Only get specific BEP events with -build_event_json_file

[EitoWayve80]

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Description of the problem / feature request:

I want to get the uuid of the BuildStarted BEP event of a large CI build, so I am currently doing this by adding the -build_event_json_file flag to my runs and extracting the data from there, by reading the head of the built event json file and saving that. (BuildStarted is the first BEP event in the build event json).

However, a lot of the builds unfortunately time out, due to the large amount of time writing the build event json file. I'd like to get rid of this behaviour where it tries to upload the full file. Is there any way of doing this? I couldn't find anything on this, and no response on slack

Feature request

If it doesn't exist already, could the flag -build_event_json_file include a way to only dump the json for certain events? E.g. I just want the BEP Json for BuildStarted event

What operating system are you running Bazel on?

Ubuntu 20.04.3

Any other information, logs, or outputs that you want to share?

• We use a bazel remote cache in AWS

[benjaminp]

One way to do this would be to send --build_event_json_file output to pipe instead of a file and connect a program that retains only the desired events.

[github-actions]

Thank you for contributing to the Bazel repository! This issue has been marked as stale since it has not had any activity in the last 1+ years. It will be closed in the next 14 days unless any other activity occurs or one of the following labels is added: "not stale", "awaiting-bazeler". Please reach out to the triage team (@bazelbuild/triage) if you think this issue is still relevant or you are interested in getting the issue resolved.