Parse errormsgs in retryable status codes (#5541)

Fixes #5536

---------

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

CHANGELOG.md

@@ -22,6 +22,7 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 - Correct the `Tracer` names used in `go.opentelemetry.io/otel/example/passthrough`. (#5612)
 - Correct the `Meter` name used in `go.opentelemetry.io/otel/example/prometheus`. (#5612)
 - Correct the `Tracer` names used in `go.opentelemetry.io/otel/example/zipkin`. (#5612)
+- Pass the underlying error rather than a generic retry-able failure in `go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetrichttp`, `go.opentelemetry.io/otel/exporters/otlp/otlplog/otlploghttp` and `go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp`. (#5541)
 
 <!-- Released section -->
 <!-- Don't change this section unless doing release -->

exporters/otlp/otlplog/otlploghttp/client.go

@@ -14,6 +14,7 @@ import (
 	"net/http"
 	"net/url"
 	"strconv"
+	"strings"
 	"sync"
 	"time"
 
@@ -143,7 +144,7 @@ func (c *httpClient) uploadLogs(ctx context.Context, data []*logpb.ResourceLogs)
 		resp, err := c.client.Do(request.Request)
 		var urlErr *url.Error
 		if errors.As(err, &urlErr) && urlErr.Temporary() {
-			return newResponseError(http.Header{})
+			return newResponseError(http.Header{}, err)
 		}
 		if err != nil {
 			return err
@@ -184,13 +185,25 @@ func (c *httpClient) uploadLogs(ctx context.Context, data []*logpb.ResourceLogs)
 			sc == http.StatusServiceUnavailable,
 			sc == http.StatusGatewayTimeout:
 			// Retry-able failure.
-			rErr = newResponseError(resp.Header)
+			rErr = newResponseError(resp.Header, nil)
 
-			// Going to retry, drain the body to reuse the connection.
-			if _, err := io.Copy(io.Discard, resp.Body); err != 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 {
 				_ = resp.Body.Close()
 				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)
 		}
@@ -266,24 +279,50 @@ func (r *request) reset(ctx context.Context) {
 // retryableError represents a request failure that can be retried.
 type retryableError struct {
 	throttle int64
+	err      error
 }
 
 // newResponseError returns a retryableError and will extract any explicit
-// throttle delay contained in headers.
-func newResponseError(header http.Header) error {
+// throttle delay contained in headers. The returned error wraps wrapped
+// if it is not nil.
+func newResponseError(header http.Header, wrapped error) error {
 	var rErr retryableError
 	if v := header.Get("Retry-After"); v != "" {
 		if t, err := strconv.ParseInt(v, 10, 64); err == nil {
 			rErr.throttle = t
 		}
 	}
+
+	rErr.err = wrapped
 	return rErr
 }
 
 func (e retryableError) Error() string {
+	if e.err != nil {
+		return fmt.Sprintf("retry-able request failure: %v", e.err.Error())
+	}
+
 	return "retry-able request failure"
 }
 
+func (e retryableError) Unwrap() error {
+	return e.err
+}
+
+func (e retryableError) As(target interface{}) bool {
+	if e.err == nil {
+		return false
+	}
+
+	switch v := target.(type) {
+	case **retryableError:
+		*v = &e
+		return true
+	default:
+		return false
+	}
+}
+
 // evaluate returns if err is retry-able. If it is and it includes an explicit
 // throttling delay, that delay is also returned.
 func evaluate(err error) (bool, time.Duration) {

exporters/otlp/otlplog/otlploghttp/client_test.go

@@ -700,6 +700,30 @@ func TestConfig(t *testing.T) {
 		assert.Len(t, rCh, 0, "failed HTTP responses did not occur")
 	})
 
