add test case for cancelation

Signed-off-by: Sandor Szücs <[email protected]>

io/log_stream_test.go

@@ -3,12 +3,14 @@ package io
 import (
 	"bytes"
 	"context"
+	"errors"
 	"fmt"
 	"io"
 	"net/http"
 	"net/http/httptest"
 	"strings"
 	"testing"
+	"time"
 
 	"github.com/zalando/skipper/filters/flowid"
 )
@@ -135,4 +137,80 @@ func TestHttpBodyLogBody(t *testing.T) {
 		}
 	})
 
+	t.Run("logbody response with canceled request", func(t *testing.T) {
+		sent := strings.Repeat("b", 1024)
+		backend := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			b := make([]byte, 0, 1024)
+			buf := bytes.NewBuffer(b)
+			_, err := io.Copy(buf, r.Body)
+			if err != nil {
+				t.Fatalf("Failed to read body on backend receiver: %v", err)
+			}
+
+			if got := buf.String(); got != sent {
+				t.Fatalf("Failed to get request body in backend. want: %q, got: %q", sent, got)
+			}
+			w.WriteHeader(200)
+			w.(http.Flusher).Flush()
+			time.Sleep(100 * time.Millisecond)
+			w.Write([]byte("OK"))
+		}))
+		defer backend.Close()
+
+		lgbuf := &bytes.Buffer{}
+
+		var b mybuf
+		b.buf = bytes.NewBufferString(sent)
+
+		ctx, cancel := context.WithTimeout(context.Background(), 50*time.Millisecond)
+		defer cancel()
+		req, err := http.NewRequestWithContext(ctx, "POST", backend.URL, b.buf)
+		if err != nil {
+			t.Fatalf("Failed to create request: %v", err)
+		}
+		req.Header.Add(flowid.HeaderName, "qux")
+
+		rsp, err := backend.Client().Do(req)
+		if err != nil {
+			t.Fatalf("Failed to do request, expect no error, but go: %v", err)
+		}
+		if rsp.StatusCode != http.StatusOK {
+			t.Fatalf("Failed to get the expected status code 200, got: %d", rsp.StatusCode)
+		}
+
+		lg := func(format string, args ...interface{}) {
+			s := fmt.Sprintf(format, args...)
+			lgbuf.WriteString(s)
+		}
+		body := LogBody(
+			context.Background(),
+			func(chunk []byte) {
+				lg(
+					`logBody("response") %s: %s`,
+					req.Header.Get(flowid.HeaderName),
+					chunk)
+			},
+			rsp.Body,
+		)
+		defer body.Close()
+		rsp.Body = body
+
+		var buf bytes.Buffer
+		_, err = io.Copy(&buf, rsp.Body)
+		if !errors.Is(err, context.DeadlineExceeded) {
+			t.Fatalf("Failed to get expected error: %v", err)
+		}
+
+		rsp.Body.Close()
+		rspBody := buf.String()
+		if rspBody != "" {
+			t.Fatalf("Failed to get empty response body, got: %q", rspBody)
+		}
+
+		lgData := lgbuf.String()
+		if lgData != "" {
+			t.Fatalf("Failed to get empty log, got: %q", lgData)
+		}
+	})
+
 }