollingFileAppender;
 import ch.qos.logback.core.rolling.SizeBasedTriggeringPolicy;
 import ch.qos.logback.core.rolling.TimeBasedRollingPolicy;
+import java.io.File;
+import java.util.Properties;
 import org.junit.AfterClass;
 import org.junit.Before;
 import org.junit.Rule;
 import org.junit.Test;
 import org.junit.rules.TemporaryFolder;
 
-import java.io.File;
-import java.util.Properties;
-
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.junit.Assert.fail;
+import static org.mockito.Mockito.mock;
 
 public class LogbackHelperTest {
 
@@ -81,12 +82,22 @@ public class LogbackHelperTest {
   @Test
   public void newConsoleAppender() {
     LoggerContext ctx = underTest.getRootContext();
-    ConsoleAppender<?> appender = underTest.newConsoleAppender(ctx, "MY_APPENDER", "%msg%n");
+    ConsoleAppender<?> appender = underTest.newConsoleAppender(ctx, "MY_APPENDER", "%msg%n", null);
 
     assertThat(appender.getName()).isEqualTo("MY_APPENDER");
     assertThat(appender.getContext()).isSameAs(ctx);
     assertThat(appender.isStarted()).isTrue();
     assertThat(((PatternLayoutEncoder) appender.getEncoder()).getPattern()).isEqualTo("%msg%n");
+    assertThat(appender.getCopyOfAttachedFiltersList()).isEmpty();
+  }
+
+  @Test
+  public void newConsoleAppender_with_filter() {
+    Filter filter = mock(Filter.class);
+    LoggerContext ctx = underTest.getRootContext();
+    ConsoleAppender<?> appender = underTest.newConsoleAppender(ctx, "MY_APPENDER", "%msg%n", filter);
+
+    assertThat(appender.getCopyOfAttachedFiltersList()).containsOnly(filter);
   }
 
   @Test
diff --git a/server/sonar-search/src/main/java/org/sonar/search/SearchLogging.java b/server/sonar-search/src/main/java/org/sonar/search/SearchLogging.java
index bb031f8407f..42c49f5c4ad 100644
--- a/server/sonar-search/src/main/java/org/sonar/search/SearchLogging.java
+++ b/server/sonar-search/src/main/java/org/sonar/search/SearchLogging.java
@@ -24,7 +24,6 @@ import ch.qos.logback.classic.Logger;
 import ch.qos.logback.classic.LoggerContext;
 import ch.qos.logback.classic.spi.ILoggingEvent;
 import ch.qos.logback.core.ConsoleAppender;
-
 import org.sonar.process.LogbackHelper;
 
 public class SearchLogging {
@@ -37,7 +36,7 @@ public class SearchLogging {
     LoggerContext ctx = helper.getRootContext();
     ctx.reset();
 
-    ConsoleAppender<ILoggingEvent> consoleAppender = helper.newConsoleAppender(ctx, "CONSOLE", LOG_FORMAT);
+    ConsoleAppender<ILoggingEvent> consoleAppender = helper.newConsoleAppender(ctx, "CONSOLE", LOG_FORMAT, null);
     Logger rootLogger = helper.configureLogger(ctx, Logger.ROOT_LOGGER_NAME, Level.INFO);
     rootLogger.addAppender(consoleAppender);
     return ctx;
diff --git a/server/sonar-server/src/main/java/org/sonar/server/app/WebLogging.java b/server/sonar-server/src/main/java/org/sonar/server/app/WebLogging.java
index a3887f1bd59..7fda6bd2099 100644
--- a/server/sonar-server/src/main/java/org/sonar/server/app/WebLogging.java
+++ b/server/sonar-server/src/main/java/org/sonar/server/app/WebLogging.java
@@ -24,13 +24,13 @@ import ch.qos.logback.classic.Logger;
 import ch.qos.logback.classic.LoggerContext;
 import ch.qos.logback.classic.spi.ILoggingEvent;
 import ch.qos.logback.core.ConsoleAppender;
-
+import java.util.logging.LogManager;
 import org.slf4j.bridge.SLF4JBridgeHandler;
 import org.sonar.api.utils.MessageException;
 import org.sonar.process.LogbackHelper;
 import org.sonar.process.Props;
-
-import java.util.logging.LogManager;
+import org.sonar.server.computation.log.CeLogDenyFilter;
+import org.sonar.server.computation.log.CeLogging;
 
 /**
  * Configure logback for web server process. Logs must be written to console, which is
@@ -48,7 +48,7 @@ class WebLogging {
     ctx.reset();
 
     helper.enableJulChangePropagation(ctx);
-    configureAppender(ctx);
+    configureAppender(ctx, props);
     configureLevels(ctx, props);
 
     // Configure java.util.logging, used by Tomcat, in order to forward to slf4j
@@ -57,9 +57,11 @@ class WebLogging {
     return ctx;
   }
 
-  private void configureAppender(LoggerContext ctx) {
-    ConsoleAppender<ILoggingEvent> consoleAppender = helper.newConsoleAppender(ctx, "CONSOLE", LOG_FORMAT);
+  private void configureAppender(LoggerContext ctx, Props props) {
+    ConsoleAppender<ILoggingEvent> consoleAppender = helper.newConsoleAppender(ctx, "CONSOLE", LOG_FORMAT, new CeLogDenyFilter<ILoggingEvent>());
     ctx.getLogger(Logger.ROOT_LOGGER_NAME).addAppender(consoleAppender);
+    ctx.getLogger(Logger.ROOT_LOGGER_NAME).addAppender(CeLogging.createAppenderConfiguration(ctx, props));
+
   }
 
   private void configureLevels(LoggerContext ctx, Props props) {
diff --git a/server/sonar-server/src/main/java/org/sonar/server/computation/CePropertyDefinitions.java b/server/sonar-server/src/main/java/org/sonar/server/computation/CePropertyDefinitions.java
new file mode 100644
index 00000000000..6ccf89f31fd
--- /dev/null
+++ b/server/sonar-server/src/main/java/org/sonar/server/computation/CePropertyDefinitions.java
@@ -0,0 +1,45 @@
+/*
+ * SonarQube, open source software quality management tool.
+ * Copyright (C) 2008-2014 SonarSource
+ * mailto:contact AT sonarsource DOT com
+ *
+ * SonarQube is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * SonarQube is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+package org.sonar.server.computation;
+
+import java.util.List;
+import org.sonar.api.CoreProperties;
+import org.sonar.api.PropertyType;
+import org.sonar.api.config.PropertyDefinition;
+import org.sonar.server.computation.log.CeLogging;
+
+import static java.util.Arrays.asList;
+
+public class CePropertyDefinitions {
+  private CePropertyDefinitions() {
+    // only statics
+  }
+
+  public static List<PropertyDefinition> all() {
+    return asList(
+      PropertyDefinition.builder(CeLogging.MAX_LOGS_PROPERTY)
+        .name("Compute Engine Log Retention")
+        .description("Number of tasks to keep logs for a given project. Once the number of logs exceeds this limit, oldest logs are purged.")
+        .type(PropertyType.INTEGER)
+        .defaultValue("10")
+        .category(CoreProperties.CATEGORY_GENERAL)
+        .build());
+  }
+}
diff --git a/server/sonar-server/src/main/java/org/sonar/server/computation/CeWorkerImpl.java b/server/sonar-server/src/main/java/org/sonar/server/computation/CeWorkerImpl.java
index c46d0a1f470..3bcdea401cf 100644
--- a/server/sonar-server/src/main/java/org/sonar/server/computation/CeWorkerImpl.java
+++ b/server/sonar-server/src/main/java/org/sonar/server/computation/CeWorkerImpl.java
@@ -25,6 +25,7 @@ import org.sonar.api.utils.log.Logger;
 import org.sonar.api.utils.log.Loggers;
 import org.sonar.core.util.logs.Profiler;
 import org.sonar.db.ce.CeActivityDto;
+import org.sonar.server.computation.log.CeLogging;
 
 import static java.lang.String.format;
 
@@ -34,10 +35,12 @@ public class CeWorkerImpl implements CeWorker {
 
   private final CeQueue queue;
   private final ReportTaskProcessor reportTaskProcessor;
+  private final CeLogging ceLogging;
 
-  public CeWorkerImpl(CeQueue queue, ReportTaskProcessor reportTaskProcessor) {
+  public CeWorkerImpl(CeQueue queue, ReportTaskProcessor reportTaskProcessor, CeLogging ceLogging) {
     this.queue = queue;
     this.reportTaskProcessor = reportTaskProcessor;
+    this.ceLogging = ceLogging;
   }
 
   @Override
@@ -54,17 +57,18 @@ public class CeWorkerImpl implements CeWorker {
       return;
     }
 
