k6runner: use check context for http request (#715)

internal/k6runner/k6runner.go

@@ -337,17 +337,32 @@ func (r HttpRunner) WithLogger(logger *zerolog.Logger) Runner {
 var ErrUnexpectedStatus = errors.New("unexpected status code")
 
 func (r HttpRunner) Run(ctx context.Context, script []byte) (*RunResponse, error) {
-	req, err := json.Marshal(&RunRequest{
+	k6Timeout := getTimeout(ctx)
+
+	reqBody, err := json.Marshal(&RunRequest{
 		Script: script,
 		Settings: Settings{
-			Timeout: getTimeout(ctx).Milliseconds(),
+			Timeout: k6Timeout.Milliseconds(),
 		},
 	})
 	if err != nil {
 		return nil, fmt.Errorf("running script: %w", err)
 	}
 
-	resp, err := http.Post(r.url, "application/json", bytes.NewBuffer(req))
+	// The context above carries the check timeout, which will be eventually passed to k6 by the runner at the other end
+	// of this request. To account for network overhead, we create a different context with an extra second of timeout,
+	// which adds some grace time to account for the network/system latency of the http request.
+	reqCtx, cancel := context.WithTimeout(context.Background(), k6Timeout+time.Second)
+	defer cancel()
+
+	req, err := http.NewRequestWithContext(reqCtx, http.MethodPost, r.url, bytes.NewReader(reqBody))
+	if err != nil {
+		return nil, fmt.Errorf("building request: %w", err)
+	}
+
+	req.Header.Add("content-type", "application/json")
+
+	resp, err := http.DefaultClient.Do(req)
 	if err != nil {
 		r.logger.Error().Err(err).Msg("sending request")
 		return nil, fmt.Errorf("running script: %w", err)

internal/k6runner/k6runner_test.go

@@ -177,6 +177,7 @@ func TestScriptHTTPRun(t *testing.T) {
 	for _, tc := range []struct {
 		name          string
 		response      *RunResponse
+		delay         time.Duration
 		statusCode    int
 		expectSuccess bool
 		expectError   error
@@ -249,6 +250,17 @@ func TestScriptHTTPRun(t *testing.T) {
 			expectSuccess: false,
 			expectError:   ErrBuggyRunner,
 		},
+		{
+			name: "request timeout",
+			response: &RunResponse{
+				Metrics: testMetrics,
+				Logs:    testLogs,
+			},
+			delay:         2 * time.Second,
+			statusCode:    http.StatusInternalServerError,
+			expectSuccess: false,
+			expectError:   context.DeadlineExceeded,
+		},
 	} {
 		tc := tc
 
@@ -257,6 +269,7 @@ func TestScriptHTTPRun(t *testing.T) {
 
 			mux := http.NewServeMux()
 			mux.HandleFunc("/run", func(w http.ResponseWriter, r *http.Request) {
+				time.Sleep(tc.delay)
 				w.Header().Set("Content-Type", "application/json")
 				w.WriteHeader(tc.statusCode)
 				_ = json.NewEncoder(w).Encode(tc.response)
@@ -268,7 +281,9 @@ func TestScriptHTTPRun(t *testing.T) {
 			script, err := NewScript([]byte("tee-hee"), runner)
 			require.NoError(t, err)
 
-			ctx, cancel := testhelper.Context(context.Background(), t)
+			baseCtx, baseCancel := context.WithTimeout(context.Background(), time.Second)
+			t.Cleanup(baseCancel)
+			ctx, cancel := testhelper.Context(baseCtx, t)
 			t.Cleanup(cancel)
 
 			var (