send activation_method only for 8.7.1+

[SylvainJuge]

Description

Only send the service.agent.activation_method when APM server is AT LEAST `8.7.1 or unknown (assume it's not 8.7.0 by default).

Specification changes: #780 #783

I found only the following agents are impacted as their code already reference this field: java, dotnet, nodejs and python

Agent Issues

• [x] https://github.com/elastic/apm-agent-java/issues/3088
• [x] https://github.com/elastic/apm-agent-dotnet/issues/2039
• [x] https://github.com/elastic/apm-agent-nodejs/issues/3230
• [x] https://github.com/elastic/apm-agent-python/issues/1786

[trentm]

FWIW, this likely means that a fast first Lambda invocation will not send activation_method in metadata, because it will have data to send on before the APM server version check request has time to respond.

[SylvainJuge]

That's a very good point, and it would also be problematic for all the features that depend on agent version.

• could the lambda extension help us here by being a proxy to the actual apm-server ?
• for lambdas that are deployed in production (and not executed only once), does it means we will have 99% of data with the field set and only the first few document that lack this field ? In this case I think it would be an acceptable compromise for this field.

[felixbarny]

Maybe it's better to optimistically assume that the APM Server version is not 8.7.0 and only disable sending activation_method when the version info request returns. As the bug that leads to document rejection only affects internal metrics which are, by default, scheduled every 30s, there's a good chance that we know about the version of the server before sending the first metrics.

[SylvainJuge]

+1 to send this field when the server version is unknown, and only explicitly omit it when we know it's 8.7.0. Do you think it's worth re-modify the spec for this small but important implementation detail ?

[felixbarny]

yes

[SylvainJuge]

second take for specification: PR #783

[SylvainJuge]

Closing this issue as all impacted agents have been updated.