-    // TODO delegate the message to the related task processor, according to task type
+    ceLogging.initForTask(task);
     Profiler profiler = Profiler.create(LOG).startInfo(format("Analysis of project %s (report %s)", task.getComponentKey(), task.getUuid()));
     try {
+      // TODO delegate the message to the related task processor, according to task type
       reportTaskProcessor.process(task);
       queue.remove(task, CeActivityDto.Status.SUCCESS);
     } catch (Throwable e) {
       LOG.error(format("Failed to process task %s", task.getUuid()), e);
       queue.remove(task, CeActivityDto.Status.FAILED);
     } finally {
-
       profiler.stopInfo();
+      ceLogging.clearForTask();
     }
   }
 }
diff --git a/server/sonar-server/src/main/java/org/sonar/server/computation/log/CeFileAppenderFactory.java b/server/sonar-server/src/main/java/org/sonar/server/computation/log/CeFileAppenderFactory.java
new file mode 100644
index 00000000000..d2eaacc7d10
--- /dev/null
+++ b/server/sonar-server/src/main/java/org/sonar/server/computation/log/CeFileAppenderFactory.java
@@ -0,0 +1,67 @@
+/*
+ * SonarQube, open source software quality management tool.
+ * Copyright (C) 2008-2014 SonarSource
+ * mailto:contact AT sonarsource DOT com
+ *
+ * SonarQube is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * SonarQube is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+package org.sonar.server.computation.log;
+
+import ch.qos.logback.classic.encoder.PatternLayoutEncoder;
+import ch.qos.logback.core.Context;
+import ch.qos.logback.core.FileAppender;
+import ch.qos.logback.core.sift.AppenderFactory;
+import com.google.common.annotations.VisibleForTesting;
+import java.io.File;
+import org.sonar.server.computation.CeTask;
+
+import static java.lang.String.format;
+
+/**
+ * Creates a Logback appender for a Compute Engine task. See
+ * http://logback.qos.ch/manual/loggingSeparation.html
+ */
+public class CeFileAppenderFactory<E> implements AppenderFactory<E> {
+
+  private static final String ENCODER_PATTERN = "%d{yyyy.MM.dd HH:mm:ss} %-5level [%logger{20}] %msg%n";
+
+  private final File ceLogsDir;
+
+  @VisibleForTesting
+  CeFileAppenderFactory(File ceLogsDir) {
+    this.ceLogsDir = ceLogsDir;
+  }
+
+  /**
+   * @param context
+   * @param discriminatingValue path of log file relative to the directory data/ce/logs
+   * @see CeLogging#initForTask(CeTask)
+   */
+  @Override
+  public FileAppender<E> buildAppender(Context context, String discriminatingValue) {
+    PatternLayoutEncoder consoleEncoder = new PatternLayoutEncoder();
+    consoleEncoder.setContext(context);
+    consoleEncoder.setPattern(ENCODER_PATTERN);
+    consoleEncoder.start();
+    FileAppender appender = new FileAppender<>();
+    appender.setContext(context);
+    appender.setEncoder(consoleEncoder);
+    appender.setName(format("ce-%s", discriminatingValue));
+    appender.setFile(new File(ceLogsDir, discriminatingValue).getAbsolutePath());
+    appender.start();
+    return appender;
+  }
+
+}
diff --git a/server/sonar-server/src/main/java/org/sonar/server/computation/log/CeLogAcceptFilter.java b/server/sonar-server/src/main/java/org/sonar/server/computation/log/CeLogAcceptFilter.java
new file mode 100644
index 00000000000..7458c1b2a0d
--- /dev/null
+++ b/server/sonar-server/src/main/java/org/sonar/server/computation/log/CeLogAcceptFilter.java
@@ -0,0 +1,36 @@
+/*
+ * SonarQube, open source software quality management tool.
+ * Copyright (C) 2008-2014 SonarSource
+ * mailto:contact AT sonarsource DOT com
+ *
+ * SonarQube is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * SonarQube is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+package org.sonar.server.computation.log;
+
+import ch.qos.logback.core.filter.Filter;
+import ch.qos.logback.core.spi.FilterReply;
+import org.slf4j.MDC;
+
+/**
+ * Keeps only the Compute Engine logs.
+ */
+public class CeLogAcceptFilter<E> extends Filter<E> {
+
+  @Override
+  public FilterReply decide(E o) {
+    return MDC.get(CeLogging.MDC_LOG_PATH) == null ? FilterReply.DENY : FilterReply.ACCEPT;
+  }
+
+}
diff --git a/server/sonar-server/src/main/java/org/sonar/server/computation/log/CeLogDenyFilter.java b/server/sonar-server/src/main/java/org/sonar/server/computation/log/CeLogDenyFilter.java
new file mode 100644
index 00000000000..bcaeb55ca8b
--- /dev/null
+++ b/server/sonar-server/src/main/java/org/sonar/server/computation/log/CeLogDenyFilter.java
@@ -0,0 +1,36 @@
+/*
+ * SonarQube, open source software quality management tool.
+ * Copyright (C) 2008-2014 SonarSource
+ * mailto:contact AT sonarsource DOT com
+ *
+ * SonarQube is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * SonarQube is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+package org.sonar.server.computation.log;
+
+import ch.qos.logback.core.filter.Filter;
+import ch.qos.logback.core.spi.FilterReply;
+import org.slf4j.MDC;
+
+/**
+ * Filters out the Compute Engine logs.
+ */
+public class CeLogDenyFilter<E> extends Filter<E> {
+
+  @Override
+  public FilterReply decide(E o) {
+    return MDC.get(CeLogging.MDC_LOG_PATH) == null ? FilterReply.ACCEPT : FilterReply.DENY;
+  }
+
+}
diff --git a/server/sonar-server/src/main/java/org/sonar/server/computation/log/CeLogging.java b/server/sonar-server/src/main/java/org/sonar/server/computation/log/CeLogging.java
new file mode 100644
index 00000000000..f1c0d8095db
--- /dev/null
+++ b/server/sonar-server/src/main/java/org/sonar/server/computation/log/CeLogging.java
@@ -0,0 +1,164 @@
+/*
+ * SonarQube, open source software quality management tool.
+ * Copyright (C) 2008-2014 SonarSource
+ * mailto:contact AT sonarsource DOT com
+ *
+ * SonarQube is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * SonarQube is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+package org.sonar.server.computation.log;
+
+import ch.qos.logback.classic.LoggerContext;
+import ch.qos.logback.classic.sift.MDCBasedDiscriminator;
+import ch.qos.logback.classic.sift.SiftingAppender;
+import ch.qos.logback.classic.spi.ILoggingEvent;
+import ch.qos.logback.core.Appender;
+import com.google.common.annotations.VisibleForTesting;
+import com.google.common.base.Optional;
+import java.io.File;
+import java.util.Collections;
+import java.util.List;
+import org.apache.commons.io.FileUtils;
+import org.apache.commons.io.comparator.LastModifiedFileComparator;
+import org.apache.commons.io.filefilter.FileFilterUtils;
+import org.apache.log4j.MDC;
+import org.sonar.api.config.Settings;
+import org.sonar.process.ProcessProperties;
+import org.sonar.process.Props;
+import org.sonar.server.computation.CeTask;
+
+import static com.google.common.base.Preconditions.checkArgument;
+import static com.google.common.collect.FluentIterable.from;
+import static com.google.common.collect.Lists.newArrayList;
+import static java.lang.String.format;
+
+/**
+ * Manages the logs written by Compute Engine:
+ * <ul>
+ *   <li>access to existing logs</li>
+ *   <li>configure logback when CE worker starts and stops processing a task</li>
+ * </ul>
+ */
+public class CeLogging {
+
+  @VisibleForTesting
+  static final String MDC_LOG_PATH = "ceLogPath";
+  public static final String MAX_LOGS_PROPERTY = "sonar.ce.maxLogsPerTask";
+
+  private final File logsDir;
+  private final int maxLogs;
+
+  public CeLogging(Settings settings) {
+    String dataDir = settings.getString(ProcessProperties.PATH_DATA);
+    checkArgument(dataDir != null, "Property %s is not set", ProcessProperties.PATH_DATA);
+    this.logsDir = logsDirFromDataDir(new File(dataDir));
+    this.maxLogs = settings.getInt(MAX_LOGS_PROPERTY);
+    if (maxLogs < 0) {
+      throw new IllegalArgumentException(format("Property %s must be positive. Got: %d", MAX_LOGS_PROPERTY, maxLogs));
+    }
+  }
+
+  @VisibleForTesting
+  CeLogging(File logsDir, int maxLogs) {
+    this.logsDir = logsDir;
+    this.maxLogs = maxLogs;
+  }
+
+  /**
+   * Gets the log file of a given task. It may not exist if it
+   * was purged or if the task does not exist.
+   */
+  public Optional<File> getFile(LogFileRef ref) {
+    File logFile = new File(logsDir, ref.getRelativePath());
+    if (logFile.exists()) {
+      return Optional.of(logFile);
+    }
+    return Optional.absent();
+  }
+
+  /**
+   * Initialize logging of a Compute Engine task. Must be called
+   * before first writing of log.
+   */
+  public void initForTask(CeTask task) {
+    LogFileRef ref = LogFileRef.from(task);
+    // Logback SiftingAppender requires to use a String, so
+    // the path is put but not the object LogFileRef
+    MDC.put(MDC_LOG_PATH, ref.getRelativePath());
+  }
+
+  /**
+   * Clean-up the logging of a task. Must be called after the last writing
+   * of log.
+   */
+  public void clearForTask() {
+    String relativePath = (String) MDC.get(MDC_LOG_PATH);
+    MDC.remove(MDC_LOG_PATH);
+
+    if (relativePath != null) {
+      purgeDir(new File(logsDir, relativePath).getParentFile());
+    }
+  }
+
+  @VisibleForTesting
+  void purgeDir(File dir) {
+    if (dir.exists()) {
+      List<File> logFiles = newArrayList(FileUtils.listFiles(dir, FileFilterUtils.fileFileFilter(), FileFilterUtils.falseFileFilter()));
+      if (logFiles.size() > maxLogs) {
+        Collections.sort(logFiles, LastModifiedFileComparator.LASTMODIFIED_COMPARATOR);
+        for (File logFile : from(logFiles).limit(logFiles.size() - maxLogs)) {
+          logFile.delete();
+        }
+      }
+    }
+  }
+
+  /**
+   * Directory which contains all the compute engine logs.
+   * Log files must be persistent among server restarts and upgrades, so they are
+   * stored into directory data/ but not into directories logs/ or temp/.
+   * @return the non-null directory. It may not exist at startup.
+   */
+  static File logsDirFromDataDir(File dataDir) {
+    return new File(dataDir, "ce/logs");
+  }
+
+  /**
+   * Create Logback configuration for enabling sift appender.
+   * A new log file is created for each task. It is based on MDC as long
+   * as Compute Engine is not executed in its
+   * own process but in the same process as web server.
+   */
+  public static Appender<ILoggingEvent> createAppenderConfiguration(LoggerContext ctx, Props processProps) {
+    File dataDir = new File(processProps.nonNullValue(ProcessProperties.PATH_DATA));
+    File logsDir = logsDirFromDataDir(dataDir);
+    return createAppenderConfiguration(ctx, logsDir);
+  }
+
+  static SiftingAppender createAppenderConfiguration(LoggerContext ctx, File logsDir) {
+    SiftingAppender siftingAppender = new SiftingAppender();
+    siftingAppender.addFilter(new CeLogAcceptFilter<ILoggingEvent>());
+    MDCBasedDiscriminator mdcDiscriminator = new MDCBasedDiscriminator();
+    mdcDiscriminator.setContext(ctx);
+    mdcDiscriminator.setKey(MDC_LOG_PATH);
+    mdcDiscriminator.setDefaultValue("error");
+    mdcDiscriminator.start();
+    siftingAppender.setContext(ctx);
+    siftingAppender.setDiscriminator(mdcDiscriminator);
+    siftingAppender.setAppenderFactory(new CeFileAppenderFactory(logsDir));
+    siftingAppender.setName("ce");
+    siftingAppender.start();
+    return siftingAppender;
+  }
+}
diff --git a/server/sonar-server/src/main/java/org/sonar/server/computation/log/LogFileRef.java b/server/sonar-server/src/main/java/org/sonar/server/computation/log/LogFileRef.java
new file mode 100644
index 00000000000..896b4b8a79b
--- /dev/null
+++ b/server/sonar-server/src/main/java/org/sonar/server/computation/log/LogFileRef.java
@@ -0,0 +1,105 @@
+/*
+ * SonarQube, open source software quality management tool.
+ * Copyright (C) 2008-2014 SonarSource
+ * mailto:contact AT sonarsource DOT com
+ *
+ * SonarQube is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * SonarQube is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+package org.sonar.server.computation.log;
+
+import com.google.common.annotations.VisibleForTesting;
+import java.util.regex.Pattern;
+import javax.annotation.CheckForNull;
+import javax.annotation.Nullable;
+import org.sonar.db.ce.CeActivityDto;
+import org.sonar.db.ce.CeQueueDto;
+import org.sonar.server.computation.CeTask;
+
+import static java.lang.String.format;
+
+public class LogFileRef {
+
+  // restricted white-list for now
+  private static final Pattern FILENAME_PATTERN = Pattern.compile("^[\\w\\-]*$");
+  private final String taskType;
+  private final String taskUuid;
+
+  @CheckForNull
+  private final String componentUuid;
+
+  public LogFileRef(String taskType, String taskUuid, @Nullable String componentUuid) {
+    this.taskType = requireValidFilename(taskType);
+    this.taskUuid = requireValidFilename(taskUuid);
+    this.componentUuid = requireValidFilename(componentUuid);
+  }
+
+  @VisibleForTesting
+  @CheckForNull
+  static String requireValidFilename(@Nullable String s) {
+    if (s != null && !FILENAME_PATTERN.matcher(s).matches()) {
+      throw new IllegalArgumentException(String.format("'%s' is not a valid filename for Compute Engine logs", s));
+    }
+    return s;
+  }
+
+  /**
+   * Path relative to the CE logs directory
+   */
+  public String getRelativePath() {
+    if (componentUuid == null) {
+      return format("%s/%s.log", taskType, taskUuid);
+    }
+    return format("%s/%s/%s.log", taskType, componentUuid, taskUuid);
+  }
+
+  @Override
+  public boolean equals(@Nullable Object o) {
+    if (this == o) {
+      return true;
+    }
+    if (o == null || getClass() != o.getClass()) {
+      return false;
+    }
+    LogFileRef that = (LogFileRef) o;
+    if (!taskType.equals(that.taskType)) {
+      return false;
+    }
+    if (!taskUuid.equals(that.taskUuid)) {
+      return false;
+    }
+    return !(componentUuid != null ? !componentUuid.equals(that.componentUuid) : that.componentUuid != null);
+
+  }
+
+  @Override
+  public int hashCode() {
+    int result = taskType.hashCode();
+    result = 31 * result + taskUuid.hashCode();
+    result = 31 * result + (componentUuid != null ? componentUuid.hashCode() : 0);
+    return result;
+  }
+
+  public static LogFileRef from(CeActivityDto dto) {
+    return new LogFileRef(dto.getTaskType(), dto.getUuid(), dto.getComponentUuid());
+  }
+
+  public static LogFileRef from(CeQueueDto dto) {
+    return new LogFileRef(dto.getTaskType(), dto.getUuid(), dto.getComponentUuid());
+  }
+
+  public static LogFileRef from(CeTask task) {
+    return new LogFileRef(task.getType(), task.getUuid(), task.getComponentUuid());
+  }
+}
diff --git a/server/sonar-server/src/main/java/org/sonar/server/computation/log/package-info.java b/server/sonar-server/src/main/java/org/sonar/server/computation/log/package-info.java
new file mode 100644
index 00000000000..445e6a5ad35
--- /dev/null
+++ b/server/sonar-server/src/main/java/org/sonar/server/computation/log/package-info.java
@@ -0,0 +1,23 @@
+/*
+ * SonarQube, open source software quality management tool.
+ * Copyright (C) 2008-2014 SonarSource
+ * mailto:contact AT sonarsource DOT com
+ *
+ * SonarQube is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * SonarQube is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+@ParametersAreNonnullByDefault
+package org.sonar.server.computation.log;
+
+import javax.annotation.ParametersAreNonnullByDefault;
diff --git a/server/sonar-server/src/main/java/org/sonar/server/computation/ws/CeWsModule.java b/server/sonar-server/src/main/java/org/sonar/server/computation/ws/CeWsModule.java
index 202c5e010fb..79bd61ce1c3 100644
--- a/server/sonar-server/src/main/java/org/sonar/server/computation/ws/CeWsModule.java
+++ b/server/sonar-server/src/main/java/org/sonar/server/computation/ws/CeWsModule.java
@@ -30,6 +30,7 @@ public class CeWsModule extends Module {
       CeQueueWsAction.class,
       CeWs.class,
       IsQueueEmptyWs.class,
+      LogsWsAction.class,
       ProjectWsAction.class,
       SubmitWsAction.class,
       TaskFormatter.class,
diff --git a/server/sonar-server/src/main/java/org/sonar/server/computation/ws/LogsWsAction.java b/server/sonar-server/src/main/java/org/sonar/server/computation/ws/LogsWsAction.java
new file mode 100644
index 00000000000..1d654e9402e
--- /dev/null
+++ b/server/sonar-server/src/main/java/org/sonar/server/computation/ws/LogsWsAction.java
@@ -0,0 +1,114 @@
+/*
+ * SonarQube, open source software quality management tool.
+ * Copyright (C) 2008-2014 SonarSource
+ * mailto:contact AT sonarsource DOT com
+ *
+ * SonarQube is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * SonarQube is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+package org.sonar.server.computation.ws;
+
+import com.google.common.base.Optional;
+import java.io.File;
+import java.io.IOException;
+import org.apache.commons.io.FileUtils;
+import org.sonar.api.server.ws.Request;
+import org.sonar.api.server.ws.Response;
+import org.sonar.api.server.ws.WebService;
+import org.sonar.api.web.UserRole;
+import org.sonar.core.util.Uuids;
+import org.sonar.db.DbClient;
+import org.sonar.db.DbSession;
+import org.sonar.db.ce.CeActivityDto;
+import org.sonar.db.ce.CeQueueDto;
+import org.sonar.server.computation.log.CeLogging;
+import org.sonar.server.computation.log.LogFileRef;
+import org.sonar.server.exceptions.NotFoundException;
+import org.sonar.server.plugins.MimeTypes;
+import org.sonar.server.user.UserSession;
+
+import static java.lang.String.format;
+
+public class LogsWsAction implements CeWsAction {
+
+  public static final String ACTION = "logs";
+  public static final String PARAM_TASK_UUID = "taskId";
+
+  private final DbClient dbClient;
+  private final UserSession userSession;
+  private final CeLogging ceLogging;
+
+  public LogsWsAction(DbClient dbClient, UserSession userSession, CeLogging ceLogging) {
+    this.dbClient = dbClient;
+    this.userSession = userSession;
+    this.ceLogging = ceLogging;
+  }
+
+  @Override
+  public void define(WebService.NewController controller) {
+    WebService.NewAction action = controller.createAction(ACTION)
+      .setDescription("Logs of a task. Returns HTTP code 404 if task does not " +
+        "exist or if logs are not available. Requires system administration permission.")
+      .setInternal(true)
+      .setHandler(this);
+
+    action
+      .createParam(PARAM_TASK_UUID)
+      .setRequired(true)
+      .setDescription("Id of task")
+      .setExampleValue(Uuids.UUID_EXAMPLE_01);
+  }
+
+  @Override
+  public void handle(Request wsRequest, Response wsResponse) throws Exception {
+    userSession.checkGlobalPermission(UserRole.ADMIN);
+
+    String taskUuid = wsRequest.mandatoryParam(PARAM_TASK_UUID);
+    LogFileRef ref = loadLogRef(taskUuid);
+    Optional<File> logFile = ceLogging.getFile(ref);
+    if (logFile.isPresent()) {
+      writeFile(logFile.get(), wsResponse);
+    } else {
+      throw new NotFoundException(format("Logs of task %s not found", taskUuid));
+    }
+  }
+
+  private LogFileRef loadLogRef(String taskUuid) {
+    DbSession dbSession = dbClient.openSession(false);
+    try {
+      Optional<CeQueueDto> queueDto = dbClient.ceQueueDao().selectByUuid(dbSession, taskUuid);
+      if (queueDto.isPresent()) {
+        return LogFileRef.from(queueDto.get());
+      }
+      Optional<CeActivityDto> activityDto = dbClient.ceActivityDao().selectByUuid(dbSession, taskUuid);
+      if (activityDto.isPresent()) {
+        return LogFileRef.from(activityDto.get());
+      }
+      throw new NotFoundException(format("Task %s not found", taskUuid));
+
+    } finally {
+      dbClient.closeSession(dbSession);
+    }
+  }
+
+  private static void writeFile(File file, Response wsResponse) {
+    try {
+      Response.Stream stream = wsResponse.stream();
+      stream.setMediaType(MimeTypes.TXT);
+      FileUtils.copyFile(file, stream.output());
+    } catch (IOException e) {
+      throw new IllegalStateException("Fail to copy compute engine log file to HTTP response: " + file.getAbsolutePath(), e);
+    }
+  }
+}
diff --git a/server/sonar-server/src/main/java/org/sonar/server/computation/ws/TaskFormatter.java b/server/sonar-server/src/main/java/org/sonar/server/computation/ws/TaskFormatter.java
index 75519eaf6ce..cfaaf639da5 100644
--- a/server/sonar-server/src/main/java/org/sonar/server/computation/ws/TaskFormatter.java
+++ b/server/sonar-server/src/main/java/org/sonar/server/computation/ws/TaskFormatter.java
@@ -33,14 +33,22 @@ import org.sonar.db.DbSession;
 import org.sonar.db.ce.CeActivityDto;
 import org.sonar.db.ce.CeQueueDto;
 import org.sonar.db.component.ComponentDto;
+import org.sonar.server.computation.log.CeLogging;
+import org.sonar.server.computation.log.LogFileRef;
 import org.sonarqube.ws.WsCe;
 
