Fix otlp exporter error handling misusing backoff.expo

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

@@ -19,13 +19,23 @@
 from collections.abc import Sequence
 from os import environ
 from time import sleep
-from typing import Any, Callable, Dict, Generic, List, Optional, Tuple, Union
+from typing import (
+    Any,
+    Callable,
+    Dict,
+    Generic,
+    List,
+    Optional,
+    Tuple,
+    Union,
+    Iterator,
+)
 from typing import Sequence as TypingSequence
 from typing import TypeVar
 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,
@@ -68,6 +78,12 @@
 }
 
 
+def _expo(*, max_value: int) -> Iterator[int]:
+    gen = backoff.expo()
+    gen.send(None)
+    return gen
+
+
 class InvalidCompressionValueException(Exception):
     def __init__(self, environ_key: str, environ_value: str):
         super().__init__(
@@ -293,11 +309,10 @@ def _export(
         #     delay,
         # )
         max_value = 64
-        # expo returns a generator that yields delay values which grow
+        # _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
 
@@ -311,7 +326,6 @@ def _export(
                 return self._result.SUCCESS
 
             except RpcError as error:
-
                 if error.code() in [
                     StatusCode.CANCELLED,
                     StatusCode.DEADLINE_EXCEEDED,

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

@@ -436,19 +436,19 @@ 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.sleep")
-    def test_unavailable(self, mock_sleep, mock_expo):
-
-        mock_expo.configure_mock(**{"return_value": [1]})
+    def test_unavailable(self, mock_sleep):
 
         add_TraceServiceServicer_to_server(
             TraceServiceServicerUNAVAILABLE(), self.server
         )
         self.assertEqual(
             self.exporter.export([self.span]), SpanExportResult.FAILURE
         )
-        mock_sleep.assert_called_with(1)
+        self.assertEqual(
+            mock_sleep.call_args_list,
+            [((1,),), ((2,),), ((4,),), ((8,),), ((16,),), ((32,),)],
+        )
 
     @patch("opentelemetry.exporter.otlp.proto.grpc.exporter.expo")
     @patch("opentelemetry.exporter.otlp.proto.grpc.exporter.sleep")