Propagate non-retryable error messages to client (#5929)

PR #5541 (and issue #5536) enhance error handling, returning body text
as part of the error. However, this is only done for retryable errors;
if non-retryable, error text still does not propagate to clients.

This PR adds handling of non-retryable errors, ensuring any body text is
part of the message returned to the user's code. There is no change to
the circumstances under which errors are reported, just an enhancement
of the content of such an error.

---------

Co-authored-by: Damien Mathieu <42@dmathieu.com>

CHANGELOG.md

@@ -8,6 +8,12 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 
 ## [Unreleased]
 
+### Changed
+
+- Propagate non-retryable error messages to client in `go.opentelemetry.io/otel/exporters/otlp/otlplog/otlploghttp`. (#5929)
+- Propagate non-retryable error messages to client in `go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp`. (#5929)
+- Propagate non-retryable error messages to client in `go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetrichttp`. (#5929)
+
 ### Fixed
 
 - Fix inconsistent request body closing in `go.opentelemetry.io/otel/exporters/otlp/otlplog/otlploghttp`. (#5954)

exporters/otlp/otlplog/otlploghttp/client.go

@@ -157,9 +157,7 @@ func (c *httpClient) uploadLogs(ctx context.Context, data []*logpb.ResourceLogs)
 			}()
 		}
 
-		var rErr error
+		if sc := resp.StatusCode; sc >= 200 && sc <= 299 {
-		switch sc := resp.StatusCode; {
-		case sc >= 200 && sc <= 299:
 			// Success, do not retry.
 
 			// Read the partial success message, if any.
@@ -187,34 +185,34 @@ func (c *httpClient) uploadLogs(ctx context.Context, data []*logpb.ResourceLogs)
 				}
 			}
 			return nil
-		case sc == http.StatusTooManyRequests,
-			sc == http.StatusBadGateway,
-			sc == http.StatusServiceUnavailable,
-			sc == http.StatusGatewayTimeout:
-			// Retry-able failure.
-			rErr = newResponseError(resp.Header, nil)
-
-			// server may return a message with the response
-			// body, so we read it to include in the error
-			// message to be returned. It will help in
-			// debugging the actual issue.
-			var respData bytes.Buffer
-			if _, err := io.Copy(&respData, resp.Body); err != nil {
-				return err
-			}
-
-			// overwrite the error message with the response body
-			// if it is not empty
-			if respStr := strings.TrimSpace(respData.String()); respStr != "" {
-				// Include response for context.
-				e := errors.New(respStr)
-				rErr = newResponseError(resp.Header, e)
-			}
-		default:
-			rErr = fmt.Errorf("failed to send logs to %s: %s", request.URL, resp.Status)
 		}
+		// Error cases.
 
-		return rErr
+		// server may return a message with the response
+		// body, so we read it to include in the error
+		// message to be returned. It will help in
+		// debugging the actual issue.
+		var respData bytes.Buffer
+		if _, err := io.Copy(&respData, resp.Body); err != nil {
+			return err
+		}
+		respStr := strings.TrimSpace(respData.String())
+		if len(respStr) == 0 {
+			respStr = "(empty)"
+		}
+		bodyErr := fmt.Errorf("body: %s", respStr)
+
+		switch resp.StatusCode {
+		case http.StatusTooManyRequests,
+			http.StatusBadGateway,
+			http.StatusServiceUnavailable,
+			http.StatusGatewayTimeout:
+			// Retryable failure.
+			return newResponseError(resp.Header, bodyErr)
+		default:
+			// Non-retryable failure.
+			return fmt.Errorf("failed to send logs to %s: %s (%w)", request.URL, resp.Status, bodyErr)
+		}
 	})
 }
 

exporters/otlp/otlplog/otlploghttp/client_test.go

@@ -778,4 +778,24 @@ func TestConfig(t *testing.T) {
 		require.Contains(t, got, headerKeySetInProxy)
 		assert.Equal(t, []string{headerValueSetInProxy}, got[headerKeySetInProxy])
 	})
+
+	t.Run("non-retryable errors are propagated", func(t *testing.T) {
+		exporterErr := errors.New("missing required attribute aaaa")
+		rCh := make(chan exportResult, 1)
+		rCh <- exportResult{Err: &httpResponseError{
+			Status: http.StatusBadRequest,
+			Err:    exporterErr,
+		}}
+
+		exp, coll := factoryFunc("", rCh, WithRetry(RetryConfig{
+			Enabled: false,
+		}))
+		ctx := context.Background()
+		t.Cleanup(func() { require.NoError(t, coll.Shutdown(ctx)) })
+		// Push this after Shutdown so the HTTP server doesn't hang.
+		t.Cleanup(func() { close(rCh) })
+		t.Cleanup(func() { require.NoError(t, exp.Shutdown(ctx)) })
+		err := exp.Export(ctx, make([]log.Record, 1))
+		assert.ErrorContains(t, err, exporterErr.Error())
+	})
 }

