private async Task PollJobs(ITargetBlock <IJob> input, CancellationToken cancellationToken)
{
while (!source.IsCancellationRequested)
{
if (currentJobsActive < thresholdJobsActivation)
{
var jobCount = maxJobsActive - currentJobsActive;
activateJobsCommand.MaxJobsToActivate(jobCount);
try
{
var response = await activateJobsCommand.SendWithRetry(null, cancellationToken);
await HandleActivationResponse(input, response, jobCount);
}
catch (RpcException rpcException)
{
LogRpcException(rpcException);
}
}
else
{
await Task.Delay(pollInterval, cancellationToken);
}
}
}
/// <summary>
/// Opens the configured JobWorker to activate jobs in the given poll interval
/// and handle with the given handler.
/// </summary>
internal void Open()
{
isRunning = true;
var cancellationToken = source.Token;
activateJobsCommand = jobWorkerBuilder.Command;
maxJobsActive = jobWorkerBuilder.Command.Request.MaxJobsToActivate;
// Create options for blocks
var bufferOptions = new DataflowBlockOptions
{
CancellationToken = cancellationToken,
EnsureOrdered = false
};
var executionOptions = new ExecutionDataflowBlockOptions
{
MaxDegreeOfParallelism = jobWorkerBuilder.ThreadCount,
CancellationToken = cancellationToken,
EnsureOrdered = false
};
// Buffer for polled jobs
var input = new BufferBlock <IJob>(bufferOptions);
// Transformblock to process polled jobs
var transformer = new TransformBlock <IJob, IJob>(async activatedJob =>
{
var jobClient = JobClientWrapper.Wrap(jobWorkerBuilder.JobClient);
try
{
await jobHandler(jobClient, activatedJob);
await TryToAutoCompleteJob(jobClient, activatedJob);
}
catch (Exception exception)
{
await FailActivatedJob(jobClient, activatedJob, cancellationToken, exception);
}
finally
{
jobClient.Reset();
}
return(activatedJob);
},
executionOptions);
// Action block to finalize handled tasks
var output = new ActionBlock <IJob>(activatedJob => { currentJobsActive--; },
executionOptions);
// Link blocks
input.LinkTo(transformer);
transformer.LinkTo(output);
// Start polling
Task.Run(async() =>
{
while (!source.IsCancellationRequested)
{
if (currentJobsActive >= maxJobsActive)
{
await Task.Delay(pollInterval);
continue;
}
var jobCount = maxJobsActive - currentJobsActive;
activateJobsCommand.MaxJobsToActivate(jobCount);
try
{
var response = await activateJobsCommand.Send(null, cancellationToken);
logger?.LogDebug(
"Job worker ({worker}) activated {activatedCount} of {requestCount} successfully.",
activateJobsCommand.Request.Worker,
response.Jobs.Count,
jobCount);
foreach (var job in response.Jobs)
{
await input.SendAsync(job);
currentJobsActive++;
}
}
catch (RpcException rpcException)
{
LogRpcException(rpcException);
}
}
},
cancellationToken).ContinueWith(
t => logger?.LogError(t.Exception, "Job polling failed."),
TaskContinuationOptions.OnlyOnFaulted);
var command = jobWorkerBuilder.Command;
logger?.LogDebug(
"Job worker ({worker}) for job type {type} has been opened.",
command.Request.Worker,
command.Request.Type);
}