OpenTelemetry's SDKs indeed don't collect payloads (HTTP request/response bodies, message queues content, DB queries and results, etc.) by default - but they do provide ways for customizing and enhancing the collected data.
In Node, for example, there are request and response hooks for doing just that (see in GitHub).
The Helios OpenTelemetry SDKs for various platforms (including Go, Java, Node.js, Python, Ruby and more) automatically take care of payload collection for you, so you don't have to implement those hooks yourself.
If needed, you can disable payload collection by using the metadata_only configuration.
Updated 2 months ago