Artificial delay for testing

config/config.go

@@ -19,6 +19,7 @@ type Config struct {
 	MaxFileSize  int64
 	RPS          int
 	SysRPS       int
+	Delay        time.Duration
 }
 
 func New() Config {
@@ -38,6 +39,7 @@ func New() Config {
 	as.Append(args.STRING, "drivertype", "database driver to use", "boltdb")
 	as.Append(args.BOOL, "auth", "check for authorized access", false)
 	as.Append(args.DURATION, "authlifetime", "duration auth is valid for", time.Hour)
+	as.Append(args.DURATION, "delay", "time to delay requests", time.Duration(0))
 	as.Append(args.INT, "max-file-size", "max file size for uploads in bytes", 50*(1<<20))
 	as.Append(args.INT, "rps", "rps per namespace", 5)
 	as.Append(args.INT, "sys-rps", "rps for the sys", 10)
@@ -56,6 +58,7 @@ func New() Config {
 		DriverType:   as.GetString("drivertype"),
 		Auth:         as.GetBool("auth"),
 		AuthLifetime: as.GetDuration("authlifetime"),
+		Delay:        as.GetDuration("delay"),
 		MaxFileSize:  int64(as.GetInt("max-file-size")),
 		RPS:          as.GetInt("rps"),
 		SysRPS:       as.GetInt("sys-rps"),

view/json.go

@@ -11,6 +11,7 @@ import (
 	"log"
 	"net/http"
 	"strings"
+	"time"
 
 	"golang.org/x/time/rate"
 )
@@ -60,6 +61,10 @@ func jsonHandler(g storage.RateLimitedGraph) http.Handler {
 		foo := route.foo
 		auth := !route.noauth
 		mux.HandleFunc(route.path, func(w http.ResponseWriter, r *http.Request) {
+			if err := delay(w, r); err != nil {
+				http.Error(w, err.Error(), 499)
+			}
+
 			if auth {
 				if err := Auth(g, w, r); err != nil {
 					return
@@ -134,3 +139,12 @@ func version(_ storage.RateLimitedGraph, w http.ResponseWriter, _ *http.Request)
 	enc.SetIndent("", "   ")
 	return enc.Encode(map[string]string{"version": GitCommit})
 }
+
+func delay(w http.ResponseWriter, r *http.Request) error {
+	select {
+	case <-time.After(config.New().Delay):
+	case <-r.Context().Done():
+		return errors.New("client DCd")
+	}
+	return nil
+}

view/json_test.go

@@ -125,3 +125,35 @@ func TestVersion(t *testing.T) {
 		}
 	})
 }
+
+func TestDelay(t *testing.T) {
+	defer func() {
+		os.Setenv("DELAY", "0ms")
+	}()
+	os.Args = os.Args[:1]
+	os.Setenv("DELAY", "100ms")
+
+	r := httptest.NewRequest("GET", "/", nil)
+	w := httptest.NewRecorder()
+
+	start := time.Now()
+	if err := delay(w, r); err != nil {
+		t.Fatal(err)
+	}
+	if since := time.Since(start); since < time.Millisecond*100 {
+		t.Fatal(since)
+	}
+
+	r = httptest.NewRequest("GET", "/", nil)
+	ctx, can := context.WithCancel(r.Context())
+	can()
+	r = r.WithContext(ctx)
+	w = httptest.NewRecorder()
+	start = time.Now()
+	if err := delay(w, r); err == nil {
+		t.Fatal(err)
+	}
+	if since := time.Since(start); since > time.Millisecond*99 {
+		t.Fatal(since)
+	}
+}