Closed
Description
Expected Behaviour
When uploading a custom metric using the aws_lambda_powertools.metrics package, the metrics should appear in CloudWatch Metrics.
Current Behaviour
Metrics appear intermittently and appear to be tied to whether a lambda was cold started (and also had a cold start metric uploaded).
Code snippet
Split route handler:
metrics: Metrics = Metrics()
@router.delete("/v1/asset", cors=True)
@tracer.capture_method
def delete_asset() -> dict:
metrics.add_metric(name="AssetDeleted", unit=MetricUnit.Count, value=1)
return {"message": "Asset deletion successful"}
Lambda handler:
@metrics.log_metrics(capture_cold_start_metric=True)
@logger.inject_lambda_context(correlation_id_path=correlation_paths.API_GATEWAY_REST, log_event=True)
@tracer.capture_lambda_handler
@auth.enforce_allow_list
@auth.restrict_api_key
def lambda_handler(event: Dict, context: LambdaContext):
return app.resolve(event, context)Possible Solution
When examining the cloudwatch logs, the unsuccessful metrics appear in the same log line as the tracer log, for example:
{
"resource": "/v1/asset",
"path": "/v1/asset",
"httpMethod": "DELETE",
...more data...
}{
"_aws": {
"Timestamp": 1672800187055,
"CloudWatchMetrics": [
{
"Namespace": "MyNamespace",
"Dimensions": [
[
"service"
]
],
"Metrics": [
{
"Name": "AssetDeleted",
"Unit": "Count"
}
]
}
]
},
"service": "MyLambda",
"AssetDeleted": [
1
]
}
When successful metrics appear (such as when they are uploaded as part of a cold start), they appear in their own log line in CloudWatch and are presumably parsed.
Steps to Reproduce
- Create a split route lambda handler, log cold starts
- In the split route(s) attempt to create/upload custom metrics
- Observe not all metrics appear in CloudWatch metrics as expected
AWS Lambda Powertools for Python version
latest
AWS Lambda function runtime
3.6
Packaging format used
PyPi
Debugging logs
No response