service

type Service ¶

type Service interface {
	// Start the service.
	Start() error
	// Stop the Service.
	// Invariants: Usually after this call the Service cannot be started
	// again, you need to build a new Service to do so.
	Close() error

	health.Checkable
}

Service represents a long running service inside the Application.

Typically a Service will leverage utils.StartStopOnce to implement these calls in a safe manner.

Template ¶

Mockable Foo service with a run loop

//go:generate mockery --name Foo --output ../../internal/mocks/ --case=underscore
type (
	// Expose a public interface so we can mock the service.
	Foo interface {
		service.Service

		// ...
	}

	foo struct {
		// ...

		stop chan struct{}
		done chan struct{}

		utils.StartStopOnce
	}
)

var _ Foo = (*foo)(nil)

func NewFoo() Foo {
	f := &foo{
		// ...
	}

	return f
}

func (f *foo) Start() error {
	return f.StartOnce("Foo", func() error {
		go f.run()

		return nil
	})
}

func (f *foo) Close() error {
	return f.StopOnce("Foo", func() error {
		// trigger goroutine cleanup
		close(f.stop)
		// wait for cleanup to complete
		<-f.done
		return nil
	})
}

func (f *foo) run() {
	// signal cleanup completion
	defer close(f.done)

	for {
		select {
		// ...
		case <-f.stop:
			// stop the routine
			return
		}
	}

}