Detect and adapt to backoff package version

Since backoff==2.0.0, the API of the expo function has changed. The
"porcelain" methods of the backoff library (the decorators
backoff.on_exception and backoff.on_predicate) send a "None" value into
the generator and discard the first yielded value. This is for
compatibility with the more general wait generator API inside the
backoff package.

This commit allows the OTLP exporters to automatically detect the
behavior of the installed backoff package and adapt accordingly.

Author: nickstenning

CHANGELOG.md

@@ -13,6 +13,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   ([#2959](https://github.com/open-telemetry/opentelemetry-python/pull/2959))
 - Add http-metric instrument names to semantic conventions
   ([#2976](https://github.com/open-telemetry/opentelemetry-python/pull/2976))
+- Fix a bug with exporter retries for with newer versions of the backoff library
+  ([#2980](https://github.com/open-telemetry/opentelemetry-python/pull/2980))
 
 ## [1.13.0-0.34b0](https://github.com/open-telemetry/opentelemetry-python/releases/tag/v1.13.0) - 2022-09-26
 

exporter/opentelemetry-exporter-otlp-proto-grpc/src/opentelemetry/exporter/otlp/proto/grpc/exporter.py

@@ -25,7 +25,7 @@
 from urllib.parse import urlparse
 from opentelemetry.sdk.trace import ReadableSpan
 
-from backoff import expo
+import backoff
 from google.rpc.error_details_pb2 import RetryInfo
 from grpc import (
     ChannelCredentials,
@@ -183,6 +183,20 @@ def _get_credentials(creds, environ_key):
     return ssl_channel_credentials()
 
 
+# Work around API change between backoff 1.x and 2.x. Since 2.0.0 the backoff
+# wait generator API requires a first .send(None) before reading the backoff
+# values from the generator.
+if next(backoff.expo()) is None:
+
+    def _expo(*args, **kwargs):
+        gen = backoff.expo(*args, **kwargs)
+        gen.send(None)
+        return gen
+
+else:
+    _expo = backoff.expo
+
+
 # pylint: disable=no-member
 class OTLPExporterMixin(
     ABC, Generic[SDKDataT, ExportServiceRequestT, ExportResultT]
@@ -296,7 +310,7 @@ def _export(
         # expo returns a generator that yields delay values which grow
         # exponentially. Once delay is greater than max_value, the yielded
         # value will remain constant.
-        for delay in expo(max_value=max_value):
+        for delay in _expo(max_value=max_value):
 
             if delay == max_value:
                 return self._result.FAILURE

exporter/opentelemetry-exporter-otlp-proto-grpc/tests/logs/test_otlp_logs_exporter.py

@@ -251,7 +251,7 @@ def test_otlp_exporter_endpoint(self, mock_secure, mock_insecure):
             )
             mock_method.reset_mock()
 
-    @patch("opentelemetry.exporter.otlp.proto.grpc.exporter.expo")
+    @patch("opentelemetry.exporter.otlp.proto.grpc.exporter._expo")
     @patch("opentelemetry.exporter.otlp.proto.grpc.exporter.sleep")
     def test_unavailable(self, mock_sleep, mock_expo):
 
@@ -265,7 +265,7 @@ def test_unavailable(self, mock_sleep, mock_expo):
         )
         mock_sleep.assert_called_with(1)
 
-    @patch("opentelemetry.exporter.otlp.proto.grpc.exporter.expo")
+    @patch("opentelemetry.exporter.otlp.proto.grpc.exporter._expo")
     @patch("opentelemetry.exporter.otlp.proto.grpc.exporter.sleep")
     def test_unavailable_delay(self, mock_sleep, mock_expo):
 

exporter/opentelemetry-exporter-otlp-proto-grpc/tests/metrics/test_otlp_metrics_exporter.py

@@ -449,7 +449,7 @@ def test_otlp_exporter_endpoint(self, mock_secure, mock_insecure):
             )
             mock_method.reset_mock()
 
-    @patch("opentelemetry.exporter.otlp.proto.grpc.exporter.expo")
+    @patch("opentelemetry.exporter.otlp.proto.grpc.exporter._expo")
     @patch("opentelemetry.exporter.otlp.proto.grpc.exporter.sleep")
     def test_unavailable(self, mock_sleep, mock_expo):
 
@@ -464,7 +464,7 @@ def test_unavailable(self, mock_sleep, mock_expo):
         )
         mock_sleep.assert_called_with(1)
 
-    @patch("opentelemetry.exporter.otlp.proto.grpc.exporter.expo")
+    @patch("opentelemetry.exporter.otlp.proto.grpc.exporter._expo")
     @patch("opentelemetry.exporter.otlp.proto.grpc.exporter.sleep")
     def test_unavailable_delay(self, mock_sleep, mock_expo):
 

exporter/opentelemetry-exporter-otlp-proto-grpc/tests/test_otlp_exporter_mixin.py

