delay compression routine by random interval (fixes #21)

Dan Butvinik · Dan Butvinik · commit c12d4dabdebd · 2017-10-14T00:46:25.000Z
diff --git a/ImgBot.Function/Functions.cs b/ImgBot.Function/Functions.cs
@@ -11,6 +11,8 @@ namespace ImgBot.Function
 {
     public static class Functions
     {
+        private static Random s_random = new Random();
+
         [FunctionName("imageupdatemessage")]
         public static async Task RunImageUpdateMessage(
             [QueueTrigger("imageupdatemessage")]ImageUpdateMessage imageUpdateMessage,
@@ -84,6 +86,12 @@ public static async Task RunInstallationMessage(
                 RepoOwner = installationMessage.Owner,
             };
 
+            // getting duplicate work happening at the same exact time in multiple threads
+            // the most common case is install and add events on the same repo when the queue is asleep
+            // the queue wakes up and dequeues both messages at the same time in 2 threads
+            // wait a random amount of seconds so that one will win
+            System.Threading.Thread.Sleep(TimeSpan.FromSeconds(s_random.Next(0, 20)));
+
             await CompressImages.RunAsync(compressImagesParameters);
         }
     }

Original file line number	Diff line number	Diff line change
`@@ -11,6 +11,8 @@ namespace ImgBot.Function`
`11`	`11`	`{`
`12`	`12`	`public static class Functions`
`13`	`13`	`{`
	`14`	`+ private static Random s_random = new Random();`
	`15`	`+`
`14`	`16`	`[FunctionName("imageupdatemessage")]`
`15`	`17`	`public static async Task RunImageUpdateMessage(`
`16`	`18`	`[QueueTrigger("imageupdatemessage")]ImageUpdateMessage imageUpdateMessage,`
`@@ -84,6 +86,12 @@ public static async Task RunInstallationMessage(`
`84`	`86`	`RepoOwner = installationMessage.Owner,`
`85`	`87`	`};`
`86`	`88`
	`89`	`+ // getting duplicate work happening at the same exact time in multiple threads`
	`90`	`+ // the most common case is install and add events on the same repo when the queue is asleep`
	`91`	`+ // the queue wakes up and dequeues both messages at the same time in 2 threads`
	`92`	`+ // wait a random amount of seconds so that one will win`
	`93`	`+ System.Threading.Thread.Sleep(TimeSpan.FromSeconds(s_random.Next(0, 20)));`
	`94`	`+`
`87`	`95`	`await CompressImages.RunAsync(compressImagesParameters);`
`88`	`96`	`}`
`89`	`97`	`}`