+/**
+ * Converts {@link CeActivityDto} and {@link CeQueueDto} to the protobuf objects
+ * used to write WS responses (see ws-ce.proto in module sonar-ws)
+ */
 public class TaskFormatter {
 
   private final DbClient dbClient;
+  private final CeLogging ceLogging;
 
-  public TaskFormatter(DbClient dbClient) {
+  public TaskFormatter(DbClient dbClient, CeLogging ceLogging) {
     this.dbClient = dbClient;
+    this.ceLogging = ceLogging;
   }
 
   public List<WsCe.Task> formatQueue(DbSession dbSession, List<CeQueueDto> dtos) {
@@ -61,6 +69,7 @@ public class TaskFormatter {
     builder.setId(dto.getUuid());
     builder.setStatus(WsCe.TaskStatus.valueOf(dto.getStatus().name()));
     builder.setType(dto.getTaskType());
+    builder.setLogs(ceLogging.getFile(LogFileRef.from(dto)).isPresent());
     if (dto.getComponentUuid() != null) {
       builder.setComponentId(dto.getComponentUuid());
       buildComponent(builder, componentCache.get(dto.getComponentUuid()));
@@ -93,6 +102,7 @@ public class TaskFormatter {
     builder.setId(dto.getUuid());
     builder.setStatus(WsCe.TaskStatus.valueOf(dto.getStatus().name()));
     builder.setType(dto.getTaskType());
+    builder.setLogs(ceLogging.getFile(LogFileRef.from(dto)).isPresent());
     if (dto.getComponentUuid() != null) {
       builder.setComponentId(dto.getComponentUuid());
       buildComponent(builder, componentCache.get(dto.getComponentUuid()));
diff --git a/server/sonar-server/src/main/java/org/sonar/server/computation/ws/TaskWsAction.java b/server/sonar-server/src/main/java/org/sonar/server/computation/ws/TaskWsAction.java
index a1305a48dc7..b79bc416424 100644
--- a/server/sonar-server/src/main/java/org/sonar/server/computation/ws/TaskWsAction.java
+++ b/server/sonar-server/src/main/java/org/sonar/server/computation/ws/TaskWsAction.java
@@ -87,6 +87,5 @@ public class TaskWsAction implements CeWsAction {
     } finally {
       dbClient.closeSession(dbSession);
     }
-
   }
 }
diff --git a/server/sonar-server/src/main/java/org/sonar/server/platform/platformlevel/PlatformLevel1.java b/server/sonar-server/src/main/java/org/sonar/server/platform/platformlevel/PlatformLevel1.java
index 97cffa83c23..1c755e96f51 100644
--- a/server/sonar-server/src/main/java/org/sonar/server/platform/platformlevel/PlatformLevel1.java
+++ b/server/sonar-server/src/main/java/org/sonar/server/platform/platformlevel/PlatformLevel1.java
@@ -33,6 +33,7 @@ import org.sonar.db.purge.PurgeProfiler;
 import org.sonar.db.semaphore.SemaphoresImpl;
 import org.sonar.db.version.DatabaseVersion;
 import org.sonar.db.version.MigrationStepModule;
+import org.sonar.server.computation.CePropertyDefinitions;
 import org.sonar.server.db.DbClient;
 import org.sonar.server.db.EmbeddedDatabaseFactory;
 import org.sonar.server.issue.index.IssueIndex;
@@ -118,6 +119,7 @@ public class PlatformLevel1 extends PlatformLevel {
       org.sonar.core.properties.PropertiesDao.class,
       org.sonar.core.persistence.MyBatis.class);
     addAll(CorePropertyDefinitions.all());
+    addAll(CePropertyDefinitions.all());
     add(MigrationStepModule.class);
   }
 
