service

Documentation

Overview

Package service provides simple service framework on top of Module interface. Ready made modules can be found under: github.com/elisasre/go-common/service/module.

Index

• Variables
• func Run(svc Service) error
• func RunAndExit(svc Service)
• type Module
• type Modules
  • func (m Modules) Modules() []Module
• type Service

Examples

• Run

Variables

var ErrPanic = errors.New("panic captured")

Functions

func Run

func Run(svc Service) error

Run runs svc using following control flow:

1. Exec Init() for each module in order. If error is occurred Run returns immediately.
2. Exec Run() for each module in own goroutine.
3. Wait for any Run() function to return. When that happens move to Stop sequence.
4. Exec Stop() for modules in reverse order.
5. Wait for all Run() and Stop() calls to return.
6. Return all errors or nil

Possible panics inside modules are captured to allow graceful shutdown of other modules. Captured panics are converted into errors and ErrPanic is returned.

Example

package main

import (
	"fmt"
	"net/http"
	"os"
	"syscall"
	"time"

	"github.com/elisasre/go-common/service"
	"github.com/elisasre/go-common/service/module/httpserver"
	"github.com/elisasre/go-common/service/module/httpserver/pprof"
	"github.com/elisasre/go-common/service/module/siglistener"
)

func main() {
	// Send SIGINT after 5 second.
	go func() {
		time.Sleep(time.Second * 5)
		syscall.Kill(syscall.Getpid(), syscall.SIGINT) //nolint: errcheck
	}()

	err := service.Run(service.Modules{
		siglistener.New(os.Interrupt),
		httpserver.New(
			httpserver.WithAddr(":6062"),
			pprof.WithProfiling(),
		),
		httpserver.New(
			httpserver.WithServer(&http.Server{ReadHeaderTimeout: time.Second}),
			httpserver.WithAddr(":6060"),
			httpserver.WithHandler(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
				fmt.Fprint(w, "Hello")
			})),
		),
	})
	if err != nil {
		fmt.Println(err)
		return
	}

	fmt.Println("Service exited successfully")
}

Output:

Service exited successfully

func RunAndExit

func RunAndExit(svc Service)

Types

type Module

type Module interface {
	Name() string
	Init() error
	Run() error
	Stop() error
}

type Modules

type Modules []Module

Modules is a convenience type for modules to avoid implementing Service when not necessary.

func (Modules) Modules

func (m Modules) Modules() []Module

type Service

type Service interface {
	Modules() []Module
}

Service is a container for modules.