Service types on Humus

Jobs

Mon, 01 Jan 0001 00:00:00 +0000

A job is a process that does one piece of work and exits. The job package turns that work, the run, into a humus.Service that runs it once, stops it on either shutdown signal and records one span around it. The job runs on humus.Main’s defaults, and the run’s error is the exit status, so Kubernetes retries a job that failed or was interrupted and completes one that finished.

The package is job.NewService and nothing else: no App, no Main, no Settings. The design behind everything on this page is in Proposal: jobs and its revision.

Consuming and producing Kafka

Mon, 01 Jan 0001 00:00:00 +0000

The queue/kafka package consumes Kafka topics as a humus.Service, with franz-go. The Service joins a consumer group, dials the brokers through the Setup’s Host, and hands each record to the end user’s queue.Processor, one record at a time per partition, in offset order. The end user’s Init sources its Settings, builds the Service with kafka.NewService, and returns it to humus.Main, whose defaults are a consumer’s.

The package produces records too. A kafka.Producer, which the end user’s Init builds with kafka.NewProducer, produces to one cluster for any Service of the process: a Processor that produces a dead letter or writes to another topic, an HTTP handler that publishes an event, a job. Producing describes it.

Consuming and publishing with RabbitMQ

Mon, 01 Jan 0001 00:00:00 +0000

The queue/rabbitmq package consumes a RabbitMQ queue as a humus.Service, with amqp091-go, RabbitMQ’s own Go client. The Service dials the broker through the Setup’s Host, consumes one queue with manual acks, and hands each delivery to the end user’s queue.Processor, in the order the queue delivered them. The end user’s Init sources its Settings, builds the Service with rabbitmq.NewService, and returns it to humus.Main, whose defaults are a consumer’s.

The package publishes too. A rabbitmq.Publisher, which the end user’s Init builds with rabbitmq.NewPublisher, publishes to the broker with publisher confirms for any Service of the process: a Processor that publishes an event, an HTTP handler, a job. Publishing describes it.

Writing a Kubernetes controller

Mon, 01 Jan 0001 00:00:00 +0000

The kube package writes Kubernetes controllers as humus.Services, with client-go, Kubernetes’ own client, and no controller-runtime. It reaches the API server through the Setup’s Host, declares custom resources as Go values, reflects their CRDs from Go types, and reconciles their objects, or those of Kubernetes’ own kinds, on client-go’s informers, work queue and leader election. The end user’s Init fills a kube.Connection and sources kube.Settings, builds a Client and a Reconciler, and returns the Service that kube.NewController builds to humus.Main, whose defaults fit a controller.