From 593ccaa0cdfd7dee1fde6967a36de3c0cf210f62 Mon Sep 17 00:00:00 2001
From: Stefan Prodan <stefan.prodan@gmail.com>
Date: Tue, 21 Aug 2018 03:12:20 +0300
Subject: [PATCH] Add random delay and errors middleware

---
 cmd/podinfo/main.go |  2 ++
 pkg/api/echo.go     |  4 ++--
 pkg/api/http.go     | 27 +++++++++++++++++++++++++++
 pkg/api/server.go   |  8 ++++++++
 4 files changed, 39 insertions(+), 2 deletions(-)

diff --git a/cmd/podinfo/main.go b/cmd/podinfo/main.go
index 645538e..791976a 100644
--- a/cmd/podinfo/main.go
+++ b/cmd/podinfo/main.go
@@ -32,6 +32,8 @@ func main() {
 	fs.String("ui-path", "./ui", "UI local path")
 	fs.String("ui-color", "blue", "UI color")
 	fs.String("ui-message", fmt.Sprintf("greetings from podinfo v%v", version.VERSION), "UI message")
+	fs.Bool("random-delay", false, "between 0 and 5 seconds random delay")
+	fs.Bool("random-error", false, "1/3 chances of a random response error")
 	fs.Int("stress-cpu", 0, "Number of CPU cores with 100 load")
 	fs.Int("stress-memory", 0, "MB of data to load into memory")
 	versionFlag := fs.Bool("version", false, "get version number")
diff --git a/pkg/api/echo.go b/pkg/api/echo.go
index 25ed7e5..80fde02 100644
--- a/pkg/api/echo.go
+++ b/pkg/api/echo.go
@@ -5,6 +5,7 @@ import (
 	"context"
 	"io/ioutil"
 	"net/http"
+
 	"github.com/stefanprodan/k8s-podinfo/pkg/version"
 	"go.uber.org/zap"
 )
@@ -16,6 +17,7 @@ func (s *Server) echoHandler(w http.ResponseWriter, r *http.Request) {
 		s.ErrorResponse(w, r, "invalid request body", http.StatusBadRequest)
 		return
 	}
+	defer r.Body.Close()
 
 	if len(s.config.BackendURL) > 0 {
 		backendReq, err := http.NewRequest("POST", s.config.BackendURL, bytes.NewReader(body))
@@ -75,5 +77,3 @@ func (s *Server) echoHandler(w http.ResponseWriter, r *http.Request) {
 		w.Write(body)
 	}
 }
-
-
diff --git a/pkg/api/http.go b/pkg/api/http.go
index 2db9262..1906a22 100644
--- a/pkg/api/http.go
+++ b/pkg/api/http.go
@@ -5,10 +5,37 @@ import (
 	"encoding/json"
 	"net/http"
 
+	"math/rand"
+	"time"
+
 	"github.com/stefanprodan/k8s-podinfo/pkg/version"
 	"go.uber.org/zap"
 )
 
+func randomDelayMiddleware(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		min := 0
+		max := 5
+		rand.Seed(time.Now().Unix())
+		delay := rand.Intn(max-min) + min
+		time.Sleep(time.Duration(delay) * time.Second)
+		next.ServeHTTP(w, r)
+	})
+}
+
+func randomErrorMiddleware(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		rand.Seed(time.Now().Unix())
+		if rand.Int31n(3) == 0 {
+
+			errors := []int{http.StatusInternalServerError, http.StatusBadRequest, http.StatusConflict}
+			w.WriteHeader(errors[rand.Intn(len(errors))])
+			return
+		}
+		next.ServeHTTP(w, r)
+	})
+}
+
 func versionMiddleware(next http.Handler) http.Handler {
 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		r.Header.Set("X-API-Version", version.VERSION)
diff --git a/pkg/api/server.go b/pkg/api/server.go
index 6d5e06c..8a47333 100644
--- a/pkg/api/server.go
+++ b/pkg/api/server.go
@@ -34,6 +34,8 @@ type Config struct {
 	ConfigPath                string        `mapstructure:"config-path"`
 	Port                      string        `mapstructure:"port"`
 	Hostname                  string        `mapstructure:"hostname"`
+	RandomDelay               bool          `mapstructure:"random-delay"`
+	RandomError               bool          `mapstructure:"random-error"`
 }
 
 type Server struct {
@@ -80,6 +82,12 @@ func (s *Server) registerMiddlewares() {
 	httpLogger := NewLoggingMiddleware(s.logger)
 	s.router.Use(httpLogger.Handler)
 	s.router.Use(versionMiddleware)
+	if s.config.RandomDelay {
+		s.router.Use(randomDelayMiddleware)
+	}
+	if s.config.RandomError {
+		s.router.Use(randomErrorMiddleware)
+	}
 }
 
 func (s *Server) ListenAndServe(stopCh <-chan struct{}) {