From 1f9d2050434f7ad25e06f44c1842dd365d6ec539 Mon Sep 17 00:00:00 2001
From: Shawn Pearce <spearce@spearce.org>
Date: Fri, 4 Dec 2015 15:02:09 -0800
Subject: [PATCH] Ketch: Intercept push and route it through Ketch

Capture commands and pass to the in-process KetchLeader, allowing
it to replicate to followers.

Change-Id: I25dfeb2a93821af65354337f391480a72bae2210
---
 .../jgit/internal/ketch/KetchText.properties  |   5 +
 .../jgit/internal/ketch/KetchLeader.java      |   2 +-
 .../jgit/internal/ketch/KetchPreReceive.java  | 155 ++++++++++++++++++
 .../jgit/internal/ketch/KetchText.java        |   5 +
 4 files changed, 166 insertions(+), 1 deletion(-)
 create mode 100644 org.eclipse.jgit/src/org/eclipse/jgit/internal/ketch/KetchPreReceive.java

diff --git a/org.eclipse.jgit/resources/org/eclipse/jgit/internal/ketch/KetchText.properties b/org.eclipse.jgit/resources/org/eclipse/jgit/internal/ketch/KetchText.properties
index 4984dda74d..3817fb93cc 100644
--- a/org.eclipse.jgit/resources/org/eclipse/jgit/internal/ketch/KetchText.properties
+++ b/org.eclipse.jgit/resources/org/eclipse/jgit/internal/ketch/KetchText.properties
@@ -1,7 +1,12 @@
+accepted=accepted.
 cannotFetchFromLocalReplica=cannot fetch from LocalReplica
+failed=failed!
 leaderFailedToStore=leader failed to store
 localReplicaRequired=LocalReplica instance is required
 mismatchedTxnNamespace=mismatched txnNamespace; expected {0} found {1}
 outsideTxnNamespace=ref {0} is outside of txnNamespace {1}
+proposingUpdates=Proposing updates
 queuedProposalFailedToApply=queued proposal failed to apply
+starting=starting!
 unsupportedVoterCount=unsupported voter count {0}, expected one of {1}
+waitingForQueue=Waiting for queue
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/internal/ketch/KetchLeader.java b/org.eclipse.jgit/src/org/eclipse/jgit/internal/ketch/KetchLeader.java
index 851d433c4e..3bcd6bcb24 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/internal/ketch/KetchLeader.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/internal/ketch/KetchLeader.java
@@ -86,7 +86,7 @@ import org.slf4j.LoggerFactory;
  * leader is discarded.
  * <p>
  * In Ketch all push requests are issued through the leader. The steps are as
- * follows:
+ * follows (see {@link KetchPreReceive} for an example):
  * <ul>
  * <li>Create a {@link Proposal} with the
  * {@link org.eclipse.jgit.transport.ReceiveCommand}s that represent the push.
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/internal/ketch/KetchPreReceive.java b/org.eclipse.jgit/src/org/eclipse/jgit/internal/ketch/KetchPreReceive.java
new file mode 100644
index 0000000000..1b4307f3fb
--- /dev/null
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/internal/ketch/KetchPreReceive.java
@@ -0,0 +1,155 @@
+/*
+ * Copyright (C) 2016, Google Inc.
+ * and other copyright owners as documented in the project's IP log.
+ *
+ * This program and the accompanying materials are made available
+ * under the terms of the Eclipse Distribution License v1.0 which
+ * accompanies this distribution, is reproduced below, and is
+ * available at http://www.eclipse.org/org/documents/edl-v10.php
+ *
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or
+ * without modification, are permitted provided that the following
+ * conditions are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above
+ *   copyright notice, this list of conditions and the following
+ *   disclaimer in the documentation and/or other materials provided
+ *   with the distribution.
+ *
+ * - Neither the name of the Eclipse Foundation, Inc. nor the
+ *   names of its contributors may be used to endorse or promote
+ *   products derived from this software without specific prior
+ *   written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+ * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+ * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+package org.eclipse.jgit.internal.ketch;
+
+import static java.util.concurrent.TimeUnit.MILLISECONDS;
+import static java.util.concurrent.TimeUnit.SECONDS;
+import static org.eclipse.jgit.internal.ketch.Proposal.State.EXECUTED;
+import static org.eclipse.jgit.internal.ketch.Proposal.State.QUEUED;
