Error 'datadog:api key not configured' when using apiKeySecretArn

[aline-camargo]

Expected Behavior

Sending monitoring data without logging errors, as it is configured according to documentation.

Actual Behavior

On every instance start we are getting this datadog:api key not configured error. All APM data and logs are being sent normally, but I believe this behavior of throwing error is not expected, as it was a false warning.

When I changed my code to use the apiKey parameter instead of apiKeySecretArn the error stoped showing.

Steps to Reproduce the Problem

1. Pass the key to dd extension using the apiKeySecretArn parameter
2. Observe the error log on every instance start

Specifications

• Serverless Framework version: 2.72.2
• Datadog Serverless Plugin version: 3.7.1
• Lambda function runtime (Python 3.7, Node 10, etc.): Node 14

Stacktrace

2022-03-08T13:22:09.277Z	undefined	ERROR	{"status":"error","message":"datadog:api key not configured, see https://dtdg.co/sls-node-metrics"}

[tianchu]

@astuyve I think we should also logDebug if this.isAgentRunning (similar to when forwarder is used, in this case, extension should check for the api key, not this library) https://github.com/DataDog/datadog-lambda-js/blob/436650bad8f544332ac45767a4b202c2ee36e312/src/metrics/listener.ts#L186