include build info in Prometheus metrics (#22819)

Related to: https://github.com/go-gitea/gitea/issues/18061

This PR adds build info to the Prometheus metrics. This includes:
- goarch: https://pkg.go.dev/runtime#GOARCH
- goos: https://pkg.go.dev/runtime#pkg-constants
- goversion: https://pkg.go.dev/runtime#Version
- gitea version: just exposes the existing
code.gitea.io/gitea/modules/setting.AppVer

It's a similar approach to what some other Golang projects are doing,
e.g. Prometheus:
https://github.com/prometheus/common/blob/main/version/info.go

example /metrics response from Prometheus:
```
# HELP prometheus_build_info A metric with a constant '1' value labeled by version, revision, branch, goversion from which prometheus was built, and the goos and goarch for the build.
# TYPE prometheus_build_info gauge
prometheus_build_info{branch="HEAD",goarch="amd64",goos="linux",goversion="go1.19.4",revision="c0d8a56c69014279464c0e15d8bfb0e153af0dab",version="2.41.0"} 1
```

/metrics response from gitea with this PR:
```
# HELP gitea_build_info Build information
# TYPE gitea_build_info gauge
gitea_build_info{goarch="amd64",goos="linux",goversion="go1.20",version="2c6cc0b8c"} 1
```

Signed-off-by: Michal Wasilewski <mwasilewski@gmx.com>

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Signed-off-by: Michal Wasilewski <mwasilewski@gmx.com>
This commit is contained in:
Michal 2023-02-08 18:54:01 +01:00 committed by GitHub
parent 7d3c4c3e8a
commit 5ae07d4c2f
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@ -4,7 +4,10 @@
package metrics
import (
"runtime"
activities_model "code.gitea.io/gitea/models/activities"
"code.gitea.io/gitea/modules/setting"
"github.com/prometheus/client_golang/prometheus"
)
@ -17,6 +20,7 @@ type Collector struct {
Accesses *prometheus.Desc
Actions *prometheus.Desc
Attachments *prometheus.Desc
BuildInfo *prometheus.Desc
Comments *prometheus.Desc
Follows *prometheus.Desc
HookTasks *prometheus.Desc
@ -62,6 +66,16 @@ func NewCollector() Collector {
"Number of Attachments",
nil, nil,
),
BuildInfo: prometheus.NewDesc(
namespace+"build_info",
"Build information",
[]string{
"goarch",
"goos",
"goversion",
"version",
}, nil,
),
Comments: prometheus.NewDesc(
namespace+"comments",
"Number of Comments",
@ -195,6 +209,7 @@ func (c Collector) Describe(ch chan<- *prometheus.Desc) {
ch <- c.Accesses
ch <- c.Actions
ch <- c.Attachments
ch <- c.BuildInfo
ch <- c.Comments
ch <- c.Follows
ch <- c.HookTasks
@ -241,6 +256,15 @@ func (c Collector) Collect(ch chan<- prometheus.Metric) {
prometheus.GaugeValue,
float64(stats.Counter.Attachment),
)
ch <- prometheus.MustNewConstMetric(
c.BuildInfo,
prometheus.GaugeValue,
1,
runtime.GOARCH,
runtime.GOOS,
runtime.Version(),
setting.AppVer,
)
ch <- prometheus.MustNewConstMetric(
c.Comments,
prometheus.GaugeValue,