hangfire recurring job on every server

Question

I have a situation where I need a recurring job registered with hangfire to run on every server in the cluster.

(The job is to copy some files locally so needs to run on every server regularly)

So far I have tried registering the same job with an id of the server name resulting in n job for n servers:

RecurringJob.AddOrUpdate(Environment.MachineName, () => CopyFiles(Environment.MachineName), Cron.MinuteInterval(_delay));

and the job itself checks if it is the correct server and only does something if it is:

 public static void CopyFiles(string taskId)
 {
        if (string.IsNullOrWhiteSpace(taskId) || !taskId.Equals(Environment.MachineName))
        {
            return;
        }

        // do stuff here if it matches our taskname
}

The problem with this is that all jobs executes on the first server to come along, is marked as complete and as a result is not executed by the other servers.

Is there any way to ensure that the job runs on all servers?

or is there a way to ensure that only one server can process a given job? i.e. target the job at the server that created it

Pedant

I was looking for the opposite of this, but you question helped me as you said its possible. – Mature

Answer 1

Found an answer using this link.

Simply assign the job to a queue that is specific to the server you want it processing on.

So I changed my enqueue to:

RecurringJob.AddOrUpdate(Environment.MachineName, 
  () => CopyFiles(Environment.MachineName),
  Cron.MinuteInterval(_delay), 
  queue: Environment.MachineName.ToLower(CultureInfo.CurrentCulture));

And when I start my server I do this:

_backgroundJobServer = new BackgroundJobServer(new BackgroundJobServerOptions 
                           {
                               Queues = new[] { Environment.MachineName.ToLower() } 
                           });

Pedant

Be careful, when this job retries it goes back to "default" queue! Unless you use an attribute as shown here: github.com/HangfireIO/Hangfire/pull/502 – Packton