diff --git a/server/sonar-server/src/main/java/org/sonar/server/platform/platformlevel/PlatformLevel4.java b/server/sonar-server/src/main/java/org/sonar/server/platform/platformlevel/PlatformLevel4.java
index 8529c5cdf41..3e7c66f713f 100644
--- a/server/sonar-server/src/main/java/org/sonar/server/platform/platformlevel/PlatformLevel4.java
+++ b/server/sonar-server/src/main/java/org/sonar/server/platform/platformlevel/PlatformLevel4.java
@@ -31,8 +31,6 @@ import org.sonar.api.rules.AnnotationRuleParser;
 import org.sonar.api.rules.XMLRuleParser;
 import org.sonar.api.server.rule.RulesDefinitionXmlLoader;
 import org.sonar.core.component.DefaultResourceTypes;
-import org.sonar.server.computation.dbcleaner.IndexPurgeListener;
-import org.sonar.server.computation.dbcleaner.ProjectCleaner;
 import org.sonar.core.issue.IssueUpdater;
 import org.sonar.core.issue.workflow.FunctionExecutor;
 import org.sonar.core.issue.workflow.IssueWorkflow;
@@ -71,6 +69,9 @@ import org.sonar.server.computation.CleanReportQueueListener;
 import org.sonar.server.computation.ComputeEngineProcessingModule;
 import org.sonar.server.computation.ReportFiles;
 import org.sonar.server.computation.ReportSubmitter;
+import org.sonar.server.computation.dbcleaner.IndexPurgeListener;
+import org.sonar.server.computation.dbcleaner.ProjectCleaner;
+import org.sonar.server.computation.log.CeLogging;
 import org.sonar.server.computation.monitoring.CEQueueStatusImpl;
 import org.sonar.server.computation.monitoring.ComputeEngineQueueMonitor;
 import org.sonar.server.computation.ws.CeWsModule;
@@ -718,6 +719,7 @@ public class PlatformLevel4 extends PlatformLevel {
       ReportFiles.class,
       ComputeEngineProcessingModule.class,
       CeWsModule.class,
+      CeLogging.class,
       DefaultPeriodCleaner.class,
       ProjectCleaner.class,
       ProjectSettingsFactory.class,
diff --git a/server/sonar-server/src/main/resources/org/sonar/server/computation/ws/activity-example.json b/server/sonar-server/src/main/resources/org/sonar/server/computation/ws/activity-example.json
index b7b3b270079..f6b40d89ec2 100644
--- a/server/sonar-server/src/main/resources/org/sonar/server/computation/ws/activity-example.json
+++ b/server/sonar-server/src/main/resources/org/sonar/server/computation/ws/activity-example.json
@@ -16,7 +16,8 @@
       "submitterLogin": "john",
       "startedAt": "2015-08-13T23:35:00+0200",
       "finishedAt": "2015-08-13T23:35:10+0200",
-      "executionTimeMs": 10000
+      "executionTimeMs": 10000,
+      "logs": true
     },
     {
       "id": "AU_dO1vsORa8_beWCwmP",
@@ -28,7 +29,8 @@
       "submittedAt": "2015-09-17T23:34:59+0200",
       "startedAt": "2015-09-17T23:35:00+0200",
       "finishedAt": "2015-08-13T23:37:00+0200",
-      "executionTimeMs": 120000
+      "executionTimeMs": 120000,
+      "logs": false
     }
   ]
 }
diff --git a/server/sonar-server/src/main/resources/org/sonar/server/computation/ws/project-example.json b/server/sonar-server/src/main/resources/org/sonar/server/computation/ws/project-example.json
index 3bdd4945c10..747ca57fe00 100644
--- a/server/sonar-server/src/main/resources/org/sonar/server/computation/ws/project-example.json
+++ b/server/sonar-server/src/main/resources/org/sonar/server/computation/ws/project-example.json
@@ -7,7 +7,8 @@
       "componentKey": "com.github.kevinsawicki:http-request-parent",
       "componentName": "HttpRequest",
       "status": "PENDING",
-      "submittedAt": "2015-09-21T19:28:54+0200"
+      "submittedAt": "2015-09-21T19:28:54+0200",
+      "logs": true
     }
   ],
   "current": {
@@ -20,6 +21,7 @@
     "submittedAt": "2015-09-21T19:25:49+0200",
     "startedAt": "2015-09-21T19:25:57+0200",
     "finishedAt": "2015-09-21T19:25:58+0200",
-    "executionTimeMs": 1371
+    "executionTimeMs": 1371,
+    "logs": true
   }
 }
diff --git a/server/sonar-server/src/main/resources/org/sonar/server/computation/ws/queue-example.json b/server/sonar-server/src/main/resources/org/sonar/server/computation/ws/queue-example.json
index 12ff5cc5cc8..82f277d2830 100644
--- a/server/sonar-server/src/main/resources/org/sonar/server/computation/ws/queue-example.json
+++ b/server/sonar-server/src/main/resources/org/sonar/server/computation/ws/queue-example.json
@@ -8,7 +8,8 @@
       "componentName": "Project One",
       "status": "IN_PROGRESS",
       "submittedAt": "2015-08-13T23:34:59+0200",
-      "submitterLogin": "john"
+      "submitterLogin": "john",
+      "logs": true
     },
     {
       "id": "AU_dO1vsORa8_beWCwmP",
@@ -18,7 +19,8 @@
       "componentName": "Project Two",
       "status": "PENDING",
       "submittedAt": "2015-09-17T23:34:59+0200",
-      "startedAt": "2015-09-17T23:35:00+0200"
+      "startedAt": "2015-09-17T23:35:00+0200",
+      "logs": true
     }
   ]
 }
diff --git a/server/sonar-server/src/test/java/org/sonar/server/app/ProgrammaticLogbackValveTest.java b/server/sonar-server/src/test/java/org/sonar/server/app/ProgrammaticLogbackValveTest.java
index c1d2b18f4be..95672638f29 100644
--- a/server/sonar-server/src/test/java/org/sonar/server/app/ProgrammaticLogbackValveTest.java
+++ b/server/sonar-server/src/test/java/org/sonar/server/app/ProgrammaticLogbackValveTest.java
@@ -21,7 +21,6 @@ package org.sonar.server.app;
 
 import ch.qos.logback.access.spi.IAccessEvent;
 import ch.qos.logback.core.ConsoleAppender;
-
 import org.apache.catalina.Container;
 import org.junit.AfterClass;
 import org.junit.Test;
@@ -42,7 +41,7 @@ public class ProgrammaticLogbackValveTest {
     ProgrammaticLogbackValve valve = new ProgrammaticLogbackValve();
     valve.setContainer(mock(Container.class));
     LogbackHelper helper = new LogbackHelper();
-    ConsoleAppender<IAccessEvent> appender = helper.newConsoleAppender(valve, "CONSOLE", "combined");
+    ConsoleAppender<IAccessEvent> appender = helper.newConsoleAppender(valve, "CONSOLE", "combined", null);
     valve.addAppender(appender);
 
     valve.start();
diff --git a/server/sonar-server/src/test/java/org/sonar/server/app/WebLoggingTest.java b/server/sonar-server/src/test/java/org/sonar/server/app/WebLoggingTest.java
index 648e9c58aa4..80bfad290b0 100644
--- a/server/sonar-server/src/test/java/org/sonar/server/app/WebLoggingTest.java
+++ b/server/sonar-server/src/test/java/org/sonar/server/app/WebLoggingTest.java
@@ -24,22 +24,39 @@ import ch.qos.logback.classic.Logger;
 import ch.qos.logback.classic.LoggerContext;
 import ch.qos.logback.core.Appender;
 import ch.qos.logback.core.ConsoleAppender;
+import ch.qos.logback.core.joran.spi.JoranException;
+import java.io.IOException;
+import java.util.Properties;
 import org.junit.AfterClass;
+import org.junit.Before;
+import org.junit.Rule;
 import org.junit.Test;
+import org.junit.rules.TemporaryFolder;
 import org.sonar.process.LogbackHelper;
+import org.sonar.process.ProcessProperties;
 import org.sonar.process.Props;
 
-import java.util.Properties;
-
 import static org.assertj.core.api.Assertions.assertThat;
 
 public class WebLoggingTest {
 
+  @Rule
+  public TemporaryFolder temp = new TemporaryFolder();
+
   Props props = new Props(new Properties());
   WebLogging underTest = new WebLogging();
 
+  /**
+   * Path to data dir must be set for Compute Engine logging.
+   * @see org.sonar.server.computation.log.CeFileAppenderFactory
+   */
+  @Before
+  public void setUp() throws IOException {
+    props.set(ProcessProperties.PATH_DATA, temp.newFolder().getAbsolutePath());
+  }
+
   @AfterClass
-  public static void resetLogback() throws Exception {
+  public static void resetLogback() throws JoranException {
     new LogbackHelper().resetFromXml("/logback-test.xml");
   }
 
diff --git a/server/sonar-server/src/test/java/org/sonar/server/computation/CePropertyDefinitionsTest.java b/server/sonar-server/src/test/java/org/sonar/server/computation/CePropertyDefinitionsTest.java
new file mode 100644
index 00000000000..592ce673174
--- /dev/null
+++ b/server/sonar-server/src/test/java/org/sonar/server/computation/CePropertyDefinitionsTest.java
@@ -0,0 +1,38 @@
+/*
+ * SonarQube, open source software quality management tool.
+ * Copyright (C) 2008-2014 SonarSource
+ * mailto:contact AT sonarsource DOT com
+ *
+ * SonarQube is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * SonarQube is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+package org.sonar.server.computation;
+
+import org.junit.Test;
+import org.sonar.test.TestUtils;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class CePropertyDefinitionsTest {
+
+  @Test
+  public void all() {
+    assertThat(CePropertyDefinitions.all()).isNotEmpty();
+  }
+
+  @Test
+  public void only_statics() {
+    assertThat(TestUtils.hasOnlyPrivateConstructors(CePropertyDefinitions.class));
+  }
+}
diff --git a/server/sonar-server/src/test/java/org/sonar/server/computation/CeWorkerImplTest.java b/server/sonar-server/src/test/java/org/sonar/server/computation/CeWorkerImplTest.java
index 5b484e02837..e2175c98bcd 100644
--- a/server/sonar-server/src/test/java/org/sonar/server/computation/CeWorkerImplTest.java
+++ b/server/sonar-server/src/test/java/org/sonar/server/computation/CeWorkerImplTest.java
@@ -21,12 +21,14 @@ package org.sonar.server.computation;
 
 import com.google.common.base.Optional;
 import org.junit.Test;
+import org.mockito.InOrder;
+import org.mockito.Mockito;
 import org.sonar.db.ce.CeActivityDto;
 import org.sonar.db.ce.CeTaskTypes;
+import org.sonar.server.computation.log.CeLogging;
 
 import static org.mockito.Mockito.doThrow;
 import static org.mockito.Mockito.mock;
-import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.verifyZeroInteractions;
 import static org.mockito.Mockito.when;
 
@@ -34,7 +36,8 @@ public class CeWorkerImplTest {
 
   CeQueue queue = mock(CeQueueImpl.class);
   ReportTaskProcessor taskProcessor = mock(ReportTaskProcessor.class);
-  CeWorker underTest = new CeWorkerImpl(queue, taskProcessor);
+  CeLogging ceLogging = mock(CeLogging.class);
+  CeWorker underTest = new CeWorkerImpl(queue, taskProcessor, ceLogging);
 
   @Test
   public void no_pending_tasks_in_queue() throws Exception {
@@ -42,7 +45,7 @@ public class CeWorkerImplTest {
 
     underTest.run();
 
-    verifyZeroInteractions(taskProcessor);
+    verifyZeroInteractions(taskProcessor, ceLogging);
   }
 
   @Test
@@ -52,8 +55,11 @@ public class CeWorkerImplTest {
 
     underTest.run();
 
-    verify(taskProcessor).process(task);
-    verify(queue).remove(task, CeActivityDto.Status.SUCCESS);
+    InOrder inOrder = Mockito.inOrder(ceLogging, taskProcessor, queue);
+    inOrder.verify(ceLogging).initForTask(task);
+    inOrder.verify(taskProcessor).process(task);
+    inOrder.verify(queue).remove(task, CeActivityDto.Status.SUCCESS);
+    inOrder.verify(ceLogging).clearForTask();
   }
 
   @Test
@@ -64,7 +70,10 @@ public class CeWorkerImplTest {
 
     underTest.run();
 
