X-Ray UDP Trace Client needed

[ahornbeck]

Describe the feature

Support for UDP transport of X-Ray traces is needed to support the X-Ray daemon.

Use Case

AWS Lambda provides a service-managed X-Ray daemon for batching X-Ray requests locally before forwarding them to the X-Ray service. The daemon listens on UDP port 2000 but there is no X-Ray UDP trace client. Therefore there is no way to leverage the local X-Ray daemon using this SDK.

Using the existing X-Ray client (HTTPS), it can take 40ms to 3000ms+ for each request (default Lambda timeout kill process at this point). Latency is highest for the initial request. The latency introduced by the HTTPS X-Ray client makes it unusable in Lambda functions. An extreme case of measuring a thing, altering a thing.

A workaround is to open a UDP socket bound to 0.0.0.0:0 and send to the address found in the AWS_XRAY_DAEMON_ADDRESS env var. For comparison, sending via a UDP socket takes less than 1ms.

Proposed Solution

Provide a UDP-specific client for sending trace data.

Other Information

No response

Acknowledgements

• I may be able to implement this feature request
• This feature might incur a breaking change

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[Velfi]

Thanks for submitting this request @ahornbeck. This sounds like a pretty important feature for customers using XRay in Lambdas.

[rafalwrzeszcz]

In the meantime if anyone needs that (like I do) - I'm using https://github.com/softprops/xray ; it requires custom binding unfortunately, as it only offers data structures and UDP client itself but… works.

[rafalwrzeszcz]

I've spent some time to integrate tracing spans generated by SDK with mentioned above X-Ray UDP client - feel free to try out https://wrzasq.pl/blog/x-ray-tracing-for-aws-rust-sdk-in-lambda-runtime.html