Introduce Resque_Job_PID so a process PID can be obtained.

Author: mateusz

HOWITWORKS.md

@@ -101,47 +101,50 @@ How do the workers process the queues?
         8. `Resque_Job->fail()` returns control to the worker (still in
            `Resque_Worker::work()`) without a value
       * Job
-        1. The job calls `Resque_Worker->perform()` with the `Resque_Job` as its
+        1. `Resque_Job_PID` is created, registering the PID of the actual process
+            doing the job.
+        2. The job calls `Resque_Worker->perform()` with the `Resque_Job` as its
            only argument.
-        2. `Resque_Worker->perform()` sets up a `try...catch` block so it can
+        3. `Resque_Worker->perform()` sets up a `try...catch` block so it can
            properly handle exceptions by marking jobs as failed (by calling
            `Resque_Job->fail()`, as above)
-        3. Inside the `try...catch`, `Resque_Worker->perform()` triggers an
+        4. Inside the `try...catch`, `Resque_Worker->perform()` triggers an
            `afterFork` event
-        4. Still inside the `try...catch`, `Resque_Worker->perform()` calls
+        5. Still inside the `try...catch`, `Resque_Worker->perform()` calls
            `Resque_Job->perform()` with no arguments
-        5. `Resque_Job->perform()` calls `Resque_Job->getInstance()` with no
+        6. `Resque_Job->perform()` calls `Resque_Job->getInstance()` with no
            arguments
-        6. If `Resque_Job->getInstance()` has already been called, it returns the
+        7. If `Resque_Job->getInstance()` has already been called, it returns the
            existing instance; otherwise:
-        7. `Resque_Job->getInstance()` checks that the job's class (type) exists
+        8. `Resque_Job->getInstance()` checks that the job's class (type) exists
            and has a `perform()` method; if not, in either case, it throws an
            exception which will be caught by `Resque_Worker->perform()`
-        8. `Resque_Job->getInstance()` creates an instance of the job's class, and
+        9. `Resque_Job->getInstance()` creates an instance of the job's class, and
            initializes it with a reference to the `Resque_Job` itself, the job's
            arguments (which it gets by calling `Resque_Job->getArguments()`, which
            in turn simply returns the value of `args[0]`, or an empty array if no
            arguments were passed), and the queue name
-        9. `Resque_Job->getInstance()` returns control, along with the job class
+        10. `Resque_Job->getInstance()` returns control, along with the job class
            instance, to `Resque_Job->perform()`
-        10. `Resque_Job->perform()` sets up its own `try...catch` block to handle
+        11. `Resque_Job->perform()` sets up its own `try...catch` block to handle
             `Resque_Job_DontPerform` exceptions; any other exceptions are passed
             up to `Resque_Worker->perform()`
-        11. `Resque_Job->perform()` triggers a `beforePerform` event
-        12. `Resque_Job->perform()` calls `setUp()` on the instance, if it exists
-        13. `Resque_Job->perform()` calls `perform()` on the instance
-        14. `Resque_Job->perform()` calls `tearDown()` on the instance, if it
+        12. `Resque_Job->perform()` triggers a `beforePerform` event
+        13. `Resque_Job->perform()` calls `setUp()` on the instance, if it exists
+        14. `Resque_Job->perform()` calls `perform()` on the instance
+        15. `Resque_Job->perform()` calls `tearDown()` on the instance, if it
             exists
-        15. `Resque_Job->perform()` triggers an `afterPerform` event
-        16. The `try...catch` block ends, suppressing `Resque_Job_DontPerform`
+        16. `Resque_Job->perform()` triggers an `afterPerform` event
+        17. The `try...catch` block ends, suppressing `Resque_Job_DontPerform`
             exceptions by returning control, and the value `FALSE`, to
             `Resque_Worker->perform()`; any other situation returns the value
             `TRUE` along with control, instead
-        17. The `try...catch` block in `Resque_Worker->perform()` ends
-        18. `Resque_Worker->perform()` updates the job status from `RUNNING` to
+        18. The `try...catch` block in `Resque_Worker->perform()` ends
+        19. `Resque_Worker->perform()` updates the job status from `RUNNING` to
             `COMPLETE`, then returns control, with no value, to the worker (again
             still in `Resque_Worker::work()`)
-        19. `Resque_Worker::work()` calls `exit(0)` to terminate the job process
+        20. `Resque_Job_PID()` is removed, the forked process will terminate soon
+        21. `Resque_Worker::work()` calls `exit(0)` to terminate the job process
             cleanly
       * SPECIAL CASE: Non-forking OS (Windows)
         1. Same as the job above, except it doesn't call `exit(0)` when done

README.md

@@ -193,6 +193,19 @@ or failed, and are then automatically expired. A status can also
 forcefully be expired by calling the `stop()` method on a status
 class.
 