-    verify(taskProcessor).process(task);
-    verify(queue).remove(task, CeActivityDto.Status.FAILED);
+    InOrder inOrder = Mockito.inOrder(ceLogging, taskProcessor, queue);
+    inOrder.verify(ceLogging).initForTask(task);
+    inOrder.verify(taskProcessor).process(task);
+    inOrder.verify(queue).remove(task, CeActivityDto.Status.FAILED);
+    inOrder.verify(ceLogging).clearForTask();
   }
 }
diff --git a/server/sonar-server/src/test/java/org/sonar/server/computation/log/CeFileAppenderFactoryTest.java b/server/sonar-server/src/test/java/org/sonar/server/computation/log/CeFileAppenderFactoryTest.java
new file mode 100644
index 00000000000..525942e2169
--- /dev/null
+++ b/server/sonar-server/src/test/java/org/sonar/server/computation/log/CeFileAppenderFactoryTest.java
@@ -0,0 +1,46 @@
+/*
+ * SonarQube, open source software quality management tool.
+ * Copyright (C) 2008-2014 SonarSource
+ * mailto:contact AT sonarsource DOT com
+ *
+ * SonarQube is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * SonarQube is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+package org.sonar.server.computation.log;
+
+import ch.qos.logback.classic.LoggerContext;
+import ch.qos.logback.core.FileAppender;
+import java.io.File;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.TemporaryFolder;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class CeFileAppenderFactoryTest {
+
+  @Rule
+  public TemporaryFolder temp = new TemporaryFolder();
+
+  @Test
+  public void buildAppender() throws Exception {
+    File logsDir = temp.newFolder();
+    CeFileAppenderFactory factory = new CeFileAppenderFactory(logsDir);
+
+    FileAppender underTest = factory.buildAppender(new LoggerContext(), "uuid_1.log");
+
+    assertThat(new File(underTest.getFile())).isEqualTo(new File(logsDir, "uuid_1.log"));
+
+  }
+}
diff --git a/server/sonar-server/src/test/java/org/sonar/server/computation/log/CeLogAcceptFilterTest.java b/server/sonar-server/src/test/java/org/sonar/server/computation/log/CeLogAcceptFilterTest.java
new file mode 100644
index 00000000000..11ede09e9ca
--- /dev/null
+++ b/server/sonar-server/src/test/java/org/sonar/server/computation/log/CeLogAcceptFilterTest.java
@@ -0,0 +1,52 @@
+/*
+ * SonarQube, open source software quality management tool.
+ * Copyright (C) 2008-2014 SonarSource
+ * mailto:contact AT sonarsource DOT com
+ *
+ * SonarQube is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * SonarQube is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+package org.sonar.server.computation.log;
+
+import ch.qos.logback.core.filter.Filter;
+import ch.qos.logback.core.spi.FilterReply;
+import org.apache.log4j.MDC;
+import org.junit.After;
+import org.junit.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class CeLogAcceptFilterTest {
+
+  private static final Object UNUSED = "";
+
+  Filter underTest = new CeLogAcceptFilter();
+
+  @After
+  public void tearDown() {
+    MDC.clear();
+  }
+
+  @Test
+  public void reject_non_ce_logs() {
+    assertThat(underTest.decide(UNUSED)).isEqualTo(FilterReply.DENY);
+  }
+
+  @Test
+  public void accept_ce_logs() {
+    MDC.put(CeLogging.MDC_LOG_PATH, "abc.log");
+    assertThat(underTest.decide(UNUSED)).isEqualTo(FilterReply.ACCEPT);
+  }
+
+}
diff --git a/server/sonar-server/src/test/java/org/sonar/server/computation/log/CeLogDenyFilterTest.java b/server/sonar-server/src/test/java/org/sonar/server/computation/log/CeLogDenyFilterTest.java
new file mode 100644
index 00000000000..ce15009781c
--- /dev/null
+++ b/server/sonar-server/src/test/java/org/sonar/server/computation/log/CeLogDenyFilterTest.java
@@ -0,0 +1,52 @@
+/*
+ * SonarQube, open source software quality management tool.
+ * Copyright (C) 2008-2014 SonarSource
+ * mailto:contact AT sonarsource DOT com
+ *
+ * SonarQube is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * SonarQube is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+package org.sonar.server.computation.log;
+
+import ch.qos.logback.core.filter.Filter;
+import ch.qos.logback.core.spi.FilterReply;
+import org.apache.log4j.MDC;
+import org.junit.After;
+import org.junit.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class CeLogDenyFilterTest {
+
+  private static final Object UNUSED = "";
+
+  Filter underTest = new CeLogDenyFilter();
+
+  @After
+  public void tearDown() {
+    MDC.clear();
+  }
+
+  @Test
+  public void accept_non_ce_logs() {
+    assertThat(underTest.decide(UNUSED)).isEqualTo(FilterReply.ACCEPT);
+  }
+
+  @Test
+  public void deny_ce_logs() {
+    MDC.put(CeLogging.MDC_LOG_PATH, "abc.log");
+    assertThat(underTest.decide(UNUSED)).isEqualTo(FilterReply.DENY);
+  }
+
+}
diff --git a/server/sonar-server/src/test/java/org/sonar/server/computation/log/CeLoggingTest.java b/server/sonar-server/src/test/java/org/sonar/server/computation/log/CeLoggingTest.java
new file mode 100644
index 00000000000..9e6aeca37d1
--- /dev/null
+++ b/server/sonar-server/src/test/java/org/sonar/server/computation/log/CeLoggingTest.java
@@ -0,0 +1,154 @@
+/*
+ * SonarQube, open source software quality management tool.
+ * Copyright (C) 2008-2014 SonarSource
+ * mailto:contact AT sonarsource DOT com
+ *
+ * SonarQube is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * SonarQube is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+package org.sonar.server.computation.log;
+
+import ch.qos.logback.classic.LoggerContext;
+import ch.qos.logback.classic.sift.SiftingAppender;
+import ch.qos.logback.classic.spi.ILoggingEvent;
+import ch.qos.logback.core.filter.Filter;
+import com.google.common.base.Optional;
+import java.io.File;
+import java.io.IOException;
+import java.util.List;
+import org.apache.commons.io.FileUtils;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.ExpectedException;
+import org.junit.rules.TemporaryFolder;
+import org.slf4j.MDC;
+import org.sonar.api.config.Settings;
+import org.sonar.process.ProcessProperties;
+import org.sonar.server.computation.CeTask;
+
+import static java.lang.String.format;
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class CeLoggingTest {
+
+  @Rule
+  public ExpectedException expectedException = ExpectedException.none();
+
+  @Rule
+  public TemporaryFolder temp = new TemporaryFolder();
+
+  @Test
+  public void getFile() throws IOException {
+    File dataDir = temp.newFolder();
+    Settings settings = new Settings();
+    settings.setProperty(ProcessProperties.PATH_DATA, dataDir.getAbsolutePath());
+
+    CeLogging underTest = new CeLogging(settings);
+    LogFileRef ref = new LogFileRef("TYPE1", "TASK1", "COMPONENT1");
+
+    // file does not exist
+    Optional<File> file = underTest.getFile(ref);
+    assertThat(file.isPresent()).isFalse();
+
+    File logFile = new File(dataDir, "ce/logs/" + ref.getRelativePath());
+    FileUtils.touch(logFile);
+    file = underTest.getFile(ref);
+    assertThat(file.isPresent()).isTrue();
+    assertThat(file.get()).isEqualTo(logFile);
+  }
+
+  @Test(expected = IllegalArgumentException.class)
+  public void fail_if_data_dir_is_not_set() {
+    new CeLogging(new Settings());
+  }
+
+  @Test
+  public void use_MDC_to_store_path_to_in_progress_task_logs() throws IOException {
+    CeLogging underTest = new CeLogging(temp.newFolder(), 5);
+
+    CeTask task = new CeTask.Builder().setType("TYPE1").setUuid("U1").build();
+    underTest.initForTask(task);
+    assertThat(MDC.get(CeLogging.MDC_LOG_PATH)).isNotEmpty().isEqualTo(LogFileRef.from(task).getRelativePath());
+    underTest.clearForTask();
+    assertThat(MDC.get(CeLogging.MDC_LOG_PATH)).isNull();
+  }
+
+  @Test
+  public void delete_oldest_files_of_same_directory_to_keep_only_max_allowed_files() throws IOException {
+    File dir = temp.newFolder();
+    for (int i = 1; i <= 5; i++) {
+      File file = new File(dir, format("U%d.log", i));
+      FileUtils.touch(file);
+      // see javadoc: "all platforms support file-modification times to the nearest second,
+      // but some provide more precision" --> increment by second, not by millisecond
+      file.setLastModified(1_450_000_000_000L + i * 1000);
+    }
+    assertThat(dir.listFiles()).hasSize(5);
+
+    // keep 3 files in each dir
+    CeLogging underTest = new CeLogging(dir, 3);
+    underTest.purgeDir(dir);
+
+    assertThat(dir.listFiles()).hasSize(3);
+    assertThat(dir.listFiles()).extracting("name")
+      .containsOnly("U3.log", "U4.log", "U5.log");
+  }
+
+  @Test
+  public void do_not_delete_files_if_dir_has_less_files_than_max_allowed() throws IOException {
+    File dir = temp.newFolder();
+    FileUtils.touch(new File(dir, "U1.log"));
+
+    CeLogging underTest = new CeLogging(dir, 5);
+    underTest.purgeDir(dir);
+
+    assertThat(dir.listFiles()).extracting("name").containsOnly("U1.log");
+  }
+
+  @Test
+  public void do_not_keep_any_logs() throws IOException {
+    File dir = temp.newFolder();
+    FileUtils.touch(new File(dir, "U1.log"));
+
+    CeLogging underTest = new CeLogging(dir, 0);
+    underTest.purgeDir(dir);
+
+    assertThat(dir.listFiles()).isEmpty();
+  }
+
+  @Test
+  public void fail_if_max_logs_settings_is_negative() throws IOException {
+    expectedException.expect(IllegalArgumentException.class);
+    expectedException.expectMessage("Property sonar.ce.maxLogsPerTask must be positive. Got: -1");
+
+    Settings settings = new Settings();
+    settings.setProperty(ProcessProperties.PATH_DATA, temp.newFolder().getAbsolutePath());
+    settings.setProperty(CeLogging.MAX_LOGS_PROPERTY, -1);
+    new CeLogging(settings);
+  }
+
+  @Test
+  public void createConfiguration() throws Exception {
+    File logsDir = temp.newFolder();
+    SiftingAppender siftingAppender = CeLogging.createAppenderConfiguration(new LoggerContext(), logsDir);
+
+    // filter on CE logs
+    List<Filter<ILoggingEvent>> filters = siftingAppender.getCopyOfAttachedFiltersList();
+    assertThat(filters).hasSize(1);
+    assertThat(filters.get(0)).isInstanceOf(CeLogAcceptFilter.class);
+
+    assertThat(siftingAppender.getDiscriminator().getKey()).isEqualTo(CeLogging.MDC_LOG_PATH);
+  }
+
+}
diff --git a/server/sonar-server/src/test/java/org/sonar/server/computation/log/LogFileRefTest.java b/server/sonar-server/src/test/java/org/sonar/server/computation/log/LogFileRefTest.java
new file mode 100644
index 00000000000..c7a1d47c18f
--- /dev/null
+++ b/server/sonar-server/src/test/java/org/sonar/server/computation/log/LogFileRefTest.java
@@ -0,0 +1,84 @@
+/*
+ * SonarQube, open source software quality management tool.
+ * Copyright (C) 2008-2014 SonarSource
+ * mailto:contact AT sonarsource DOT com
+ *
+ * SonarQube is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * SonarQube is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+package org.sonar.server.computation.log;
+
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.ExpectedException;
+import org.sonar.db.ce.CeTaskTypes;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class LogFileRefTest {
+
+  @Rule
+  public ExpectedException expectedException = ExpectedException.none();
+
+  @Test
+  public void equals_hashCode() {
+    LogFileRef ref1 = new LogFileRef(CeTaskTypes.REPORT, "UUID_1", "COMPONENT_1");
+    LogFileRef ref1bis = new LogFileRef(CeTaskTypes.REPORT, "UUID_1", "COMPONENT_1");
+    LogFileRef ref2 = new LogFileRef(CeTaskTypes.REPORT, "UUID_2", "COMPONENT_1");
+
+    assertThat(ref1.equals(ref1)).isTrue();
+    assertThat(ref1.equals(ref1bis)).isTrue();
+    assertThat(ref1.equals(ref2)).isFalse();
+    assertThat(ref1.equals(null)).isFalse();
+    assertThat(ref1.equals("UUID_1")).isFalse();
+
+    assertThat(ref1.hashCode()).isEqualTo(ref1bis.hashCode());
+  }
+
+  @Test
+  public void getRelativePath() {
+    assertThat(new LogFileRef("TYPE_1", "UUID_1", "COMPONENT_1").getRelativePath()).isEqualTo("TYPE_1/COMPONENT_1/UUID_1.log");
+    assertThat(new LogFileRef("TYPE_1", "UUID_1", null).getRelativePath()).isEqualTo("TYPE_1/UUID_1.log");
+  }
+
+  @Test
+  public void do_not_accept_invalid_task_type() {
+    expectedException.expect(IllegalArgumentException.class);
+    expectedException.expectMessage("'foo/bar' is not a valid filename for Compute Engine logs");
+
+    new LogFileRef("foo/bar", "UUID", null);
+  }
+
+  @Test
+  public void do_not_accept_invalid_uuid() {
+    expectedException.expect(IllegalArgumentException.class);
+    expectedException.expectMessage("'foo/bar' is not a valid filename for Compute Engine logs");
+
+    new LogFileRef("REPORT", "foo/bar", null);
+  }
+
+  @Test
+  public void do_not_accept_invalid_component_uuid() {
+    expectedException.expect(IllegalArgumentException.class);
+    expectedException.expectMessage("'foo/bar' is not a valid filename for Compute Engine logs");
+
+    new LogFileRef("REPORT", "UUID", "foo/bar");
+  }
+
+  @Test
+  public void filename_must_support_uuid() {
+    String uuid = "AU-Tpxb-_iU5OvuD2FLy";
+    assertThat(LogFileRef.requireValidFilename(uuid)).isEqualTo(uuid);
+  }
+}
diff --git a/server/sonar-server/src/test/java/org/sonar/server/computation/ws/ActivityWsActionTest.java b/server/sonar-server/src/test/java/org/sonar/server/computation/ws/ActivityWsActionTest.java
index 8f4e958b9d6..4b63f72bdeb 100644
--- a/server/sonar-server/src/test/java/org/sonar/server/computation/ws/ActivityWsActionTest.java
+++ b/server/sonar-server/src/test/java/org/sonar/server/computation/ws/ActivityWsActionTest.java
@@ -19,8 +19,11 @@
  */
 package org.sonar.server.computation.ws;
 