exporters/otlp/otlpmetric/otlpmetrichttp/client.go

@@ -160,9 +160,7 @@ func (c *client) UploadMetrics(ctx context.Context, protoMetrics *metricpb.Resou
 			}()
 		}
 
-		var rErr error
+		if sc := resp.StatusCode; sc >= 200 && sc <= 299 {
-		switch sc := resp.StatusCode; {
-		case sc >= 200 && sc <= 299:
 			// Success, do not retry.
 
 			// Read the partial success message, if any.
@@ -190,34 +188,34 @@ func (c *client) UploadMetrics(ctx context.Context, protoMetrics *metricpb.Resou
 				}
 			}
 			return nil
-		case sc == http.StatusTooManyRequests,
-			sc == http.StatusBadGateway,
-			sc == http.StatusServiceUnavailable,
-			sc == http.StatusGatewayTimeout:
-			// Retry-able failure.
-			rErr = newResponseError(resp.Header, nil)
-
-			// server may return a message with the response
-			// body, so we read it to include in the error
-			// message to be returned. It will help in
-			// debugging the actual issue.
-			var respData bytes.Buffer
-			if _, err := io.Copy(&respData, resp.Body); err != nil {
-				return err
-			}
-
-			// overwrite the error message with the response body
-			// if it is not empty
-			if respStr := strings.TrimSpace(respData.String()); respStr != "" {
-				// Include response for context.
-				e := errors.New(respStr)
-				rErr = newResponseError(resp.Header, e)
-			}
-		default:
-			rErr = fmt.Errorf("failed to send metrics to %s: %s", request.URL, resp.Status)
 		}
+		// Error cases.
 
-		return rErr
+		// server may return a message with the response
+		// body, so we read it to include in the error
+		// message to be returned. It will help in
+		// debugging the actual issue.
+		var respData bytes.Buffer
+		if _, err := io.Copy(&respData, resp.Body); err != nil {
+			return err
+		}
+		respStr := strings.TrimSpace(respData.String())
+		if len(respStr) == 0 {
+			respStr = "(empty)"
+		}
+		bodyErr := fmt.Errorf("body: %s", respStr)
+
+		switch resp.StatusCode {
+		case http.StatusTooManyRequests,
+			http.StatusBadGateway,
+			http.StatusServiceUnavailable,
+			http.StatusGatewayTimeout:
+			// Retryable failure.
+			return newResponseError(resp.Header, bodyErr)
+		default:
+			// Non-retryable failure.
+			return fmt.Errorf("failed to send metrics to %s: %s (%w)", request.URL, resp.Status, bodyErr)
+		}
 	})
 }
 

exporters/otlp/otlpmetric/otlpmetrichttp/client_test.go

@@ -270,4 +270,25 @@ func TestConfig(t *testing.T) {
 		require.Contains(t, got, headerKeySetInProxy)
 		assert.Equal(t, []string{headerValueSetInProxy}, got[headerKeySetInProxy])
 	})
+
+	t.Run("non-retryable errors are propagated", func(t *testing.T) {
+		exporterErr := errors.New("missing required attribute aaa")
+		rCh := make(chan otest.ExportResult, 1)
+		rCh <- otest.ExportResult{Err: &otest.HTTPResponseError{
+			Status: http.StatusBadRequest,
+			Err:    exporterErr,
+		}}
+		exp, coll := factoryFunc("", rCh)
+		ctx := context.Background()
+		t.Cleanup(func() { require.NoError(t, coll.Shutdown(ctx)) })
+		// Push this after Shutdown so the HTTP server doesn't hang.
+		t.Cleanup(func() { close(rCh) })
+		t.Cleanup(func() { require.NoError(t, exp.Shutdown(ctx)) })
+		exCtx, cancel := context.WithTimeout(ctx, time.Second)
+		defer cancel()
+		err := exp.Export(exCtx, &metricdata.ResourceMetrics{})
+		assert.ErrorContains(t, err, exporterErr.Error())
+
+		assert.NoError(t, exCtx.Err())
+	})
 }

exporters/otlp/otlptrace/otlptracehttp/client.go

@@ -166,8 +166,7 @@ func (d *client) UploadTraces(ctx context.Context, protoSpans []*tracepb.Resourc
 			}()
 		}
 
