Add context to future logs.

- Update Logger.php to store context in state
- Add test to ensure it works properly

src/Illuminate/Log/Logger.php

@@ -26,6 +26,13 @@ class Logger implements LoggerInterface
      */
     protected $dispatcher;
 
+    /**
+     * Any context to be added to logs.
+     *
+     * @var array
+     */
+    protected $context = [];
+
     /**
      * Create a new log writer instance.
      *
@@ -161,6 +168,27 @@ public function write($level, $message, array $context = [])
         $this->writeLog($level, $message, $context);
     }
 
+    /**
+     * Adds context to all future logs.
+     *
+     * @param array $context
+     * @return void
+     */
+    public function addContextToLogs($context = [])
+    {
+        $this->context = array_merge([], $this->context, $context);
+    }
+
+    /**
+     * Clears any set context from future logs.
+     *
+     * @return void
+     */
+    public function clearContext()
+    {
+        $this->context = [];
+    }
+
     /**
      * Write a message to the log.
      *
@@ -171,6 +199,8 @@ public function write($level, $message, array $context = [])
      */
     protected function writeLog($level, $message, $context)
     {
+        $context = array_merge([], $this->context, $context);
+
         $this->logger->{$level}($message = $this->formatMessage($message), $context);
 
         $this->fireLogEvent($level, $message, $context);

tests/Log/LogLoggerTest.php

@@ -26,6 +26,16 @@ public function testMethodsPassErrorAdditionsToMonolog()
         $writer->error('foo');
     }
 
+    public function testContextIsAddedToAllSubsequentLogs()
+    {
+        $writer = new Logger($monolog = m::mock(Monolog::class));
+        $writer->addContextToLogs(['bar' => 'baz']);
+
+        $monolog->shouldReceive('error')->once()->with('foo', ['bar' => 'baz']);
+
+        $writer->error('foo');
+    }
+
     public function testLoggerFiresEventsDispatcher()
     {
         $writer = new Logger($monolog = m::mock(Monolog::class), $events = new Dispatcher);