can buildevents cmd capture stdout / stderr on failed spans?

[estraph]

Is your feature request related to a problem? Please describe.
I've been trying out buildevents in GitHub actions and have been using buildevents cmd to run a number of shell commands, and send them as spans to Honeycomb. When a span has an error, it seems that while the exit code is captured as a span attribute, the actual error output (stdout or stderr) is not.

Describe the solution you'd like
From using other opentelelemtry and honeycomb libraries it seems useful to include the error message on the span. I would love to see the cmd command not just pass through stdout and stderr but also include them on a the span if the command exits with an error.

Describe alternatives you've considered
I've very briefly considered using tee to output errors to a file, detecting non-zero exit codes and including the output as an attribute via the BUILDEVENT_FILE. This would add a lot of boilerplate to my workflows, though - which are already a bit bloated through the instrumentation as it is.

Additional context
I've been enjoying this tool otherwise, thanks for making a great product and helping to instrument CI 🚀

[brookesargent]

Thank you for submitting this issue, @estraph! This is a great suggestion, I'll move it along to be prioritized in our backlog.