SquidStd.Workers 0.25.0

<h1 align="center">SquidStd.Workers</h1>

The SquidStd worker runtime. WorkerConsumerService consumes JobRequests from the jobs queue and dispatches each to the IJobHandler registered for its job name (up to MaxConcurrency in parallel), while WorkerHeartbeatService publishes a WorkerHeartbeat on the heartbeat topic every few seconds so a manager can track the fleet. Use it to build worker microservices that pull jobs off a shared queue; pair it with SquidStd.Workers.Manager on the producing side to enqueue jobs and watch heartbeats.

The runtime rides on SquidStd messaging, so a transport must be registered alongside it - in-memory for a single process, RabbitMQ for real multi-process deployments.

Install

dotnet add package SquidStd.Workers

Usage

Register a messaging transport, the worker runtime, and your handlers on the bootstrap container:

using SquidStd.Generators.Workers;
using SquidStd.Messaging.Extensions;
using SquidStd.Services.Core.Extensions;
using SquidStd.Services.Core.Services.Bootstrap;
using SquidStd.Workers.Extensions;

var bootstrap = SquidStdBootstrap.Create(o => o.ConfigName = "myworker");

bootstrap.ConfigureServices(c => c
    .RegisterCoreServices()
    .AddInMemoryMessaging()          // or AddRabbitMqMessaging(...)
    .AddWorkers()
    .RegisterGeneratedJobHandlers()); // source-generated [RegisterJobHandler] registrations

await bootstrap.StartAsync();

A handler implements IJobHandler: it names the job it processes and does the work in HandleAsync, reading string parameters off the JobRequest. [RegisterJobHandler] opts it into generated registration (or register manually with AddJobHandler<T>()):

using SquidStd.Workers.Abstractions.Data;
using SquidStd.Workers.Attributes;
using SquidStd.Workers.Interfaces;

[RegisterJobHandler]
public sealed class ResizeImageHandler : IJobHandler
{
    public string JobName => "resize-image";

    public Task HandleAsync(JobRequest job, CancellationToken cancellationToken)
    {
        var width = job.Parameters["width"];
        // ... do the work ...
        return Task.CompletedTask;
    }
}

On the producing side, SquidStd.Workers.Manager's IJobScheduler (registered with AddWorkerManager()) publishes the JobRequest onto the same queue:

var scheduler = bootstrap.Resolve<IJobScheduler>();
await scheduler.EnqueueAsync("resize-image", new Dictionary<string, string> { ["width"] = "640" });

An unmatched job name raises JobHandlerNotFoundException in the dispatcher.

Configuration

AddWorkers() binds the workers section of the YAML config to WorkersConfig:

workers:
  WorkerId: worker-1
  HeartbeatIntervalSeconds: 10
  MaxConcurrency: 4
  JobQueue: squidstd.workers.jobs
  HeartbeatTopic: squidstd.workers.heartbeat

The channel defaults come from WorkerChannels in SquidStd.Workers.Abstractions, shared with the manager so both sides agree out of the box.

Key types

Related

• Tutorial: Build a worker system
• Article: SquidStd.Workers.Manager
• Article: SquidStd.Workers.Abstractions

License

MIT - part of SquidStd.