Issue #3: Queues are now run sequentially and avoid overlapping runs.

.do/run-background-tasks.php

@@ -4,6 +4,8 @@
 
 use Omnipedia\BackgroundTasks\WorkerProcess;
 use React\EventLoop\Loop;
+use React\Promise\ExtendedPromiseInterface;
+use function React\Async\series;
 
 require __DIR__ . '/../vendor/autoload.php';
 
@@ -20,25 +22,39 @@
  (new WorkerProcess('drush cron'))->start();
 });
 
-// Every 5 minutes, process jobs from the image style warmer.
-$loop->addPeriodicTimer(300, function(): void {
- (new WorkerProcess(
- 'drush queue:process image_style_warmer_pregenerator'
- ))->start();
-});
-
-// Every 10 minutes, enqueue and process the warmer queue.
-$loop->addPeriodicTimer(600, function() use ($loop): void {
-
- $loop->futureTick(function(): void {
- (new WorkerProcess('drush warmer:enqueue ' . \implode(',', [
- 'omnipedia_wiki_node_changes',
- 'omnipedia_wiki_node_cdn',
- ])))->start();
- });
+// Every 10 minutes, run queues.
+$loop->addPeriodicTimer(600, function(): void {
+
+ /** @var boolean Static flag indicating whether a run is currently in progress. */
+ static $running = false;
+
+ if ($running === true) {
+ return;
+ }
+
+ $running = true;
+
+ series([
+ function(): ExtendedPromiseInterface {
+ return (new WorkerProcess('drush warmer:enqueue ' . \implode(',', [
+ 'omnipedia_wiki_node_changes',
+ 'omnipedia_wiki_node_cdn',
+ ])))->start()->promise();
+ },
+ function(): ExtendedPromiseInterface {
+ return (new WorkerProcess(
+ 'drush queue:process image_style_warmer_pregenerator'
+ ))->start()->promise();
+ },
+ function(): ExtendedPromiseInterface {
+ return (new WorkerProcess(
+ 'drush queue:process warmer'
+ ))->start()->promise();
+ },
+ ])->always(function() use (&$running) {
+
+ $running = false;
 
- $loop->futureTick(function(): void {
- (new WorkerProcess('drush queue:process warmer'))->start();
  });
 
 });