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

Former-commit-id: ed635ee95de7160cde11eaabc0c1dcb0e460a620

_examples/logging/request-logger/request-logger-file-json/main.go

@@ -0,0 +1,110 @@
+package main
+
+import (
+	"fmt"
+	"io"
+	"os"
+	"strings"
+	"time"
+
+	"github.com/kataras/iris/v12"
+	"github.com/kataras/iris/v12/middleware/logger"
+)
+
+const deleteFileOnExit = false
+
+func newRequestLogger(newWriter io.Writer) iris.Handler {
+	c := logger.Config{}
+	c.AddSkipper(func(ctx iris.Context) bool {
+		path := ctx.Path()
+		for _, ext := range excludeExtensions {
+			if strings.HasSuffix(path, ext) {
+				return true
+			}
+		}
+		return false
+	})
+
+	c.LogFuncCtx = func(ctx iris.Context, latency time.Duration) {
+		datetime := time.Now().Format(ctx.Application().ConfigurationReadOnly().GetTimeFormat())
+		customHandlerMessage := ctx.Values().GetString("log_message")
+
+		file, line := ctx.HandlerFileLine()
+		source := fmt.Sprintf("%s:%d", file, line)
+
+		// this will just append a line without an array of javascript objects, readers of this file should read one line per log javascript object,
+		// however, you can improve it even more, this is just a simple example on how to use the `LogFuncCtx`.
+		jsonStr := fmt.Sprintf(`{"datetime":"%s","level":"%s","source":"%s","latency": "%s","status": %d,"method":"%s","path":"%s","message":"%s"}`,
+			datetime, "INFO", source, latency.String(), ctx.GetStatusCode(), ctx.Method(), ctx.Path(), customHandlerMessage)
+
+		fmt.Fprintln(newWriter, jsonStr)
+	}
+
+	return logger.New(c)
+}
+
+func h(ctx iris.Context) {
+	ctx.Values().Set("log_message", "something to give more info to the request logger")
+
+	ctx.Writef("Hello from %s", ctx.Path())
+}
+
+func main() {
+	app := iris.New()
+
+	logFile := newLogFile()
+	defer func() {
+		logFile.Close()
+		if deleteFileOnExit {
+			os.Remove(logFile.Name())
+		}
+	}()
+
+	r := newRequestLogger(logFile)
+
+	app.Use(r)
+	app.OnAnyErrorCode(r, func(ctx iris.Context) {
+		ctx.HTML("<h1> Error: Please try <a href ='/'> this </a> instead.</h1>")
+	})
+
+	app.Get("/", h)
+
+	app.Get("/1", h)
+
+	app.Get("/2", h)
+
+	app.Get("/", h)
+
+	// http://localhost:8080
+	// http://localhost:8080/1
+	// http://localhost:8080/2
+	// http://lcoalhost:8080/notfoundhere
+	app.Listen(":8080")
+}
+
+var excludeExtensions = [...]string{
+	".js",
+	".css",
+	".jpg",
+	".png",
+	".ico",
+	".svg",
+}
+
+// get a filename based on the date, file logs works that way the most times
+// but these are just a sugar.
+func todayFilename() string {
+	today := time.Now().Format("Jan 02 2006")
+	return today + ".json"
+}
+
+func newLogFile() *os.File {
+	filename := todayFilename()
+	// open an output file, this will append to the today's file if server restarted.
+	f, err := os.OpenFile(filename, os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0666)
+	if err != nil {
+		panic(err)
+	}
+
+	return f
+}