reorganization of _examples and add some new examples such as iris+groupcache+mysql+docker

Former-commit-id: ed635ee95de7160cde11eaabc0c1dcb0e460a620

_examples/database/mongodb/main.go

@@ -0,0 +1,83 @@
+package main
+
+// go get -u go.mongodb.org/mongo-driver
+// go get -u github.com/joho/godotenv
+
+import (
+	"context"
+	"flag"
+	"fmt"
+	"log"
+	"os"
+
+	// APIs
+	storeapi "myapp/api/store"
+
+	//
+	"myapp/env"
+	"myapp/store"
+
+	"github.com/kataras/iris/v12"
+
+	"go.mongodb.org/mongo-driver/mongo"
+	"go.mongodb.org/mongo-driver/mongo/options"
+)
+
+const version = "0.0.1"
+
+func init() {
+	envFileName := ".env"
+
+	flagset := flag.CommandLine
+	flagset.StringVar(&envFileName, "env", envFileName, "the env file which web app will use to extract its environment variables")
+	flagset.Parse(os.Args[1:])
+
+	env.Load(envFileName)
+}
+
+func main() {
+	clientOptions := options.Client().SetHosts([]string{env.DSN})
+	client, err := mongo.Connect(context.Background(), clientOptions)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	err = client.Ping(context.Background(), nil)
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer client.Disconnect(context.TODO())
+
+	db := client.Database("store")
+
+	var (
+		// Collections.
+		moviesCollection = db.Collection("movies")
+
+		// Services.
+		movieService = store.NewMovieService(moviesCollection)
+	)
+
+	app := iris.New()
+	app.Use(func(ctx iris.Context) {
+		ctx.Header("Server", "Iris MongoDB/"+version)
+		ctx.Next()
+	})
+
+	storeAPI := app.Party("/api/store")
+	{
+		movieHandler := storeapi.NewMovieHandler(movieService)
+		storeAPI.Get("/movies", movieHandler.GetAll)
+		storeAPI.Post("/movies", movieHandler.Add)
+		storeAPI.Get("/movies/{id}", movieHandler.Get)
+		storeAPI.Put("/movies/{id}", movieHandler.Update)
+		storeAPI.Delete("/movies/{id}", movieHandler.Delete)
+	}
+
+	// GET: http://localhost:8080/api/store/movies
+	// POST: http://localhost:8080/api/store/movies
+	// GET: http://localhost:8080/api/store/movies/{id}
+	// PUT: http://localhost:8080/api/store/movies/{id}
+	// DELETE: http://localhost:8080/api/store/movies/{id}
+	app.Listen(fmt.Sprintf(":%s", env.Port), iris.WithOptimizations)
+}