-		switch sc := resp.StatusCode; {
+		if sc := resp.StatusCode; sc >= 200 && sc <= 299 {
-		case sc >= 200 && sc <= 299:
 			// Success, do not retry.
 			// Read the partial success message, if any.
 			var respData bytes.Buffer
@@ -194,33 +193,33 @@ func (d *client) UploadTraces(ctx context.Context, protoSpans []*tracepb.Resourc
 				}
 			}
 			return nil
+		}
+		// Error cases.
 
-		case sc == http.StatusTooManyRequests,
+		// server may return a message with the response
-			sc == http.StatusBadGateway,
+		// body, so we read it to include in the error
-			sc == http.StatusServiceUnavailable,
+		// message to be returned. It will help in
-			sc == http.StatusGatewayTimeout:
+		// debugging the actual issue.
-			// Retry-able failures.
+		var respData bytes.Buffer
-			rErr := newResponseError(resp.Header, nil)
+		if _, err := io.Copy(&respData, resp.Body); err != nil {
+			return err
+		}
+		respStr := strings.TrimSpace(respData.String())
+		if len(respStr) == 0 {
+			respStr = "(empty)"
+		}
+		bodyErr := fmt.Errorf("body: %s", respStr)
 
-			// server may return a message with the response
+		switch resp.StatusCode {
-			// body, so we read it to include in the error
+		case http.StatusTooManyRequests,
-			// message to be returned. It will help in
+			http.StatusBadGateway,
-			// debugging the actual issue.
+			http.StatusServiceUnavailable,
-			var respData bytes.Buffer
+			http.StatusGatewayTimeout:
-			if _, err := io.Copy(&respData, resp.Body); err != nil {
+			// Retryable failure.
-				return err
+			return newResponseError(resp.Header, bodyErr)
-			}
-
-			// overwrite the error message with the response body
-			// if it is not empty
-			if respStr := strings.TrimSpace(respData.String()); respStr != "" {
-				// Include response for context.
-				e := errors.New(respStr)
-				rErr = newResponseError(resp.Header, e)
-			}
-			return rErr
 		default:
-			return fmt.Errorf("failed to send to %s: %s", request.URL, resp.Status)
+			// Non-retryable failure.
+			return fmt.Errorf("failed to send to %s: %s (%w)", request.URL, resp.Status, bodyErr)
 		}
 	})
 }

exporters/otlp/otlptrace/otlptracehttp/client_test.go

@@ -244,6 +244,9 @@ func TestTimeout(t *testing.T) {
 func TestNoRetry(t *testing.T) {
 	mc := runMockCollector(t, mockCollectorConfig{
 		InjectHTTPStatus: []int{http.StatusBadRequest},
+		Partial: &coltracepb.ExportTracePartialSuccess{
+			ErrorMessage: "missing required attribute aaa",
+		},
 	})
 	defer mc.MustStop(t)
 	driver := otlptracehttp.NewClient(
@@ -265,9 +268,14 @@ func TestNoRetry(t *testing.T) {
 	}()
 	err = exporter.ExportSpans(ctx, otlptracetest.SingleReadOnlySpan())
 	assert.Error(t, err)
-	unwrapped := errors.Unwrap(err)
-	assert.Equal(t, fmt.Sprintf("failed to send to http://%s/v1/traces: 400 Bad Request", mc.endpoint), unwrapped.Error())
 	assert.True(t, strings.HasPrefix(err.Error(), "traces export: "))
+
+	unwrapped := errors.Unwrap(err)
+	assert.Contains(t, unwrapped.Error(), fmt.Sprintf("failed to send to http://%s/v1/traces: 400 Bad Request", mc.endpoint))
+
+	unwrapped2 := errors.Unwrap(unwrapped)
+	assert.Contains(t, unwrapped2.Error(), "missing required attribute aaa")
+
 	assert.Empty(t, mc.GetSpans())
 }