Add graceful shutdown

Author: Sommer Matthias (IFAG IT DSA RD CM / External)

README.md

@@ -5,19 +5,22 @@ Uses a controller/repository pattern to handle typical CRUD actions.
 Exposes the controller methods via HTTP endpoints.
 
 
-## Install dependencies
+## Dependencies
 
 ```bash
-go get -d ./...
+go mod download
 ```
 
-## Generate mocks
+## Mocks
+
+Mocks are generated with (Mockery)[https://github.com/vektra/mockery].
+Put the executable under $GOPATH/bin/mockery and create mocks for interfaces with
 
 ```bash
 %GOPATH%/bin/mockery -all -case=underscore -inpkg
 ```
 
-## Go Lint
+## Lint
 
 1. Get golangci-lint from [Github](https://github.com/golangci/golangci-lint).
 2. Follow the steps under [Editor Integration](https://github.com/golangci/golangci-lint#editor-integration).

api/router.go

@@ -1,9 +1,11 @@
 package api
 
 import (
+	"context"
 	"golang-microservice-template/pizza"
 	. "golang-microservice-template/utils"
 	"net/http"
+	"time"
 
 	"github.com/labstack/echo"
 	"github.com/labstack/echo/middleware"
@@ -17,6 +19,8 @@ type Router interface {
 	Index(echo.Context) error
 	// Start starts listening for incoming requests on the specified address/port.
 	Start(address string) error
+	// Shutdown is waiting some seconds to stop the server gracefully and to release resources.
+	Shutdown(ctx context.Context) error
 }
 
 type router struct {
@@ -73,3 +77,12 @@ func (r *router) setRoutes(echo *echo.Echo) {
 	pizza.PATCH("/:name", controller.Update)
 	pizza.DELETE("/:name", controller.Delete)
 }
+
+func (router *Router) Shutdown() {
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	defer cancel()
+
+	if err := router.echo.Shutdown(ctx); err != nil {
+		Log.Fatal(err)
+	}
+}

main.go

@@ -3,7 +3,10 @@ package main
 import (
 	"golang-microservice-template/api"
 	. "golang-microservice-template/utils"
+	"os"
+	"os/signal"
 	"strconv"
+	"syscall"
 )
 
 const (
@@ -21,7 +24,13 @@ func main() {
 		port = localPort
 	}
 
-	Log.Fatal(router.Start(":" + strconv.Itoa(port)))
+	go func() {
+		Log.Fatal(router.Start(":" + strconv.Itoa(port)))
+	}()
 
-	Log.Infof("[PizzaService] Started")
+	done := make(chan os.Signal, 1)
+	signal.Notify(done, os.Interrupt, syscall.SIGINT, syscall.SIGTERM, syscall.SIGQUIT, syscall.SIGABRT)
+	<-done
+
+	router.Shutdown()
 }

pizza/controller.go

@@ -12,6 +12,11 @@ const (
 	PathParamName = "name"
 )
 
+// errors
+var (
+	ErrParamNameMissing = "missing pizza name in path"
+)
+
 // Controller handles all requests related to pizza data.
 type Controller interface {
 	// Add creates a new pizza.
@@ -50,7 +55,7 @@ func (c *controller) Add(ctx echo.Context) error {
 
 	found, err := c.repository.FindByName(dto.Name)
 	if found != nil {
-		return Errorf(ErrorTypeConflict, "a pizza with the name '%s' already exists", dto.Name)
+		return Errorf(ErrorTypeConflict, ErrPizzaNameTaken, dto.Name)
 	} else if err != nil {
 		Log.Debug(err)
 	}
@@ -101,7 +106,7 @@ func (c *controller) GetByName(ctx echo.Context) error {
 	if err != nil {
 		return Error(err, ErrorTypeDatabase)
 	} else if pizza == nil {
-		return Errorf(ErrorTypeResourceNotFound, "pizza '%s' could not be found", name)
+		return Errorf(ErrorTypeResourceNotFound, ErrPizzaNotFound, name)
 	}
 
 	dto, err := pizza.ConvertToDto()
@@ -129,7 +134,7 @@ func (c *controller) Update(ctx echo.Context) error {
 
 	pizza, _ := c.repository.FindByName(name)
 	if pizza == nil {
-		return Errorf(ErrorTypeResourceNotFound, "there is no pizza with name '%s'", name)
+		return Errorf(ErrorTypeResourceNotFound, ErrPizzaNotFound, name)
 	}
 
 	pizza, err = dto.ConvertToModel()
@@ -160,7 +165,7 @@ func (c *controller) Delete(ctx echo.Context) error {
 	if err != nil {
 		return Error(err, ErrorTypeDatabase)
 	} else if pizza == nil {
-		return Errorf(ErrorTypeResourceNotFound, "a pizza with the name '%s' does not exist", name)
+		return Errorf(ErrorTypeResourceNotFound, ErrPizzaNotFound, name)
 	}
 
 	if err := c.repository.Delete(pizza.Name); err != nil {
@@ -173,7 +178,7 @@ func (c *controller) Delete(ctx echo.Context) error {
 func checkNameInPath(ctx echo.Context) (string, error) {
 	name := ctx.Param(PathParamName)
 	if name == "" {
-		return "", Error("missing pizza name in path", ErrorTypeBadRequest)
+		return "", Error(ErrParamNameMissing, ErrorTypeBadRequest)
 	}
 	return name, nil
 }

pizza/repository.go

@@ -7,8 +7,8 @@ import (
 
 // errors
 var (
-	ErrPizzaNotFound  = "pizza named %s not found"
-	ErrPizzaNameTaken = "there is already a pizza named %s"
+	ErrPizzaNotFound  = "pizza %s not found"
+	ErrPizzaNameTaken = "pizza '%s' already exists"
 )
 
 // Repository used to persist pizza data.