+	t.Run("WithRetryAndExporterErr", func(t *testing.T) {
+		exporterErr := errors.New("rpc error: code = Unavailable desc = service.name not found in resource attributes")
+		rCh := make(chan exportResult, 1)
+		rCh <- exportResult{Err: &httpResponseError{
+			Status: http.StatusTooManyRequests,
+			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())
+
+		// To test the `Unwrap` and `As` function of retryable error
+		var retryErr *retryableError
+		assert.ErrorAs(t, err, &retryErr)
+		assert.ErrorIs(t, err, *retryErr)
+	})
+
 	t.Run("WithURLPath", func(t *testing.T) {
 		path := "/prefix/v2/logs"
 		ePt := fmt.Sprintf("http://localhost:0%s", path)

exporters/otlp/otlpmetric/otlpmetrichttp/client.go

@@ -14,6 +14,7 @@ import (
 	"net/http"
 	"net/url"
 	"strconv"
+	"strings"
 	"sync"
 	"time"
 
@@ -146,7 +147,7 @@ func (c *client) UploadMetrics(ctx context.Context, protoMetrics *metricpb.Resou
 		resp, err := c.httpClient.Do(request.Request)
 		var urlErr *url.Error
 		if errors.As(err, &urlErr) && urlErr.Temporary() {
-			return newResponseError(http.Header{})
+			return newResponseError(http.Header{}, err)
 		}
 		if err != nil {
 			return err
@@ -187,13 +188,25 @@ func (c *client) UploadMetrics(ctx context.Context, protoMetrics *metricpb.Resou
 			sc == http.StatusServiceUnavailable,
 			sc == http.StatusGatewayTimeout:
 			// Retry-able failure.
-			rErr = newResponseError(resp.Header)
+			rErr = newResponseError(resp.Header, nil)
 
-			// Going to retry, drain the body to reuse the connection.
-			if _, err := io.Copy(io.Discard, resp.Body); err != 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 {
 				_ = resp.Body.Close()
 				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)
 		}
@@ -269,24 +282,50 @@ func (r *request) reset(ctx context.Context) {
 // retryableError represents a request failure that can be retried.
 type retryableError struct {
 	throttle int64
+	err      error
 }
 
 // newResponseError returns a retryableError and will extract any explicit
-// throttle delay contained in headers.
-func newResponseError(header http.Header) error {
+// throttle delay contained in headers. The returned error wraps wrapped
+// if it is not nil.
+func newResponseError(header http.Header, wrapped error) error {
 	var rErr retryableError
 	if v := header.Get("Retry-After"); v != "" {
 		if t, err := strconv.ParseInt(v, 10, 64); err == nil {
 			rErr.throttle = t
 		}
 	}
+
+	rErr.err = wrapped
 	return rErr
 }
 
 func (e retryableError) Error() string {
+	if e.err != nil {
+		return fmt.Sprintf("retry-able request failure: %s", e.err.Error())
+	}
+
 	return "retry-able request failure"
 }
 
+func (e retryableError) Unwrap() error {
+	return e.err
+}
+
+func (e retryableError) As(target interface{}) bool {
+	if e.err == nil {
+		return false
+	}
+
+	switch v := target.(type) {
+	case **retryableError:
+		*v = &e
+		return true
+	default:
+		return false
+	}
+}
+
 // evaluate returns if err is retry-able. If it is and it includes an explicit
 // throttling delay, that delay is also returned.
 func evaluate(err error) (bool, time.Duration) {

exporters/otlp/otlpmetric/otlpmetrichttp/client_test.go

@@ -192,6 +192,30 @@ func TestConfig(t *testing.T) {
 		assert.Len(t, rCh, 0, "failed HTTP responses did not occur")
 	})
 