+import com.google.common.base.Optional;
+import java.io.File;
 import java.util.Collections;
 import java.util.List;
+import org.junit.Before;
 import org.junit.Rule;
 import org.junit.Test;
 import org.sonar.api.server.ws.WebService;
@@ -31,6 +34,8 @@ import org.sonar.db.DbTester;
 import org.sonar.db.ce.CeActivityDto;
 import org.sonar.db.ce.CeQueueDto;
 import org.sonar.db.ce.CeTaskTypes;
+import org.sonar.server.computation.log.CeLogging;
+import org.sonar.server.computation.log.LogFileRef;
 import org.sonar.server.plugins.MimeTypes;
 import org.sonar.server.tester.UserSessionRule;
 import org.sonar.server.ws.TestResponse;
@@ -39,6 +44,9 @@ import org.sonarqube.ws.WsCe;
 
 import static java.util.Arrays.asList;
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Matchers.any;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
 
 public class ActivityWsActionTest {
 
@@ -48,10 +56,16 @@ public class ActivityWsActionTest {
   @Rule
   public DbTester dbTester = DbTester.create(System2.INSTANCE);
 
-  TaskFormatter formatter = new TaskFormatter(dbTester.getDbClient());
+  CeLogging ceLogging = mock(CeLogging.class);
+  TaskFormatter formatter = new TaskFormatter(dbTester.getDbClient(), ceLogging);
   ActivityWsAction underTest = new ActivityWsAction(userSession, dbTester.getDbClient(), formatter);
   WsActionTester tester = new WsActionTester(underTest);
 
+  @Before
+  public void setUp() {
+    when(ceLogging.getFile(any(LogFileRef.class))).thenReturn(Optional.<File>absent());
+  }
+
   @Test
   public void get_all_past_activity() {
     userSession.setGlobalPermissions(UserRole.ADMIN);
@@ -71,9 +85,11 @@ public class ActivityWsActionTest {
     assertThat(activityResponse.getTasks(0).getStatus()).isEqualTo(WsCe.TaskStatus.FAILED);
     assertThat(activityResponse.getTasks(0).getComponentId()).isEqualTo("PROJECT_2");
     assertThat(activityResponse.getTasks(0).getExecutionTimeMs()).isEqualTo(500L);
+    assertThat(activityResponse.getTasks(0).getLogs()).isFalse();
     assertThat(activityResponse.getTasks(1).getId()).isEqualTo("T1");
     assertThat(activityResponse.getTasks(1).getStatus()).isEqualTo(WsCe.TaskStatus.SUCCESS);
     assertThat(activityResponse.getTasks(1).getComponentId()).isEqualTo("PROJECT_1");
+    assertThat(activityResponse.getTasks(1).getLogs()).isFalse();
   }
 
   @Test
diff --git a/server/sonar-server/src/test/java/org/sonar/server/computation/ws/CeWsModuleTest.java b/server/sonar-server/src/test/java/org/sonar/server/computation/ws/CeWsModuleTest.java
index f9c9c7b5ddd..0c557159e26 100644
--- a/server/sonar-server/src/test/java/org/sonar/server/computation/ws/CeWsModuleTest.java
+++ b/server/sonar-server/src/test/java/org/sonar/server/computation/ws/CeWsModuleTest.java
@@ -30,6 +30,6 @@ public class CeWsModuleTest {
   public void verify_count_of_added_components() {
     ComponentContainer container = new ComponentContainer();
     new CeWsModule().configure(container);
-    assertThat(container.size()).isEqualTo(9 + 2 /* injected by ComponentContainer */);
+    assertThat(container.size()).isEqualTo(10 + 2 /* injected by ComponentContainer */);
   }
 }
diff --git a/server/sonar-server/src/test/java/org/sonar/server/computation/ws/LogsWsActionTest.java b/server/sonar-server/src/test/java/org/sonar/server/computation/ws/LogsWsActionTest.java
new file mode 100644
index 00000000000..68148743387
--- /dev/null
+++ b/server/sonar-server/src/test/java/org/sonar/server/computation/ws/LogsWsActionTest.java
@@ -0,0 +1,136 @@
+/*
+ * SonarQube, open source software quality management tool.
+ * Copyright (C) 2008-2014 SonarSource
+ * mailto:contact AT sonarsource DOT com
+ *
+ * SonarQube is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * SonarQube is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+package org.sonar.server.computation.ws;
+
+import com.google.common.base.Optional;
+import java.io.File;
+import java.io.IOException;
+import javax.annotation.Nullable;
+import org.apache.commons.io.FileUtils;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.TemporaryFolder;
+import org.sonar.api.utils.System2;
+import org.sonar.api.web.UserRole;
+import org.sonar.db.DbTester;
+import org.sonar.db.ce.CeQueueDto;
+import org.sonar.db.ce.CeTaskTypes;
+import org.sonar.server.computation.log.CeLogging;
+import org.sonar.server.computation.log.LogFileRef;
+import org.sonar.server.exceptions.ForbiddenException;
+import org.sonar.server.exceptions.NotFoundException;
+import org.sonar.server.plugins.MimeTypes;
+import org.sonar.server.tester.UserSessionRule;
+import org.sonar.server.ws.TestResponse;
+import org.sonar.server.ws.WsActionTester;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+public class LogsWsActionTest {
+
+  @Rule
+  public UserSessionRule userSession = UserSessionRule.standalone();
+
+  @Rule
+  public TemporaryFolder temp = new TemporaryFolder();
+
+  @Rule
+  public DbTester dbTester = DbTester.create(System2.INSTANCE);
+
+  CeLogging ceLogging = mock(CeLogging.class);
+  LogsWsAction underTest = new LogsWsAction(dbTester.getDbClient(), userSession, ceLogging);
+  WsActionTester tester = new WsActionTester(underTest);
+
+  @Test
+  public void return_task_logs_if_available() throws IOException {
+    userSession.setGlobalPermissions(UserRole.ADMIN);
+
+    // task must exist in database
+    insert("TASK_1", null);
+    File logFile = temp.newFile();
+    FileUtils.write(logFile, "{logs}");
+    when(ceLogging.getFile(new LogFileRef(CeTaskTypes.REPORT, "TASK_1", null))).thenReturn(Optional.of(logFile));
+
+    TestResponse response = tester.newRequest()
+      .setParam("taskId", "TASK_1")
+      .execute();
+
+    assertThat(response.getMediaType()).isEqualTo(MimeTypes.TXT);
+    assertThat(response.getInput()).isEqualTo("{logs}");
+  }
+
+  /**
+   * The parameter taskId is present but empty. It's considered as
+   * a valid task which does not exist
+   */
+  @Test(expected = NotFoundException.class)
+  public void return_404_if_task_id_is_empty() {
+    userSession.setGlobalPermissions(UserRole.ADMIN);
+    tester.newRequest()
+      .setParam("taskId", "")
+      .execute();
+  }
+
+  @Test(expected = IllegalArgumentException.class)
+  public void bad_request_if_task_id_is_missing() {
+    userSession.setGlobalPermissions(UserRole.ADMIN);
+    tester.newRequest()
+      .execute();
+  }
+
+  @Test(expected = NotFoundException.class)
+  public void return_404_if_task_logs_are_not_available() {
+    userSession.setGlobalPermissions(UserRole.ADMIN);
+    insert("TASK_1", null);
+    when(ceLogging.getFile(new LogFileRef(CeTaskTypes.REPORT, "TASK_1", null))).thenReturn(Optional.<File>absent());
+
+    tester.newRequest()
+      .setParam("taskId", "TASK_1")
+      .execute();
+  }
+
+  @Test(expected = NotFoundException.class)
+  public void return_404_if_task_does_not_exist() {
+    userSession.setGlobalPermissions(UserRole.ADMIN);
+    tester.newRequest()
+      .setParam("taskId", "TASK_1")
+      .execute();
+  }
+
+  @Test(expected = ForbiddenException.class)
+  public void require_admin_permission() {
+    tester.newRequest()
+      .setParam("taskId", "TASK_1")
+      .execute();
+  }
+
+  private CeQueueDto insert(String taskUuid, @Nullable String componentUuid) {
+    CeQueueDto queueDto = new CeQueueDto();
+    queueDto.setTaskType(CeTaskTypes.REPORT);
+    queueDto.setComponentUuid(componentUuid);
+    queueDto.setUuid(taskUuid);
+    queueDto.setStatus(CeQueueDto.Status.IN_PROGRESS);
+    dbTester.getDbClient().ceQueueDao().insert(dbTester.getSession(), queueDto);
+    dbTester.getSession().commit();
+    return queueDto;
+  }
+}
diff --git a/server/sonar-server/src/test/java/org/sonar/server/computation/ws/ProjectWsActionTest.java b/server/sonar-server/src/test/java/org/sonar/server/computation/ws/ProjectWsActionTest.java
index a088f199a0d..d6a187a8e5e 100644
--- a/server/sonar-server/src/test/java/org/sonar/server/computation/ws/ProjectWsActionTest.java
+++ b/server/sonar-server/src/test/java/org/sonar/server/computation/ws/ProjectWsActionTest.java
@@ -19,6 +19,9 @@
  */
 package org.sonar.server.computation.ws;
 
+import com.google.common.base.Optional;
+import java.io.File;
+import org.junit.Before;
 import org.junit.Rule;
 import org.junit.Test;
 import org.sonar.api.utils.System2;
@@ -28,6 +31,8 @@ import org.sonar.db.DbTester;
 import org.sonar.db.ce.CeActivityDto;
 import org.sonar.db.ce.CeQueueDto;
 import org.sonar.db.ce.CeTaskTypes;
+import org.sonar.server.computation.log.CeLogging;
+import org.sonar.server.computation.log.LogFileRef;
 import org.sonar.server.plugins.MimeTypes;
 import org.sonar.server.tester.UserSessionRule;
 import org.sonar.server.ws.TestResponse;
@@ -35,6 +40,9 @@ import org.sonar.server.ws.WsActionTester;
 import org.sonarqube.ws.WsCe;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Matchers.any;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
 
 public class ProjectWsActionTest {
 
@@ -44,10 +52,16 @@ public class ProjectWsActionTest {
   @Rule
   public DbTester dbTester = DbTester.create(System2.INSTANCE);
 
-  TaskFormatter formatter = new TaskFormatter(dbTester.getDbClient());
+  CeLogging ceLogging = mock(CeLogging.class);
+  TaskFormatter formatter = new TaskFormatter(dbTester.getDbClient(), ceLogging);
   ProjectWsAction underTest = new ProjectWsAction(userSession, dbTester.getDbClient(), formatter);
   WsActionTester tester = new WsActionTester(underTest);
 
+  @Before
+  public void setUp() {
+    when(ceLogging.getFile(any(LogFileRef.class))).thenReturn(Optional.<File>absent());
+  }
+
   @Test
   public void empty_queue_and_empty_activity() {
     userSession.addProjectUuidPermissions(UserRole.USER, "PROJECT_1");
diff --git a/server/sonar-server/src/test/java/org/sonar/server/computation/ws/QueueWsActionTest.java b/server/sonar-server/src/test/java/org/sonar/server/computation/ws/QueueWsActionTest.java
index 6f465f82434..7ae3f6c8256 100644
--- a/server/sonar-server/src/test/java/org/sonar/server/computation/ws/QueueWsActionTest.java
+++ b/server/sonar-server/src/test/java/org/sonar/server/computation/ws/QueueWsActionTest.java
@@ -19,6 +19,9 @@
  */
 package org.sonar.server.computation.ws;
 
+import com.google.common.base.Optional;
+import java.io.File;
+import org.junit.Before;
 import org.junit.Rule;
 import org.junit.Test;
 import org.sonar.api.utils.System2;
@@ -27,6 +30,8 @@ import org.sonar.core.util.Protobuf;
 import org.sonar.db.DbTester;
 import org.sonar.db.ce.CeQueueDto;
 import org.sonar.db.ce.CeTaskTypes;
+import org.sonar.server.computation.log.CeLogging;
+import org.sonar.server.computation.log.LogFileRef;
 import org.sonar.server.plugins.MimeTypes;
 import org.sonar.server.tester.UserSessionRule;
 import org.sonar.server.ws.TestResponse;
@@ -34,6 +39,9 @@ import org.sonar.server.ws.WsActionTester;
 import org.sonarqube.ws.WsCe;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Matchers.any;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
 
 public class QueueWsActionTest {
 
@@ -43,10 +51,16 @@ public class QueueWsActionTest {
   @Rule
   public DbTester dbTester = DbTester.create(System2.INSTANCE);
 
-  TaskFormatter formatter = new TaskFormatter(dbTester.getDbClient());
+  CeLogging ceLogging = mock(CeLogging.class);
+  TaskFormatter formatter = new TaskFormatter(dbTester.getDbClient(), ceLogging);
   CeQueueWsAction underTest = new CeQueueWsAction(userSession, dbTester.getDbClient(), formatter);
   WsActionTester tester = new WsActionTester(underTest);
 
