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Putting metrics fails when POWERTOOLS_METRICS_NAMESPACE is not set #1500
Description
Putting metrics will fail with an software.amazon.cloudwatchlogs.emf.exception.InvalidNamespaceException when environment POWERTOOLS_METRICS_NAMESPACE is not set.
What were you trying to accomplish?
After updating cloudwatchlogs-aws-embedded-metrics to 4.1.1 I started to get InvalidNamespaceException when I try to put a metric for example using
MetricsUtils.withSingleMetric("MyMetric, 1.0, Unit.COUNT, metric ->
...
});
Expected Behavior
Possible behaviors I would expect are:
- metric is put with a default namespace
- no exception is thrown (maybe some internal logging). I would not expect a call to a metrics helper to fail my application with an unchecked exception
Current Behavior
software.amazon.cloudwatchlogs.emf.exception.InvalidNamespaceException is thrown which is an unchecked expception.
The reason is that MetricsUtils sets the namespace to an empty string when the environment variable is not set:
private static String defaultNameSpace() {
MetricsContext context = MetricsLoggerHelper.metricsContext();
return "aws-embedded-metrics".equals(context.getNamespace()) ?
SystemWrapper.getenv("POWERTOOLS_METRICS_NAMESPACE") : context.getNamespace();
}
Possible Solution
- Keep the original default namespace (
aws-embedded-metrics) ifPOWERTOOLS_METRICS_NAMESPACEis not set - Choose another "default" namespace if
POWERTOOLS_METRICS_NAMESPACEis not set
Steps to Reproduce (for bugs)
- Call
MetricsUtils.withSingleMetric()whithout providing a namespace inPOWERTOOLS_METRICS_NAMESPACE
Environment
- Powertools for AWS Lambda (Java) version used: 1.17.0
- Packaging format (Layers, Maven/Gradle): Gradle
- AWS Lambda function runtime: Java 17 (actually discovered in a unit test)
- Debugging logs
Activity
scottgerring commentedon Nov 7, 2023
Hey @roamingthings , thanks for the report! The requirement for the variable is documented, but it does seem a bit odd to explicitly 1/ check if the default hasn't been overriden, and then 2/ override it with an empty string. Inverting the whole thing as you suggest so we override if we have the env var, or use the default otherwise, seems more sensible, and wouldn't be a breaking change.
What do you think @jeromevdl - ?
jeromevdl commentedon Nov 7, 2023
First, I didn't really understand this code:
Looks to me that we should do the contrary: if the env var is empty, set a default, as you suggest.
But I'm not sure how the context namespace is actually set. I've found this which makes me think that
"aws-embedded-metrics"is the default. So if it is the default, we try to replace it with the env var, otherwise, it means the user already changed the default somehow (how?) and we should use that.What is missing here is the check on
SystemWrapper.getenv("POWERTOOLS_METRICS_NAMESPACE". If null or empty, we should come back to the default.fix #1500
github-actions commentedon Nov 16, 2023
This is now released under 1.18.0 version!
fix #1500 (#1506)
docs: HelloWorldStreamFunction in examples fails with sam (#1532)
chore(v2): Merge down from main (#1574)
fix aws-powertools#1500 (aws-powertools#1506)