Graceful shutdown

[[TOC]]

Goal

This library aims to make graceful shutdown easy and safe. It has some helpers to make setup easier.

Helpers

Graceful

• GRPCServer - pass *grpc.Server and it will stop it gracefully. New connections are not accepted, blocks until existing connections finish.
• HTTPServer - pass *http.Server and it will stop it gracefully. New connections are not accepted, blocks until existing connections finish.
• PubSubTopic - pass *pubsub.Topic and it will stop it gracefully. Publishes all remaining messages to publish.
• Centrifuge - pass *centrifuge.Node and it will stop it gracefully. New connections are not accepted, existing ones are disconnected with shutdown reason.
• Redis - pass *redis.Client and it will stop it gracefully.
• Logger - pass *zap.SugaredLogger and it will flush all buffered messages. Useful to ensure no logs are missing in logs explorer.
• WaitGroup - pass *sync.WaitGroup and it will wait for waitgroup to finish.
• Tracer - exports all remaining tracing spans.

Graceless

• Context - pass context.CancelFunc and it will be called. Useful to cancel root context after all servers were stopped to ensure nothing is still invoking.
• GRPCClient - pass *grpc.ClientConn and it will stop it.
• Spanner - pass *spanner.Client and it will close all connections.

Example

package main

import (
	"context"
	"os"
	"runtime"
	"syscall"
	"time"

	"github.com/go-redis/redis/v9"
	"gitlab.com/picnic-app/backend/libs/golang/graceful"
)

func main() {
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	rc := redis.NewClient(&redis.Options{})
	rc.Get(ctx, "blabla")

	shutdown := graceful.New(
		&graceful.ShutdownManagerOptions{
			Timeout: time.Second * 15,
		},
		graceful.Parallel(
			&graceful.ParallelShutdownOptions{
				Name:    "servers",
				Timeout: time.Second * 30,
			},
		),
		graceful.Parallel(
			&graceful.ParallelShutdownOptions{
				Name:    "long tasks",
				Timeout: time.Second * 5,
			},
		),
		graceful.Context(cancel),
		graceful.Logger(nil),
		graceful.Parallel(
			&graceful.ParallelShutdownOptions{
				Name:    "clients",
				Timeout: time.Second * 5,
			},
			graceful.Redis(rc),
		),
	)
	shutdown.RegisterSignals(os.Interrupt, syscall.SIGTERM)

	time.Sleep(time.Second * 5)
	_ = shutdown.Shutdown(context.Background())

	for {
		runtime.Gosched()
	}
}

Configure access to private modules on gitlab

This notion page explains how to configure local environment to work with private modules stored in Picnic gitlab repository.