+  @Before
+  public void setUp() {
+    when(ceLogging.getFile(any(LogFileRef.class))).thenReturn(Optional.<File>absent());
+  }
+
   @Test
   public void get_all_queue() {
     userSession.setGlobalPermissions(UserRole.ADMIN);
diff --git a/server/sonar-server/src/test/java/org/sonar/server/computation/ws/TaskFormatterTest.java b/server/sonar-server/src/test/java/org/sonar/server/computation/ws/TaskFormatterTest.java
new file mode 100644
index 00000000000..bfd3377e9b6
--- /dev/null
+++ b/server/sonar-server/src/test/java/org/sonar/server/computation/ws/TaskFormatterTest.java
@@ -0,0 +1,191 @@
+/*
+ * SonarQube, open source software quality management tool.
+ * Copyright (C) 2008-2014 SonarSource
+ * mailto:contact AT sonarsource DOT com
+ *
+ * SonarQube is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * SonarQube is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+package org.sonar.server.computation.ws;
+
+import com.google.common.base.Optional;
+import java.io.IOException;
+import java.util.Date;
+import java.util.List;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.TemporaryFolder;
+import org.mockito.Mockito;
+import org.sonar.api.utils.DateUtils;
+import org.sonar.api.utils.System2;
+import org.sonar.db.DbTester;
+import org.sonar.db.ce.CeActivityDto;
+import org.sonar.db.ce.CeQueueDto;
+import org.sonar.db.ce.CeTaskTypes;
+import org.sonar.db.component.ComponentDto;
+import org.sonar.server.computation.log.CeLogging;
+import org.sonar.server.computation.log.LogFileRef;
+import org.sonarqube.ws.WsCe;
+
+import static java.util.Arrays.asList;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Matchers.any;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+public class TaskFormatterTest {
+
+  @Rule
+  public TemporaryFolder temp = new TemporaryFolder();
+
+  @Rule
+  public DbTester db = DbTester.create(System2.INSTANCE);
+
+  CeLogging ceLogging = mock(CeLogging.class, Mockito.RETURNS_DEEP_STUBS);
+  TaskFormatter underTest = new TaskFormatter(db.getDbClient(), ceLogging);
+
+  @Test
+  public void formatQueue_without_component() {
+    CeQueueDto dto = new CeQueueDto();
+    dto.setUuid("UUID");
+    dto.setTaskType("TYPE");
+    dto.setStatus(CeQueueDto.Status.PENDING);
+    dto.setCreatedAt(1_450_000_000_000L);
+
+    WsCe.Task wsTask = underTest.formatQueue(db.getSession(), dto);
+
+    assertThat(wsTask.getType()).isEqualTo("TYPE");
+    assertThat(wsTask.getId()).isEqualTo("UUID");
+    assertThat(wsTask.getStatus()).isEqualTo(WsCe.TaskStatus.PENDING);
+    assertThat(wsTask.getLogs()).isFalse();
+    assertThat(wsTask.getSubmittedAt()).isEqualTo(DateUtils.formatDateTime(new Date(1_450_000_000_000L)));
+
+    assertThat(wsTask.hasExecutionTimeMs()).isFalse();
+    assertThat(wsTask.hasSubmitterLogin()).isFalse();
+    assertThat(wsTask.hasComponentId()).isFalse();
+    assertThat(wsTask.hasComponentKey()).isFalse();
+    assertThat(wsTask.hasComponentName()).isFalse();
+    assertThat(wsTask.hasFinishedAt()).isFalse();
+  }
+
+  @Test
+  public void formatQueue_with_component_and_other_fields() throws IOException {
+    when(ceLogging.getFile(any(LogFileRef.class))).thenReturn(Optional.of(temp.newFile()));
+    db.getDbClient().componentDao().insert(db.getSession(), new ComponentDto().setUuid("COMPONENT_UUID").setKey("COMPONENT_KEY").setName("Component Name"));
+
+    CeQueueDto dto = new CeQueueDto();
+    dto.setUuid("UUID");
+    dto.setTaskType("TYPE");
+    dto.setStatus(CeQueueDto.Status.IN_PROGRESS);
+    dto.setCreatedAt(1_450_000_000_000L);
+    dto.setStartedAt(1_451_000_000_000L);
+    dto.setComponentUuid("COMPONENT_UUID");
+    dto.setSubmitterLogin("rob");
+
+    WsCe.Task wsTask = underTest.formatQueue(db.getSession(), dto);
+
+    assertThat(wsTask.getType()).isEqualTo("TYPE");
+    assertThat(wsTask.getId()).isEqualTo("UUID");
+    assertThat(wsTask.getComponentId()).isEqualTo("COMPONENT_UUID");
+    assertThat(wsTask.getComponentKey()).isEqualTo("COMPONENT_KEY");
+    assertThat(wsTask.getComponentName()).isEqualTo("Component Name");
+    assertThat(wsTask.getStatus()).isEqualTo(WsCe.TaskStatus.IN_PROGRESS);
+    assertThat(wsTask.getLogs()).isTrue();
+    assertThat(wsTask.getSubmitterLogin()).isEqualTo("rob");
+
+    assertThat(wsTask.hasExecutionTimeMs()).isFalse();
+    assertThat(wsTask.hasFinishedAt()).isFalse();
+  }
+
+  @Test
+  public void formatQueue_do_not_fail_if_component_not_found() throws Exception {
+    CeQueueDto dto = new CeQueueDto();
+    dto.setUuid("UUID");
+    dto.setTaskType("TYPE");
+    dto.setStatus(CeQueueDto.Status.IN_PROGRESS);
+    dto.setCreatedAt(1_450_000_000_000L);
+    dto.setComponentUuid("DOES_NOT_EXIST");
+
+    WsCe.Task wsTask = underTest.formatQueue(db.getSession(), dto);
+
+    assertThat(wsTask.getComponentId()).isEqualTo("DOES_NOT_EXIST");
+    assertThat(wsTask.hasComponentKey()).isFalse();
+    assertThat(wsTask.hasComponentName()).isFalse();
+  }
+
+  @Test
+  public void formatQueues() throws Exception {
+    CeQueueDto dto1 = new CeQueueDto();
+    dto1.setUuid("UUID1");
+    dto1.setTaskType("TYPE1");
+    dto1.setStatus(CeQueueDto.Status.IN_PROGRESS);
+    dto1.setCreatedAt(1_450_000_000_000L);
+
+    CeQueueDto dto2 = new CeQueueDto();
+    dto2.setUuid("UUID2");
+    dto2.setTaskType("TYPE2");
+    dto2.setStatus(CeQueueDto.Status.PENDING);
+    dto2.setCreatedAt(1_451_000_000_000L);
+
+    List<WsCe.Task> wsTasks = underTest.formatQueue(db.getSession(), asList(dto1, dto2));
+    assertThat(wsTasks).extracting("id").containsExactly("UUID1", "UUID2");
+  }
+
+  @Test
+  public void formatActivity() {
+    CeActivityDto dto = newActivity("UUID", "COMPONENT_UUID", CeActivityDto.Status.FAILED);
+
+    WsCe.Task wsTask = underTest.formatActivity(db.getSession(), dto);
+
+    assertThat(wsTask.getType()).isEqualTo(CeTaskTypes.REPORT);
+    assertThat(wsTask.getId()).isEqualTo("UUID");
+    assertThat(wsTask.getStatus()).isEqualTo(WsCe.TaskStatus.FAILED);
+    assertThat(wsTask.getLogs()).isFalse();
+    assertThat(wsTask.getSubmittedAt()).isEqualTo(DateUtils.formatDateTime(new Date(1_450_000_000_000L)));
+    assertThat(wsTask.getExecutionTimeMs()).isEqualTo(500L);
+    assertThat(wsTask.getLogs()).isFalse();
+  }
+
+  @Test
+  public void formatActivity_has_logs() throws IOException {
+    when(ceLogging.getFile(any(LogFileRef.class))).thenReturn(Optional.of(temp.newFile()));
+    CeActivityDto dto = newActivity("UUID", "COMPONENT_UUID", CeActivityDto.Status.FAILED);
+
+    WsCe.Task wsTask = underTest.formatActivity(db.getSession(), dto);
+
+    assertThat(wsTask.getLogs()).isTrue();
+  }
+
+  @Test
+  public void formatActivities() {
+    CeActivityDto dto1 = newActivity("UUID1", "COMPONENT_UUID", CeActivityDto.Status.FAILED);
+    CeActivityDto dto2 = newActivity("UUID2", "COMPONENT_UUID", CeActivityDto.Status.SUCCESS);
+
+    List<WsCe.Task> wsTasks = underTest.formatActivity(db.getSession(), asList(dto1, dto2));
+
+    assertThat(wsTasks).extracting("id").containsExactly("UUID1", "UUID2");
+  }
+
+  private CeActivityDto newActivity(String taskUuid, String componentUuid, CeActivityDto.Status status) {
+    CeQueueDto queueDto = new CeQueueDto();
+    queueDto.setCreatedAt(1_450_000_000_000L);
+    queueDto.setTaskType(CeTaskTypes.REPORT);
+    queueDto.setComponentUuid(componentUuid);
+    queueDto.setUuid(taskUuid);
+    CeActivityDto activityDto = new CeActivityDto(queueDto);
+    activityDto.setStatus(status);
+    activityDto.setExecutionTimeMs(500L);
+    return activityDto;
+  }
+}
diff --git a/server/sonar-server/src/test/java/org/sonar/server/computation/ws/TaskWsActionTest.java b/server/sonar-server/src/test/java/org/sonar/server/computation/ws/TaskWsActionTest.java
index defd028d5cb..31724c81ee5 100644
--- a/server/sonar-server/src/test/java/org/sonar/server/computation/ws/TaskWsActionTest.java
+++ b/server/sonar-server/src/test/java/org/sonar/server/computation/ws/TaskWsActionTest.java
@@ -19,6 +19,9 @@
  */
 package org.sonar.server.computation.ws;
 
+import com.google.common.base.Optional;
+import java.io.File;
+import org.junit.Before;
 import org.junit.Rule;
 import org.junit.Test;
 import org.sonar.api.utils.System2;
@@ -29,6 +32,8 @@ import org.sonar.db.ce.CeActivityDto;
 import org.sonar.db.ce.CeQueueDto;
 import org.sonar.db.ce.CeTaskTypes;
 import org.sonar.db.component.ComponentDto;
+import org.sonar.server.computation.log.CeLogging;
+import org.sonar.server.computation.log.LogFileRef;
 import org.sonar.server.exceptions.NotFoundException;
 import org.sonar.server.plugins.MimeTypes;
 import org.sonar.server.tester.UserSessionRule;
@@ -37,6 +42,9 @@ import org.sonar.server.ws.WsActionTester;
 import org.sonarqube.ws.WsCe;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Matchers.any;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
 
 public class TaskWsActionTest {
 
@@ -46,10 +54,16 @@ public class TaskWsActionTest {
   @Rule
   public DbTester dbTester = DbTester.create(System2.INSTANCE);
 
-  TaskFormatter formatter = new TaskFormatter(dbTester.getDbClient());
+  CeLogging ceLogging = mock(CeLogging.class);
+  TaskFormatter formatter = new TaskFormatter(dbTester.getDbClient(), ceLogging);
   TaskWsAction underTest = new TaskWsAction(dbTester.getDbClient(), formatter, userSession);
   WsActionTester tester = new WsActionTester(underTest);
 
+  @Before
+  public void setUp() {
+    when(ceLogging.getFile(any(LogFileRef.class))).thenReturn(Optional.<File>absent());
+  }
+
   @Test
   public void task_is_in_queue() throws Exception {
     userSession.setGlobalPermissions(UserRole.ADMIN);
@@ -80,6 +94,7 @@ public class TaskWsActionTest {
     assertThat(taskResponse.getTask().getComponentKey()).isEqualTo(project.key());
     assertThat(taskResponse.getTask().getComponentName()).isEqualTo(project.name());
     assertThat(taskResponse.getTask().hasExecutionTimeMs()).isFalse();
+    assertThat(taskResponse.getTask().getLogs()).isFalse();
   }
 
   @Test
@@ -112,6 +127,7 @@ public class TaskWsActionTest {
     assertThat(taskResponse.getTask().getComponentKey()).isEqualTo(project.key());
     assertThat(taskResponse.getTask().getComponentName()).isEqualTo(project.name());
     assertThat(taskResponse.getTask().getExecutionTimeMs()).isEqualTo(500L);
+    assertThat(taskResponse.getTask().getLogs()).isFalse();
   }
 