+### Obtaining job PID ###
+
+You can obtain the PID of the actual process doing the work through `Resque_Job_PID`. On a forking OS this will be the
+PID of the forked process.
+
+CAUTION: on a non-forking OS, the PID returned will be of the worker itself.
+
+```php
+echo Resque_Job_PID::get($token);
+```
+
+Function returns `0` if the `perform` hasn't started yet, or if it has already ended.
+
 ## Workers ##
 
 Workers work in the exact same way as the Ruby workers. For complete

lib/Resque/Job/PID.php

@@ -0,0 +1,41 @@
+<?php
+/**
+ * PID tracker for the forked worker job.
+ *
+ * @package		Resque/Job
+ * @author		Chris Boulton <[email protected]>
+ * @license		http://www.opensource.org/licenses/mit-license.php
+ */
+class Resque_Job_PID
+{
+	/**
+	 * Create a new PID tracker item for the supplied job ID.
+	 *
+	 * @param string $id The ID of the job to track the PID of.
+	 */
+	public static function create($id)
+	{
+		Resque::redis()->set('job:' . $id . ':pid', (string)getmypid());
+	}
+
+	/**
+	 * Fetch the PID for the process actually executing the job.
+	 *
+	 * @param string $id The ID of the job to get the PID of.
+	 *
+	 * @return int PID of the process doing the job (on non-forking OS, PID of the worker, otherwise forked PID).
+	 */
+	public static function get($id)
+	{
+		return (int)Resque::redis()->get('job:' . $id . ':pid');
+	}
+
+	/**
+	 * Remove the PID tracker for the job.
+	 */
+	public static function del($id)
+	{
+		Resque::redis()->del('job:' . $id . ':pid');
+	}
+}
+

lib/Resque/Worker.php

@@ -199,7 +199,17 @@ public function work($interval = Resque::DEFAULT_INTERVAL, $blocking = false)
 				$status = 'Processing ' . $job->queue . ' since ' . strftime('%F %T');
 				$this->updateProcLine($status);
 				$this->logger->log(Psr\Log\LogLevel::INFO, $status);
+
+				if(!empty($job->payload['id'])) {
+					Resque_Job_PID::create($job->payload['id']);
+				}
+
 				$this->perform($job);
+
+				if(!empty($job->payload['id'])) {
+					Resque_Job_PID::del($job->payload['id']);
+				}
+
 				if ($this->child === 0) {
 					exit(0);
 				}
@@ -394,6 +404,13 @@ public function shutdownNow()
 		$this->killChild();
 	}
 
+	/**
+	 * @return int Child process PID.
+	 */
+	public function getChildPID() {
+		return $this->child;
+	}
+
 	/**
 	 * Kill a forked child job immediately. The job it is processing will not
 	 * be completed.

test/Resque/Tests/JobPIDTest.php

@@ -0,0 +1,47 @@
+<?php
+/**
+ * Resque_Job_PID tests.
+ *
+ * @package		Resque/Tests
+ * @author		Chris Boulton <[email protected]>
+ * @license		http://www.opensource.org/licenses/mit-license.php
+ */
+class Resque_Tests_JobPIDTest extends Resque_Tests_TestCase
+{
+    /**
+     * @var \Resque_Worker
+     */
+    protected $worker;
+
+	public function setUp()
+	{
+		parent::setUp();
+
+		// Register a worker to test with
+		$this->worker = new Resque_Worker('jobs');
+		$this->worker->setLogger(new Resque_Log());
+	}
+
+	public function testQueuedJobDoesNotReturnPID()
+	{
+		$token = Resque::enqueue('jobs', 'Test_Job', null, true);
+		$this->assertEquals(0, Resque_Job_PID::get($token));
+	}
+
+	public function testRunningJobReturnsPID()
+	{
+		// Cannot use InProgress_Job on non-forking OS.
+		if(!function_exists('pcntl_fork')) return;
+
+		$token = Resque::enqueue('jobs', 'InProgress_Job', null, true);
+		$this->worker->work(0);
+		$this->assertNotEquals(0, Resque_Job_PID::get($token));
+	}
+
+	public function testFinishedJobDoesNotReturnPID()
+	{
+		$token = Resque::enqueue('jobs', 'Test_Job', null, true);
+		$this->worker->work(0);
+		$this->assertEquals(0, Resque_Job_PID::get($token));
+	}
+}

test/bootstrap.php

@@ -109,6 +109,24 @@ public function perform()
 	}
 }
 
+/**
+ * This job exits the forked worker process, which simulates the job being (forever) in progress,
+ * so that we can verify the state of the system for "running jobs". Does not work on a non-forking OS.
+ *
+ * CAUTION Use this test job only with Worker::work, i.e. only when you actually trigger the fork in tests.
+ */
+class InProgress_Job
+{
+	public function perform()
+	{
+		if(!function_exists('pcntl_fork')) {
+			// We can't lose the worker on a non-forking OS.
+			throw new Failing_Job_Exception('Do not use InProgress_Job for tests on non-forking OS!');
+		}
+		exit(0);
+	}
+}
+
 class Test_Job_Without_Perform_Method
 {