CODEWITHSUNDEEP
c#hangfire
Johan
Johan

Reputation: 35194

Hangfire persist local scope

I would like to use Hangfire to create long running fire and forget task. If the web server dies and the background job is retried, I would like it to pick up where it left off.

In the example below, let's say that foo.RetryCount reaches 3 -> server restarts -> Hangfire reruns the job. In this case I would only like to run the task 7 more times (based on MaxAttemps), instead of restarting from zero.

I thought Hangfire persisted the arguments passed to the method in their current state, but as far as I can tell they are reset.

var foo = new Foo { RetryCount = 0, MaxAttemps = 10 };
BackgroundJob.Enqueue(() => RequestAndRetryOnFailure(foo));

void RequestAndRetryOnFailure(Foo foo) 
{
    // make request to server, if fail, wait for a 
    // while and try again later if not foo.MaxAttemps is reached
    foo.RetryCount++;
}

Upvotes: 0

Views: 295

Answers (1)

Jawad
Jawad

Reputation: 11364

I use hangfire extensively for a lot of different actions and have a constant need to reschedule a job that started but couldn't execute due to certain constraints.

The persistency you are referring to happens in the serialized version of the job that's enqeued but no longer kept once it does execute.

What I would recommend is, schedule the job to execute after certain amount if the server is not available. This will also help restart the job if the job is scheduled and hangfire reboots.

var foo = new Foo { RetryCount = 0, MaxAttemps = 10 };
BackgroundJob.Enqueue(() => RequestAndRetryOnFailure(foo));

void RequestAndRetryOnFailure(Foo foo) 
{
    // make request to server, if fail, wait for a 
    // while and try again later if not foo.MaxAttemps is reached
    if (request to server failed) 
    {
        foo.RetryCount ++;
        If (foo.RetryCount < foo.MaxAttempts)
            BackgroundJob.Schedule(RequestAndRetryOnFailure(foo), Timespan.FromSeconds(30));
        else
             return; // do nothing
    }
}

Upvotes: 1

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