caddy: `go_build_info` version

[jpds]

Nixpkgs version

• Unstable (25.11)

Describe the bug

Caddy's go_build_info metric currently returns version=(devel) and doesn't seem to use the version specified here:

• nixpkgs/pkgs/by-name/ca/caddy/package.nix

  Line 39 in 5200ef0

  "-X github.com/caddyserver/caddy/v2.CustomVersion=${version}"

I've tried various combinations of version.Version=${version} and nothing seems to cause this metric label to change.

Steps to reproduce

N/A

Expected behaviour

N/A

Screenshots

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Relevant log output

Additional context

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System metadata

N/A

Notify maintainers

@Br1ght0ne @stepbrobd @techknowlogick @ryan4yin

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[stepbrobd]

is this an upstream issue? i saw you opened caddyserver/caddy#5653 a good while back but there don't seem to be a solution

[stepbrobd]

this behavior is documented here: https://pkg.go.dev/github.com/prometheus/client_golang/prometheus/collectors#NewBuildInfoCollector

i tried the something with the official binary release, and the same problem persists:

$ cat caddyfile
{
    metrics
}
$ ./caddy_2.10.2_mac_arm64/caddy run --config caddyfile --adapter caddyfile
$ curl -s http://localhost:2019/metrics | grep go_build_info
# HELP go_build_info Build information about the main Go module.
# TYPE go_build_info gauge
go_build_info{checksum="",path="caddy",version="(devel)"} 1

as a temporary solution, you could write a patch to replace https://github.com/caddyserver/caddy/blob/551f793700fe1550845c824470b623fd1aa03d36/context.go#L112 collectors.NewBuildInfoCollector() to a custom build info collector to read from "-X github.com/caddyserver/caddy/v2.CustomVersion=${version}"

im closing this as this is a upstream bug