+import static org.eclipse.jgit.transport.ReceiveCommand.Result.NOT_ATTEMPTED;
+import static org.eclipse.jgit.transport.ReceiveCommand.Result.REJECTED_OTHER_REASON;
+
+import java.io.IOException;
+import java.util.Collection;
+
+import org.eclipse.jgit.internal.JGitText;
+import org.eclipse.jgit.transport.PreReceiveHook;
+import org.eclipse.jgit.transport.ProgressSpinner;
+import org.eclipse.jgit.transport.ReceiveCommand;
+import org.eclipse.jgit.transport.ReceivePack;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * PreReceiveHook for handling push traffic in a Ketch system.
+ * <p>
+ * Install an instance on {@link ReceivePack} to capture the commands and other
+ * connection state and relay them through the {@link KetchLeader}, allowing the
+ * leader to gain consensus about the new reference state.
+ */
+public class KetchPreReceive implements PreReceiveHook {
+	private static final Logger log = LoggerFactory.getLogger(KetchPreReceive.class);
+
+	private final KetchLeader leader;
+
+	/**
+	 * Construct a hook executing updates through a {@link KetchLeader}.
+	 *
+	 * @param leader
+	 *            leader for this repository.
+	 */
+	public KetchPreReceive(KetchLeader leader) {
+		this.leader = leader;
+	}
+
+	@Override
+	public void onPreReceive(ReceivePack rp, Collection<ReceiveCommand> cmds) {
+		cmds = ReceiveCommand.filter(cmds, NOT_ATTEMPTED);
+		if (cmds.isEmpty()) {
+			return;
+		}
+
+		try {
+			Proposal proposal = new Proposal(rp.getRevWalk(), cmds)
+				.setPushCertificate(rp.getPushCertificate())
+				.setAuthor(rp.getRefLogIdent())
+				.setMessage("push"); //$NON-NLS-1$
+			leader.queueProposal(proposal);
+			if (proposal.isDone()) {
+				// This failed fast, e.g. conflict or bad precondition.
+				return;
+			}
+
+			ProgressSpinner spinner = new ProgressSpinner(
+					rp.getMessageOutputStream());
+			if (proposal.getState() == QUEUED) {
+				waitForQueue(proposal, spinner);
+			}
+			if (!proposal.isDone()) {
+				waitForPropose(proposal, spinner);
+			}
+		} catch (IOException | InterruptedException e) {
+			String msg = JGitText.get().transactionAborted;
+			for (ReceiveCommand cmd : cmds) {
+				if (cmd.getResult() == NOT_ATTEMPTED) {
+					cmd.setResult(REJECTED_OTHER_REASON, msg);
+				}
+			}
+			log.error(msg, e);
+		}
+	}
+
+	private void waitForQueue(Proposal proposal, ProgressSpinner spinner)
+			throws InterruptedException {
+		spinner.beginTask(KetchText.get().waitingForQueue, 1, SECONDS);
+		while (!proposal.awaitStateChange(QUEUED, 250, MILLISECONDS)) {
+			spinner.update();
+		}
+		switch (proposal.getState()) {
+		case RUNNING:
+		default:
+			spinner.endTask(KetchText.get().starting);
+			break;
+
+		case EXECUTED:
+			spinner.endTask(KetchText.get().accepted);
+			break;
+
+		case ABORTED:
+			spinner.endTask(KetchText.get().failed);
+			break;
+		}
+	}
+
+	private void waitForPropose(Proposal proposal, ProgressSpinner spinner)
+			throws InterruptedException {
+		spinner.beginTask(KetchText.get().proposingUpdates, 2, SECONDS);
+		while (!proposal.await(250, MILLISECONDS)) {
+			spinner.update();
+		}
+		spinner.endTask(proposal.getState() == EXECUTED
+				? KetchText.get().accepted
+				: KetchText.get().failed);
+	}
+}
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/internal/ketch/KetchText.java b/org.eclipse.jgit/src/org/eclipse/jgit/internal/ketch/KetchText.java
index a4e42bb099..da85c0112d 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/internal/ketch/KetchText.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/internal/ketch/KetchText.java
@@ -54,11 +54,16 @@ public class KetchText extends TranslationBundle {
 	}
 
 	// @formatter:off
+	/***/ public String accepted;
 	/***/ public String cannotFetchFromLocalReplica;
+	/***/ public String failed;
 	/***/ public String leaderFailedToStore;
 	/***/ public String localReplicaRequired;
 	/***/ public String mismatchedTxnNamespace;
 	/***/ public String outsideTxnNamespace;
+	/***/ public String proposingUpdates;
 	/***/ public String queuedProposalFailedToApply;
+	/***/ public String starting;
 	/***/ public String unsupportedVoterCount;
+	/***/ public String waitingForQueue;
 }
-- 
2.39.5