Flush meter provider at end of lambda function handler (#1613)

* Flush meter provider at end of lambda function handler

Signed-off-by: Anthony J Mirabella <a9@aneurysm9.com>

* Update `force_flush()` check based on PR feedback

Signed-off-by: Anthony J Mirabella <a9@aneurysm9.com>

---------

Signed-off-by: Anthony J Mirabella <a9@aneurysm9.com>

CHANGELOG.md

@@ -13,6 +13,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   ([#1553](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/1553))
 - `opentelemetry/sdk/extension/aws` Implement [`aws.ecs.*`](https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/resource/semantic_conventions/cloud_provider/aws/ecs.md) and [`aws.logs.*`](https://opentelemetry.io/docs/reference/specification/resource/semantic_conventions/cloud_provider/aws/logs/) resource attributes in the `AwsEcsResourceDetector` detector when the ECS Metadata v4 is available
   ([#1212](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/1212))
+- `opentelemetry-instrumentation-aws-lambda` Flush `MeterProvider` at end of function invocation.
+  ([#1613](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/1613))
 - Fix aiohttp bug with unset `trace_configs` ([#1592](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/1592))
 
 ### Fixed

instrumentation/opentelemetry-instrumentation-aws-lambda/src/opentelemetry/instrumentation/aws_lambda/__init__.py

@@ -45,6 +45,7 @@ def lambda_handler(event, context):
 The `instrument` method accepts the following keyword args:
 
 tracer_provider (TracerProvider) - an optional tracer provider
+meter_provider (MeterProvider) - an optional meter provider
 event_context_extractor (Callable) - a function that returns an OTel Trace
 Context given the Lambda Event the AWS Lambda was invoked with
 this function signature is: def event_context_extractor(lambda_event: Any) -> Context
@@ -68,6 +69,7 @@ def custom_event_context_extractor(lambda_event):
 
 import logging
 import os
+import time
 from importlib import import_module
 from typing import Any, Callable, Collection
 from urllib.parse import urlencode
@@ -79,6 +81,10 @@ def custom_event_context_extractor(lambda_event):
 from opentelemetry.instrumentation.aws_lambda.version import __version__
 from opentelemetry.instrumentation.instrumentor import BaseInstrumentor
 from opentelemetry.instrumentation.utils import unwrap
+from opentelemetry.metrics import (
+    MeterProvider,
+    get_meter_provider,
+)
 from opentelemetry.propagate import get_global_textmap
 from opentelemetry.propagators.aws.aws_xray_propagator import (
     TRACE_HEADER_KEY,
@@ -274,6 +280,7 @@ def _instrument(
     event_context_extractor: Callable[[Any], Context],
     tracer_provider: TracerProvider = None,
     disable_aws_context_propagation: bool = False,
+    meter_provider: MeterProvider = None,
 ):
     def _instrumented_lambda_handler_call(
         call_wrapped, instance, args, kwargs
@@ -352,15 +359,33 @@ def _instrumented_lambda_handler_call(
                         result.get("statusCode"),
                     )
 
+        now = time.time()
         _tracer_provider = tracer_provider or get_tracer_provider()
-        try:
-            # NOTE: `force_flush` before function quit in case of Lambda freeze.
-            # Assumes we are using the OpenTelemetry SDK implementation of the
-            # `TracerProvider`.
-            _tracer_provider.force_flush(flush_timeout)
-        except Exception:  # pylint: disable=broad-except
-            logger.error(
-                "TracerProvider was missing `force_flush` method. This is necessary in case of a Lambda freeze and would exist in the OTel SDK implementation."
+        if hasattr(_tracer_provider, "force_flush"):
+            try:
+                # NOTE: `force_flush` before function quit in case of Lambda freeze.
+                _tracer_provider.force_flush(flush_timeout)
+            except Exception:  # pylint: disable=broad-except
+                logger.exception(
+                    f"TracerProvider failed to flush traces"
+                )
+        else:
+            logger.warning("TracerProvider was missing `force_flush` method. This is necessary in case of a Lambda freeze and would exist in the OTel SDK implementation.")
+
+        _meter_provider = meter_provider or get_meter_provider()
+        if hasattr(_meter_provider, "force_flush"):
+            rem = flush_timeout - (time.time()-now)*1000
+            if rem > 0:
+                try:
+                    # NOTE: `force_flush` before function quit in case of Lambda freeze.
+                    _meter_provider.force_flush(rem)
+                except Exception:  # pylint: disable=broad-except
+                    logger.exception(
+                        f"MeterProvider failed to flush metrics"
+                    )
+        else:
+            logger.warning(
+                "MeterProvider was missing `force_flush` method. This is necessary in case of a Lambda freeze and would exist in the OTel SDK implementation."
             )
 
         return result
@@ -385,6 +410,7 @@ def _instrument(self, **kwargs):
         Args:
             **kwargs: Optional arguments
                 ``tracer_provider``: a TracerProvider, defaults to global
+                ``meter_provider``: a MeterProvider, defaults to global
                 ``event_context_extractor``: a method which takes the Lambda
                     Event as input and extracts an OTel Context from it. By default,
                     the context is extracted from the HTTP headers of an API Gateway
@@ -432,6 +458,7 @@ def _instrument(self, **kwargs):
             ),
             tracer_provider=kwargs.get("tracer_provider"),
             disable_aws_context_propagation=disable_aws_context_propagation,
+            meter_provider=kwargs.get("meter_provider"),
         )
 
     def _uninstrument(self, **kwargs):