   @Test(expected = NotFoundException.class)
diff --git a/sonar-application/src/main/java/org/sonar/application/AppLogging.java b/sonar-application/src/main/java/org/sonar/application/AppLogging.java
index 7787e5ea8a3..86afe2f7860 100644
--- a/sonar-application/src/main/java/org/sonar/application/AppLogging.java
+++ b/sonar-application/src/main/java/org/sonar/application/AppLogging.java
@@ -27,7 +27,6 @@ import ch.qos.logback.classic.spi.ILoggingEvent;
 import ch.qos.logback.core.Appender;
 import ch.qos.logback.core.ConsoleAppender;
 import ch.qos.logback.core.FileAppender;
-
 import org.slf4j.LoggerFactory;
 import org.sonar.process.LogbackHelper;
 import org.sonar.process.Props;
@@ -71,7 +70,7 @@ class AppLogging {
   }
 
   private void configureConsole(LoggerContext loggerContext) {
-    ConsoleAppender<ILoggingEvent> consoleAppender = helper.newConsoleAppender(loggerContext, CONSOLE_APPENDER, "%msg%n");
+    ConsoleAppender<ILoggingEvent> consoleAppender = helper.newConsoleAppender(loggerContext, CONSOLE_APPENDER, "%msg%n", null);
     Logger consoleLogger = loggerContext.getLogger(CONSOLE_LOGGER);
     consoleLogger.setAdditive(false);
     consoleLogger.addAppender(consoleAppender);
@@ -96,7 +95,7 @@ class AppLogging {
   }
 
   private void configureRoot(LoggerContext loggerContext) {
-    ConsoleAppender<ILoggingEvent> consoleAppender = helper.newConsoleAppender(loggerContext, "ROOT_CONSOLE", APP_PATTERN);
+    ConsoleAppender<ILoggingEvent> consoleAppender = helper.newConsoleAppender(loggerContext, "ROOT_CONSOLE", APP_PATTERN, null);
     Logger rootLogger = loggerContext.getLogger(Logger.ROOT_LOGGER_NAME);
     rootLogger.setLevel(Level.INFO);
     rootLogger.addAppender(consoleAppender);
diff --git a/sonar-core/src/main/java/org/sonar/core/config/PurgeConstants.java b/sonar-core/src/main/java/org/sonar/core/config/PurgeConstants.java
index 480fa2a684e..84e2ab5bf13 100644
--- a/sonar-core/src/main/java/org/sonar/core/config/PurgeConstants.java
+++ b/sonar-core/src/main/java/org/sonar/core/config/PurgeConstants.java
@@ -22,10 +22,7 @@ package org.sonar.core.config;
 
 public interface PurgeConstants {
 
-  String PLUGIN_KEY = "dbcleaner";
-  String PLUGIN_NAME = "DbCleaner";
   String PROPERTY_CLEAN_DIRECTORY = "sonar.dbcleaner.cleanDirectory";
-
   String HOURS_BEFORE_KEEPING_ONLY_ONE_SNAPSHOT_BY_DAY = "sonar.dbcleaner.hoursBeforeKeepingOnlyOneSnapshotByDay";
   String WEEKS_BEFORE_KEEPING_ONLY_ONE_SNAPSHOT_BY_WEEK = "sonar.dbcleaner.weeksBeforeKeepingOnlyOneSnapshotByWeek";
   String WEEKS_BEFORE_KEEPING_ONLY_ONE_SNAPSHOT_BY_MONTH = "sonar.dbcleaner.weeksBeforeKeepingOnlyOneSnapshotByMonth";
diff --git a/sonar-ws/src/main/gen-java/org/sonarqube/ws/WsCe.java b/sonar-ws/src/main/gen-java/org/sonarqube/ws/WsCe.java
index aa7f58f36e7..797bd2aa902 100644
--- a/sonar-ws/src/main/gen-java/org/sonarqube/ws/WsCe.java
+++ b/sonar-ws/src/main/gen-java/org/sonarqube/ws/WsCe.java
@@ -3851,6 +3851,16 @@ public final class WsCe {
      * <code>optional int64 executionTimeMs = 12;</code>
      */
     long getExecutionTimeMs();
+
+    /**
+     * <code>optional bool logs = 13;</code>
+     */
+    boolean hasLogs();
+
+    /**
+     * <code>optional bool logs = 13;</code>
+     */
+    boolean getLogs();
   }
   /**
    * Protobuf type {@code sonarqube.ws.ce.Task}
@@ -3876,6 +3886,7 @@ public final class WsCe {
       finishedAt_ = "";
       isLastFinished_ = false;
       executionTimeMs_ = 0L;
+      logs_ = false;
     }
 
     @java.lang.Override
@@ -3980,6 +3991,11 @@ public final class WsCe {
               executionTimeMs_ = input.readInt64();
               break;
             }
+            case 104: {
+              bitField0_ |= 0x00001000;
+              logs_ = input.readBool();
+              break;
+            }
           }
         }
       } catch (com.google.protobuf.InvalidProtocolBufferException e) {
@@ -4430,6 +4446,23 @@ public final class WsCe {
       return executionTimeMs_;
     }
 
+    public static final int LOGS_FIELD_NUMBER = 13;
+    private boolean logs_;
+
+    /**
+     * <code>optional bool logs = 13;</code>
+     */
+    public boolean hasLogs() {
+      return ((bitField0_ & 0x00001000) == 0x00001000);
+    }
+
+    /**
+     * <code>optional bool logs = 13;</code>
+     */
+    public boolean getLogs() {
+      return logs_;
+    }
+
     private byte memoizedIsInitialized = -1;
     public final boolean isInitialized() {
       byte isInitialized = memoizedIsInitialized;
@@ -4478,6 +4511,9 @@ public final class WsCe {
       if (((bitField0_ & 0x00000800) == 0x00000800)) {
         output.writeInt64(12, executionTimeMs_);
       }
+      if (((bitField0_ & 0x00001000) == 0x00001000)) {
+        output.writeBool(13, logs_);
+      }
       unknownFields.writeTo(output);
     }
 
@@ -4535,6 +4571,10 @@ public final class WsCe {
         size += com.google.protobuf.CodedOutputStream
           .computeInt64Size(12, executionTimeMs_);
       }
+      if (((bitField0_ & 0x00001000) == 0x00001000)) {
+        size += com.google.protobuf.CodedOutputStream
+          .computeBoolSize(13, logs_);
+      }
       size += unknownFields.getSerializedSize();
       memoizedSerializedSize = size;
       return size;
@@ -4671,6 +4711,8 @@ public final class WsCe {
         bitField0_ = (bitField0_ & ~0x00000400);
         executionTimeMs_ = 0L;
         bitField0_ = (bitField0_ & ~0x00000800);
+        logs_ = false;
+        bitField0_ = (bitField0_ & ~0x00001000);
         return this;
       }
 
@@ -4743,6 +4785,10 @@ public final class WsCe {
           to_bitField0_ |= 0x00000800;
         }
         result.executionTimeMs_ = executionTimeMs_;
+        if (((from_bitField0_ & 0x00001000) == 0x00001000)) {
+          to_bitField0_ |= 0x00001000;
+        }
+        result.logs_ = logs_;
         result.bitField0_ = to_bitField0_;
         onBuilt();
         return result;
@@ -4813,6 +4859,9 @@ public final class WsCe {
         if (other.hasExecutionTimeMs()) {
           setExecutionTimeMs(other.getExecutionTimeMs());
         }
+        if (other.hasLogs()) {
+          setLogs(other.getLogs());
+        }
         this.mergeUnknownFields(other.unknownFields);
         onChanged();
         return this;
@@ -5625,6 +5674,42 @@ public final class WsCe {
         return this;
       }
 
+      private boolean logs_;
+
+      /**
+       * <code>optional bool logs = 13;</code>
+       */
+      public boolean hasLogs() {
+        return ((bitField0_ & 0x00001000) == 0x00001000);
+      }
+
+      /**
+       * <code>optional bool logs = 13;</code>
+       */
+      public boolean getLogs() {
+        return logs_;
+      }
+
+      /**
+       * <code>optional bool logs = 13;</code>
+       */
+      public Builder setLogs(boolean value) {
+        bitField0_ |= 0x00001000;
+        logs_ = value;
+        onChanged();
+        return this;
+      }
+
+      /**
+       * <code>optional bool logs = 13;</code>
+       */
+      public Builder clearLogs() {
+        bitField0_ = (bitField0_ & ~0x00001000);
+        logs_ = false;
+        onChanged();
+        return this;
+      }
+
       // @@protoc_insertion_point(builder_scope:sonarqube.ws.ce.Task)
     }
 
@@ -5717,16 +5802,17 @@ public final class WsCe {
       "asks\030\002 \003(\0132\025.sonarqube.ws.ce.Task\"_\n\017Pro" +
       "jectResponse\022$\n\005queue\030\001 \003(\0132\025.sonarqube." +
       "ws.ce.Task\022&\n\007current\030\002 \001(\0132\025.sonarqube.",
-      "ws.ce.Task\"\224\002\n\004Task\022\n\n\002id\030\001 \001(\t\022\014\n\004type\030" +
+      "ws.ce.Task\"\242\002\n\004Task\022\n\n\002id\030\001 \001(\t\022\014\n\004type\030" +
       "\002 \001(\t\022\023\n\013componentId\030\003 \001(\t\022\024\n\014componentK" +
       "ey\030\004 \001(\t\022\025\n\rcomponentName\030\005 \001(\t\022+\n\006statu" +
       "s\030\006 \001(\0162\033.sonarqube.ws.ce.TaskStatus\022\023\n\013" +
       "submittedAt\030\007 \001(\t\022\026\n\016submitterLogin\030\010 \001(" +
       "\t\022\021\n\tstartedAt\030\t \001(\t\022\022\n\nfinishedAt\030\n \001(\t" +
       "\022\026\n\016isLastFinished\030\013 \001(\010\022\027\n\017executionTim" +
-      "eMs\030\014 \001(\003*Q\n\nTaskStatus\022\013\n\007PENDING\020\000\022\017\n\013" +
-      "IN_PROGRESS\020\001\022\013\n\007SUCCESS\020\002\022\n\n\006FAILED\020\003\022\014" +
-      "\n\010CANCELED\020\004B\032\n\020org.sonarqube.wsB\004WsCeH\001"
+        "eMs\030\014 \001(\003\022\014\n\004logs\030\r \001(\010*Q\n\nTaskStatus\022\013\n" +
+        "\007PENDING\020\000\022\017\n\013IN_PROGRESS\020\001\022\013\n\007SUCCESS\020\002" +
+        "\022\n\n\006FAILED\020\003\022\014\n\010CANCELED\020\004B\032\n\020org.sonarq",
+      "ube.wsB\004WsCeH\001"
     };
     com.google.protobuf.Descriptors.FileDescriptor.InternalDescriptorAssigner assigner =
         new com.google.protobuf.Descriptors.FileDescriptor.    InternalDescriptorAssigner() {
@@ -5776,7 +5862,8 @@ public final class WsCe {
     internal_static_sonarqube_ws_ce_Task_fieldAccessorTable = new
       com.google.protobuf.GeneratedMessage.FieldAccessorTable(
         internal_static_sonarqube_ws_ce_Task_descriptor,
-        new java.lang.String[] { "Id", "Type", "ComponentId", "ComponentKey", "ComponentName", "Status", "SubmittedAt", "SubmitterLogin", "StartedAt", "FinishedAt", "IsLastFinished", "ExecutionTimeMs", });
+      new java.lang.String[] {"Id", "Type", "ComponentId", "ComponentKey", "ComponentName", "Status", "SubmittedAt", "SubmitterLogin", "StartedAt", "FinishedAt", "IsLastFinished",
+        "ExecutionTimeMs", "Logs",});
     org.sonarqube.ws.Common.getDescriptor();
   }
 
diff --git a/sonar-ws/src/main/protobuf/ws-ce.proto b/sonar-ws/src/main/protobuf/ws-ce.proto
index ea423797455..4698ecc1fc7 100644
--- a/sonar-ws/src/main/protobuf/ws-ce.proto
+++ b/sonar-ws/src/main/protobuf/ws-ce.proto
@@ -67,6 +67,7 @@ message Task {
   optional string finishedAt = 10;
   optional bool isLastFinished = 11;
   optional int64 executionTimeMs = 12;
+  optional bool logs = 13;
 }
 
 enum TaskStatus {