@@ -56,7 +56,7 @@ def test_environ_to_compression(self):
             with self.assertRaises(InvalidCompressionValueException):
                 environ_to_compression("test_invalid")
 
-    @patch("opentelemetry.exporter.otlp.proto.grpc.exporter.expo")
+    @patch("opentelemetry.exporter.otlp.proto.grpc.exporter._expo")
     def test_export_warning(self, mock_expo):
 
         mock_expo.configure_mock(**{"return_value": [0]})

exporter/opentelemetry-exporter-otlp-proto-grpc/tests/test_otlp_trace_exporter.py

@@ -436,7 +436,7 @@ def test_otlp_headers(self, mock_ssl_channel, mock_secure):
         # pylint: disable=protected-access
         self.assertIsNone(exporter._headers, None)
 
-    @patch("opentelemetry.exporter.otlp.proto.grpc.exporter.expo")
+    @patch("opentelemetry.exporter.otlp.proto.grpc.exporter._expo")
     @patch("opentelemetry.exporter.otlp.proto.grpc.exporter.sleep")
     def test_unavailable(self, mock_sleep, mock_expo):
 
@@ -450,7 +450,7 @@ def test_unavailable(self, mock_sleep, mock_expo):
         )
         mock_sleep.assert_called_with(1)
 
-    @patch("opentelemetry.exporter.otlp.proto.grpc.exporter.expo")
+    @patch("opentelemetry.exporter.otlp.proto.grpc.exporter._expo")
     @patch("opentelemetry.exporter.otlp.proto.grpc.exporter.sleep")
     def test_unavailable_delay(self, mock_sleep, mock_expo):
 

exporter/opentelemetry-exporter-otlp-proto-http/src/opentelemetry/exporter/otlp/proto/http/_log_exporter/__init__.py

@@ -20,8 +20,8 @@
 from typing import Dict, Optional, Sequence
 from time import sleep
 
+import backoff
 import requests
-from backoff import expo
 
 from opentelemetry.sdk.environment_variables import (
     OTEL_EXPORTER_OTLP_CERTIFICATE,
@@ -53,6 +53,19 @@
 DEFAULT_LOGS_EXPORT_PATH = "v1/logs"
 DEFAULT_TIMEOUT = 10  # in seconds
 
+# Work around API change between backoff 1.x and 2.x. Since 2.0.0 the backoff
+# wait generator API requires a first .send(None) before reading the backoff
+# values from the generator.
+if next(backoff.expo()) is None:
+
+    def _expo(*args, **kwargs):
+        gen = backoff.expo(*args, **kwargs)
+        gen.send(None)
+        return gen
+
+else:
+    _expo = backoff.expo
+
 
 class OTLPLogExporter(LogExporter):
 
@@ -122,7 +135,7 @@ def export(self, batch: Sequence[LogData]) -> LogExportResult:
 
         serialized_data = _ProtobufEncoder.serialize(batch)
 
-        for delay in expo(max_value=self._MAX_RETRY_TIMEOUT):
+        for delay in _expo(max_value=self._MAX_RETRY_TIMEOUT):
 
             if delay == self._MAX_RETRY_TIMEOUT:
                 return LogExportResult.FAILURE

exporter/opentelemetry-exporter-otlp-proto-http/src/opentelemetry/exporter/otlp/proto/http/trace_exporter/__init__.py

@@ -20,8 +20,8 @@
 from typing import Dict, Optional
 from time import sleep
 
+import backoff
 import requests
-from backoff import expo
 
 from opentelemetry.sdk.environment_variables import (
     OTEL_EXPORTER_OTLP_TRACES_CERTIFICATE,
@@ -54,6 +54,19 @@
 DEFAULT_TRACES_EXPORT_PATH = "v1/traces"
 DEFAULT_TIMEOUT = 10  # in seconds
 
+# Work around API change between backoff 1.x and 2.x. Since 2.0.0 the backoff
+# wait generator API requires a first .send(None) before reading the backoff
+# values from the generator.
+if next(backoff.expo()) is None:
+
+    def _expo(*args, **kwargs):
+        gen = backoff.expo(*args, **kwargs)
+        gen.send(None)
+        return gen
+
+else:
+    _expo = backoff.expo
+
 
 class OTLPSpanExporter(SpanExporter):
 
@@ -133,7 +146,7 @@ def export(self, spans) -> SpanExportResult:
 
         serialized_data = _ProtobufEncoder.serialize(spans)
 
-        for delay in expo(max_value=self._MAX_RETRY_TIMEOUT):
+        for delay in _expo(max_value=self._MAX_RETRY_TIMEOUT):
 
             if delay == self._MAX_RETRY_TIMEOUT:
                 return SpanExportResult.FAILURE