+	t.Run("WithRetryAndExporterErr", func(t *testing.T) {
+		exporterErr := errors.New("rpc error: code = Unavailable desc = service.name not found in resource attributes")
+		rCh := make(chan otest.ExportResult, 1)
+		rCh <- otest.ExportResult{Err: &otest.HTTPResponseError{
+			Status: http.StatusTooManyRequests,
+			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, &metricdata.ResourceMetrics{})
+		assert.ErrorContains(t, err, exporterErr.Error())
+
+		// To test the `Unwrap` and `As` function of retryable error
+		var retryErr *retryableError
+		assert.ErrorAs(t, err, &retryErr)
+		assert.ErrorIs(t, err, *retryErr)
+	})
+
 	t.Run("WithURLPath", func(t *testing.T) {
 		path := "/prefix/v2/metrics"
 		ePt := fmt.Sprintf("http://localhost:0%s", path)

exporters/otlp/otlptrace/otlptracehttp/client.go

@@ -14,6 +14,7 @@ import (
 	"net/http"
 	"net/url"
 	"strconv"
+	"strings"
 	"sync"
 	"time"
 
@@ -151,7 +152,7 @@ func (d *client) UploadTraces(ctx context.Context, protoSpans []*tracepb.Resourc
 		resp, err := d.client.Do(request.Request)
 		var urlErr *url.Error
 		if errors.As(err, &urlErr) && urlErr.Temporary() {
-			return newResponseError(http.Header{})
+			return newResponseError(http.Header{}, err)
 		}
 		if err != nil {
 			return err
@@ -198,11 +199,27 @@ func (d *client) UploadTraces(ctx context.Context, protoSpans []*tracepb.Resourc
 			sc == http.StatusBadGateway,
 			sc == http.StatusServiceUnavailable,
 			sc == http.StatusGatewayTimeout:
-			// Retry-able failures.  Drain the body to reuse the connection.
-			if _, err := io.Copy(io.Discard, resp.Body); err != nil {
-				otel.Handle(err)
+			// Retry-able failures.
+			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 {
+				_ = resp.Body.Close()
+				return err
 			}
-			return newResponseError(resp.Header)
+
+			// 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)
 		}
@@ -291,24 +308,50 @@ func (r *request) reset(ctx context.Context) {
 // retryableError represents a request failure that can be retried.
 type retryableError struct {
 	throttle int64
+	err      error
 }
 
 // newResponseError returns a retryableError and will extract any explicit
-// throttle delay contained in headers.
-func newResponseError(header http.Header) error {
+// throttle delay contained in headers. The returned error wraps wrapped
+// if it is not nil.
+func newResponseError(header http.Header, wrapped error) error {
 	var rErr retryableError
 	if s, ok := header["Retry-After"]; ok {
 		if t, err := strconv.ParseInt(s[0], 10, 64); err == nil {
 			rErr.throttle = t
 		}
 	}
+
+	rErr.err = wrapped
 	return rErr
 }
 
 func (e retryableError) Error() string {
+	if e.err != nil {
+		return fmt.Sprintf("retry-able request failure: %s", e.err.Error())
+	}
+
 	return "retry-able request failure"
 }
 
+func (e retryableError) Unwrap() error {
+	return e.err
+}
+
+func (e retryableError) As(target interface{}) bool {
+	if e.err == nil {
+		return false
+	}
+
+	switch v := target.(type) {
+	case **retryableError:
+		*v = &e
+		return true
+	default:
+		return false
+	}
+}
+
 // evaluate returns if err is retry-able. If it is and it includes an explicit
 // throttling delay, that delay is also returned.
 func evaluate(err error) (bool, time.Duration) {

exporters/otlp/otlptrace/otlptracehttp/client_test.go

@@ -238,7 +238,7 @@ func TestTimeout(t *testing.T) {
 		assert.NoError(t, exporter.Shutdown(ctx))
 	}()
 	err = exporter.ExportSpans(ctx, otlptracetest.SingleReadOnlySpan())
-	assert.ErrorContains(t, err, "retry-able request failure")
+	assert.ErrorContains(t, err, "context deadline exceeded")
 }
 
 func TestNoRetry(t *testing.T) {