Add metrics version

[withinboredom]

closes #1225

This adds a new global set by -X ld variable, VersionString which is injected during the Docker build. This can be fetched via the frankenphp_version labels, as well as the current php version reported.

[dunglas]

Maybe could you use https://pkg.go.dev/runtime/debug#ReadBuildInfo instead?

[withinboredom]

I'll take a look!

[dunglas]

Actually, the version of the FrankenPHP module (and of all other installed modules) should already be exposed by Caddy: https://github.com/caddyserver/caddy/blob/v2.8.4/metrics.go#L15

[withinboredom]

This is the string currently output from a production instance:

go_build_info{checksum="",path="github.com/dunglas/frankenphp/caddy",version="(devel)"} 1

It doesn't seem too useful :(

[dunglas]

Hum this looks like an issue in my release script 😅 (because of the replace). Isn't the version of lib (not the Caddy module) displayed?

[withinboredom]

I'm not sure what you mean, but that is the only thing in the metrics.

[dunglas]

I mean we should have the version of github.com/dunglas/frankenphp too

[withinboredom]

There are no dependencies listed, just the top-level.

[dunglas]

I think the best fix would be to update our release pipeline to:

• publish the new version of the github.com/dunglas/frankenphp module on pkg.go.dev
• publish the new version of the github.com/dunglas/frankenphp/caddy module depending on the updated github.com/dunglas/frankenphp module on pkg.go.dev
• build the binaries and the Docker images either using xcaddy, or a command depending on the newly released versions

[withinboredom]

It looks like it is already there: https://pkg.go.dev/github.com/dunglas/frankenphp/caddy

So, to get the version string to show up properly, we just need to change how we are building it, if I understand correctly?

[withinboredom]

Holy hell this was a rabbit hole. Apparently, prior to go 1.24, it was hardcoded to devel version unless it was installed via go install and only go install...

:sigh:

Since 1.24, it is now based on git tags when building locally:

# create tag on a branch with non-tracked files:
go_build_info{checksum="",path="github.com/dunglas/frankenphp/caddy",version="v1.4.3+dirty"}
# branch from main branch:
go_build_info{checksum="",path="github.com/dunglas/frankenphp/caddy",version="v1.4.2-0.20250215125226-cdbf1bd60113"}

So, do we want to upgrade from go 1.22 to 1.24 @dunglas?

[dunglas]

Sure! We'll upgrade to Go 1.24 as soon as dependencies (especially Caddy) are compatible with it.

[dunglas]

Now that we upgraded to Go 1.24, we get go_build_info{checksum="",path="caddy",version="v1.4.4+dirty"} 1 for the static binary.

It's indeed better. It would be nice to get rid of the +dirty part but I don't understand why it is added.

For the Docker image, we still get go_build_info{checksum="",path="github.com/dunglas/frankenphp/caddy",version="(devel)"} 1.