set span error when http status code >= 400 on client side

plugins/http/client_intercepter.go

@@ -51,6 +51,9 @@ func (h *ClientInterceptor) AfterInvoke(invocation operator.Invocation, result .
 	span := invocation.GetContext().(tracing.Span)
 	if resp, ok := result[0].(*http.Response); ok && resp != nil {
 		span.Tag(tracing.TagStatusCode, fmt.Sprintf("%d", resp.StatusCode))
+		if resp.StatusCode >= 400 {
+			span.ErrorOccured()
+		}
 	}
 	if err, ok := result[1].(error); ok && err != nil {
 		span.Error(err.Error())

plugins/http/client_intercepter_test.go

@@ -57,3 +57,27 @@ func TestClientInvoke(t *testing.T) {
 	assert.Nil(t, spans[0].Refs(), "refs should be nil")
 	assert.Greater(t, spans[0].EndTime(), spans[0].StartTime(), "end time should be greater than start time")
 }
+
+func TestClientInvokeError(t *testing.T) {
+	defer core.ResetTracingContext()
+	interceptor := &ClientInterceptor{}
+	request, err := http.NewRequest("GET", "http://localhost/", http.NoBody)
+	assert.Nil(t, err, "new request error should be nil")
+	invocation := operator.NewInvocation(nil, request)
+	err = interceptor.BeforeInvoke(invocation)
+	assert.Nil(t, err, "before invoke error should be nil")
+	assert.NotNil(t, invocation.GetContext(), "context should not be nil")
+
+	time.Sleep(100 * time.Millisecond)
+
+	err = interceptor.AfterInvoke(invocation, &http.Response{
+		StatusCode: 500,
+	}, nil)
+	assert.Nil(t, err, "after invoke error should be nil")
+
+	time.Sleep(100 * time.Millisecond)
+	spans := core.GetReportedSpans()
+	assert.NotNil(t, spans, "spans should not be nil")
+	assert.Equal(t, 1, len(spans), "spans length should be 1")
+	assert.True(t, spans[0].IsError(), "span should be error")
+}