Conditional logging

 * Log condition for log level increase based on conditions. Once one of these
   conditions is met, the required log level is set to debug. This allows to
   debug specific requests, users or apps

 * Supported conditions (setting `log_condition` in `config.php`):
    - `shared_secret`: if a request parameter with the name `log_secret` is set to
                this value the condition is met
    - `users`:  if the current request is done by one of the specified users,
                this condition is met
    - `apps`:   if the log message is invoked by one of the specified apps,
                this condition is met
 * fix unit test and add app log condition test

1 files changed, 65 insertions, 4 deletions

diff --git a/lib/private/log.php b/lib/private/log.php
index 2f15bec433f..840713b2eda 100644
--- a/lib/private/log.php
+++ b/lib/private/log.php
@@ -28,6 +28,7 @@
 namespace OC;
 
 use \OCP\ILogger;
+use OCP\Security\StringUtils;
 
 /**
  * logging utilities
@@ -41,15 +42,29 @@ use \OCP\ILogger;
 
 class Log implements ILogger {
 
+	/** @var string */
 	private $logger;
+	/** @var SystemConfig */
+	private $config;
+
+	/** @var boolean|null cache the result of the log condition check for the request */
+	private $logConditionSatisfied = null;
 
 	/**
 	 * @param string $logger The logger that should be used
+	 * @param SystemConfig $config the system config object
 	 */
-	public function __construct($logger=null) {
+	public function __construct($logger=null, SystemConfig $config=null) {
+		// FIXME: Add this for backwards compatibility, should be fixed at some point probably
+		if($config === null) {
+			$config = \OC::$server->getSystemConfig();
+		}
+
+		$this->config = $config;
+
 		// FIXME: Add this for backwards compatibility, should be fixed at some point probably
 		if($logger === null) {
-			$this->logger = 'OC_Log_'.ucfirst(\OC_Config::getValue('log_type', 'owncloud'));
+			$this->logger = 'OC_Log_'.ucfirst($this->config->getValue('log_type', 'owncloud'));
 			call_user_func(array($this->logger, 'init'));
 		} else {
 			$this->logger = $logger;
@@ -158,8 +173,22 @@ class Log implements ILogger {
 	 * @param array $context
 	 */
 	public function log($level, $message, array $context = array()) {
+		$minLevel = min($this->config->getValue('loglevel', \OC_Log::WARN), \OC_Log::ERROR);
+		$logCondition = $this->config->getValue('log.condition', []);
+
 		if (isset($context['app'])) {
 			$app = $context['app'];
+
+			/**
+			 * check log condition based on the context of each log message
+			 * once this is met -> change the required log level to debug
+			 */
+			if(!empty($logCondition)
+				&& isset($logCondition['apps'])
+				&& in_array($app, $logCondition['apps'], true)) {
+				$minLevel = \OC_Log::DEBUG;
+			}
+
 		} else {
 			$app = 'no app in context';
 		}
@@ -172,9 +201,41 @@ class Log implements ILogger {
 		// interpolate replacement values into the message and return
 		$message = strtr($message, $replace);
 
-		$config = \OC::$server->getSystemConfig();
+		/**
+		 * check for a special log condition - this enables an increased log on
+		 * a per request/user base
+		 */
+		if($this->logConditionSatisfied === null) {
+			// default to false to just process this once per request
+			$this->logConditionSatisfied = false;
+			if(!empty($logCondition)) {
+
+				// check for secret token in the request
+				if(isset($logCondition['shared_secret'])) {
+					$request = \OC::$server->getRequest();
+
+					// if token is found in the request change set the log condition to satisfied
+					if($request && StringUtils::equals($request->getParam('log_secret'), $logCondition['shared_secret'])) {
+						$this->logConditionSatisfied = true;
+					}
+				}
+
+				// check for user
+				if(isset($logCondition['users'])) {
+					$user = \OC::$server->getUserSession()->getUser();
+
+					// if the user matches set the log condition to satisfied
+					if($user !== null && in_array($user->getUID(), $logCondition['users'], true)) {
+						$this->logConditionSatisfied = true;
+					}
+				}
+			}
+		}
 
-		$minLevel = min($config->getValue('loglevel', \OC_Log::WARN), \OC_Log::ERROR);
+		// if log condition is satisfied change the required log level to DEBUG
+		if($this->logConditionSatisfied) {
+			$minLevel = \OC_Log::DEBUG;
+		}
 
 		if ($level >= $minLevel) {
 			$logger = $this->logger;