Explore options for AWS Lambda instrumentation

[kford-newrelic]

Description

Intention is that we provide the ability to instrument AWS Lambda functions. Need to identify the best way to achieve that; is it using the existing Ruby agent - perhaps in lite mode? Some other component?

Acceptance Criteria

• Needs to power our current APM experience.
• Needs to have a Lambda Layers deliverable

Design Consideration/Limitations

N/A

Dependencies

TBD

Additional context

Research spike. After determining what's feasible, we should identify the work needed in the future.

[workato-integration]

https://new-relic.atlassian.net/browse/NR-191078

[fallwith]

Here's where we're at currently for alignment with the existing NR Lambda spec:

Complete

• The absence of a config file should be expected and not warned about
• The absence of a license key should be expected and not disable any agent functionality
• The preconnect and connect actions should be skipped
• The actions to connect to the collector and relay POST requests should be modified and JSON blobs should be written out locally instead
• The JSON blobs must be formatted in a specific way with additional Lamdba specific metadata and always utilize compression
• The presence of a function name environment variable must force serverless mode to be enabled
• The presence of a standard NR output file location should be detected and overwrite the STDOUT output default
• An apdex_t value must be permitted to be set via an environment variable

In Progress

• A lambda_handler API must exist to process the AWS context object
• Need to map 2 event types to WebTransaction and all others to Other
• For web requests, parse out HTTP info from both the request and response
• Extract event source information. Successfully extracted info goes in the metadata hash. Other info is omitted from the hash.
• Cold start detection
• Distributed tracing support via 3 new environment variables
• Apply adaptive sampling with target (10) and target period in seconds (60) values

[fallwith]

All agent work is now ready for review with 2474. Other NR repos for Lambda and documentation will still need to be updated.

[fallwith]

The original scope of this one has been satisfied. We're code complete and will track testing, documentation, and updates to relevant CI/CD repos separately with other issues.