separate commands for the app

Makefile

@@ -9,7 +9,7 @@ all: clean build run
 
 run:
 	@echo "==> Running"
-	@${BIN}
+	@${BIN} run
 
 build: deps fmt
 	@echo "==> Building for prod"

cmd/parser.go

@@ -0,0 +1,10 @@
+package cmd
+
+import "github.com/jessevdk/go-flags"
+
+// Parser will parse command line
+var Parser *flags.Parser
+
+func init() {
+	Parser = flags.NewParser(nil, flags.Default)
+}

cmd/run.go

@@ -0,0 +1,29 @@
+package cmd
+
+import (
+	"fmt"
+	"time"
+
+	"github.com/Neur0toxine/demo-web-service-go/internal"
+	"github.com/brianvoe/gofakeit/v6"
+)
+
+func init() {
+	_, err := Parser.AddCommand("run", "Run the application", "", &RunCommand{})
+	if err != nil {
+		panic(err)
+	}
+}
+
+// RunCommand is used to run the server
+type RunCommand struct{}
+
+func (c *RunCommand) Execute(args []string) error {
+	gofakeit.Seed(time.Now().UnixNano())
+	go internal.ProcessSignals()
+	r := internal.Router()
+	if err := r.Run(":8080"); err != nil {
+		return fmt.Errorf("cannot start the server on :8080 > %w", err)
+	}
+	return nil
+}

go.mod

@@ -5,6 +5,7 @@ go 1.17
 require (
 	github.com/brianvoe/gofakeit/v6 v6.7.1
 	github.com/gin-gonic/gin v1.7.4
+	github.com/jessevdk/go-flags v1.5.0
 	github.com/stretchr/testify v1.7.0
 )
 

go.sum

@@ -26,6 +26,8 @@ github.com/golang/protobuf v1.5.2/go.mod h1:XVQd3VNwM+JqD3oG2Ue2ip4fOMUkwXdXDdiu
 github.com/google/go-cmp v0.5.5 h1:Khx7svrCpmxxtHBq5j2mp/xVjsi8hQMfNLvJFAlrGgU=
 github.com/google/go-cmp v0.5.5/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/google/gofuzz v1.0.0/go.mod h1:dBl0BpW6vV/+mYPU4Po3pmUjxk6FQPldtuIdl/M65Eg=
+github.com/jessevdk/go-flags v1.5.0 h1:1jKYvbxEjfUl0fmqTCOfonvskHHXMjBySTLW4y9LFvc=
+github.com/jessevdk/go-flags v1.5.0/go.mod h1:Fw0T6WPc1dYxT4mKEZRfG5kJhaTDP9pj1c2EWnYs/m4=
 github.com/json-iterator/go v1.1.9/go.mod h1:KdQUCv79m/52Kvf8AW2vK1V8akMuk1QjK/uOdHXbAo4=
 github.com/json-iterator/go v1.1.12 h1:PV8peI4a0ysnczrg+LtxykD8LfKY9ML6u2jnxaEnrnM=
 github.com/json-iterator/go v1.1.12/go.mod h1:e30LSqwooZae/UwlEbR2852Gd8hjQvJoHmT4TnhNGBo=
@@ -77,6 +79,7 @@ golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5h
 golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20200116001909-b77594299b42/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20210320140829-1e4c9ba3b0c4/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20210615035016-665e8c7367d1/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20210630005230-0f9fa26af87c/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20210806184541-e5e7981a1069 h1:siQdpVirKtzPhKl3lZWozZraCFObP8S1v6PRp0bLrtU=

internal/handlers.go

@@ -1,4 +1,4 @@
-package main
+package internal
 
 import (
 	"net/http"
@@ -7,6 +7,7 @@ import (
 	"github.com/gin-gonic/gin"
 )
 
+// AuthorsHandler will return formatted JSOn response with authors
 func AuthorsHandler(c *gin.Context) {
 	c.IndentedJSON(http.StatusOK, repository.Authors())
 }

internal/handlers_test.go

@@ -1,4 +1,4 @@
-package main
+package internal
 
 import (
 	"encoding/json"
@@ -16,7 +16,7 @@ func TestAuthorsHandler(t *testing.T) {
 	req, err := http.NewRequest(http.MethodGet, "/authors", nil)
 	require.NoError(t, err)
 
-	r := router()
+	r := Router()
 	rec := httptest.NewRecorder()
 	r.ServeHTTP(rec, req)
 

internal/router.go

@@ -0,0 +1,12 @@
+package internal
+
+import (
+	"github.com/gin-gonic/gin"
+)
+
+// Router controls the routes
+func Router() (r *gin.Engine) {
+	r = gin.New()
+	r.GET("/authors", AuthorsHandler)
+	return
+}

internal/signals.go

@@ -0,0 +1,22 @@
+package internal
+
+import (
+	"log"
+	"os"
+	"os/signal"
+	"syscall"
+)
+
+// ProcessSignals will react to app termination. It doesn't do much for now, but it can be useful later.
+// For example, we can close active DB or WebSocket connections here, or perform any other actions
+// related to the graceful shutdown.
+func ProcessSignals() {
+	c := make(chan os.Signal, 1)
+	signal.Notify(c, syscall.SIGHUP, syscall.SIGINT, syscall.SIGTERM, syscall.SIGQUIT)
+
+	for {
+		<-c
+		log.Println("Quitting...")
+		os.Exit(0)
+	}
+}

main.go

@@ -1,17 +1,17 @@
 package main
 
 import (
-	"log"
-	"time"
+	"os"
 
-	"github.com/brianvoe/gofakeit/v6"
+	"github.com/Neur0toxine/demo-web-service-go/cmd"
+	"github.com/jessevdk/go-flags"
 )
 
 func main() {
-	gofakeit.Seed(time.Now().UnixNano())
-	go processSignals()
-	r := router()
-	if err := r.Run(":8080"); err != nil {
-		log.Fatalf("cannot start the server on :8080 > %s", err)
+	if _, err := cmd.Parser.Parse(); err != nil {
+		if flagsErr, ok := err.(*flags.Error); ok && flagsErr.Type == flags.ErrHelp {
+			os.Exit(0)
+		}
+		os.Exit(-1)
 	}
 }

router.go

@@ -1,9 +0,0 @@
-package main
-
-import "github.com/gin-gonic/gin"
-
-func router() (r *gin.Engine) {
-	r = gin.New()
-	r.GET("/authors", AuthorsHandler)
-	return
-}

signals.go

@@ -1,19 +0,0 @@
-package main
-
-import (
-	"log"
-	"os"
-	"os/signal"
-	"syscall"
-)
-
-func processSignals() {
-	c := make(chan os.Signal, 1)
-	signal.Notify(c, syscall.SIGHUP, syscall.SIGINT, syscall.SIGTERM, syscall.SIGQUIT)
-
-	for {
-		<-c
-		log.Println("Quitting...")
-		os.Exit(0)
-	}
-}