Provide binders for Git and Build information

[mafr]

Description
There has been some discussion at the Spring Boot project about exposing information like the Git commit ID and Maven coordinates as metrics, similar in style to the existing JvmInfoMetrics binder. For consistency, we would provide the same information that Spring Boot's Actuator exposes on its /actuator/info endpoint.

The binders would receive the data via constructor arguments and add a constant gauge with tags for all attributes we want to expose. If some values are null, we would add a marker string ("unknown", "null", "N/A") to make sure all tags are always present.

Example:

git_info{app="some-service", branch="main", id="cafecafe", time="2022-04-26T18:39:18Z"} 1.0
build_info{app="some-service", name="Some Service", artifact="some-service", group="org.example", version="1.7", time="2022-04-28T12:01:07Z"} 1.0

This issue is intended to discuss whether this is a worthwhile addition and to discuss the design if the team decides to proceed.

Rationale
Adding metrics binders to Micrometer would provide standardization of these metrics across all users of Micrometer, not just Spring Boot. The new metrics would be useful in Grafana dashboards, for example, to display which exact commit/version is currently deployed.

Additional context

• PR 30628 at Spring Boot
• GitProperties
• BuildProperties

[jonatan-ivanov]

@shakuzen fyi

[jonatan-ivanov]

@mafr Would you be up to opening a PR for this in Micrometer?
It would be somewhat similar to the PR you opened for Boot, except we could copy the whole/partial GitProperties/BuildProperties classes.
Then once Micrometer has this, we can add auto-configuration to Boot.

[ardetrick]

Hi @jonatan-ivanov - I've never made a contribution here before but I saw the "help wanted" tag and figured I would give it a try. Would appreciate your opinion on my PR and if it meets the desires and goals of this issue. Thanks!

[ardetrick]

Hi @jonatan-ivanov and @shakuzen - was wondering if either of you would be willing to take a look the PR I opened for this issue. Would great appreciate your opinions or an update on if this change is still of interest to micrometer. Thanks!

[marcingrzejszczak]

@ardetrick we will look into this ASAP, sorry for the big delay

[ardetrick]

Thanks @marcingrzejszczak - I know this is a busy time of the year but I eagerly await your team's feedback when you get a chance to take a look.

[ardetrick]

@marcingrzejszczak just want to put this back on you radar - thanks!