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fix: use configuration-revision for current_rev in flake info metric

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The nixos_flake_info metric's current_rev label was incorrectly showing
the nixpkgs input revision (from /run/current-system/nixos-version)
instead of the flake's own revision.

Now reads from /run/current-system/configuration-revision which contains
the flake's self.rev when system.configurationRevision is set in the
NixOS configuration.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
This commit is contained in:
Torjus Håkestad
2026-02-07 00:27:38 +01:00
parent 9c29505814
commit 86eaeb4b2a
3 changed files with 11 additions and 89 deletions
Download Patch File Download Diff File Expand all files Collapse all files

21
collector/flake.go
View File

@@ -7,7 +7,6 @@ import (
"log/slog" "log/slog"
"os" "os"
"os/exec" "os/exec"
"regexp"
"strings" "strings"
"sync" "sync"
"time" "time"
@@ -15,11 +14,7 @@ import (
"github.com/prometheus/client_golang/prometheus" "github.com/prometheus/client_golang/prometheus"
) )
const nixosVersionPath = "/run/current-system/nixos-version" const configRevisionPath = "/run/current-system/configuration-revision"
// revisionPattern extracts the git hash from nixos-version.
// Formats: "25.11.20260203.e576e3c" or "1994-294a625"
var revisionPattern = regexp.MustCompile(`[.-]([a-f0-9]{7,40})$`)
type FlakeCollector struct { type FlakeCollector struct {
flakeURL string flakeURL string
@@ -215,18 +210,16 @@ func fetchFlakeMetadata(flakeURL string) (*flakeMetadata, error) {
} }
func getCurrentSystemRevision() (string, error) { func getCurrentSystemRevision() (string, error) {
data, err := os.ReadFile(nixosVersionPath) data, err := os.ReadFile(configRevisionPath)
if err != nil { if err != nil {
if os.IsNotExist(err) {
// configuration-revision doesn't exist; user hasn't set system.configurationRevision
return "", nil
}
return "", err return "", err
} }
version := strings.TrimSpace(string(data)) rev := strings.TrimSpace(string(data))
matches := revisionPattern.FindStringSubmatch(version)
if matches == nil {
return "", nil
}
rev := matches[1]
if len(rev) > 7 { if len(rev) > 7 {
rev = rev[:7] rev = rev[:7]
} }

77
collector/flake_test.go
View File

@@ -3,40 +3,13 @@ package collector
import ( import (
"encoding/json" "encoding/json"
"os" "os"
"path/filepath"
"testing" "testing"
) )
func TestRevisionPattern(t *testing.T) {
tests := []struct {
version string
wantRev string
}{
{"25.11.20260203.e576e3c", "e576e3c"},
{"1994-294a625", "294a625"},
{"25.05.20250101.abcdef1234567890", "abcdef1234567890"},
{"no-revision-here", ""},
{"", ""},
}
for _, tt := range tests {
t.Run(tt.version, func(t *testing.T) {
matches := revisionPattern.FindStringSubmatch(tt.version)
var got string
if matches != nil {
got = matches[1]
}
if got != tt.wantRev {
t.Errorf("revisionPattern.FindStringSubmatch(%q) = %q, want %q", tt.version, got, tt.wantRev)
}
})
}
}
func TestGetCurrentSystemRevision(t *testing.T) { func TestGetCurrentSystemRevision(t *testing.T) {
// Skip if not on NixOS // Skip if not on NixOS with system.configurationRevision set
if _, err := os.Stat(nixosVersionPath); os.IsNotExist(err) { if _, err := os.Stat(configRevisionPath); os.IsNotExist(err) {
t.Skip("not running on NixOS") t.Skip("not running on NixOS with system.configurationRevision set")
} }
rev, err := getCurrentSystemRevision() rev, err := getCurrentSystemRevision()
@@ -48,50 +21,6 @@ func TestGetCurrentSystemRevision(t *testing.T) {
t.Logf("current system revision: %s", rev) t.Logf("current system revision: %s", rev)
} }
func TestGetCurrentSystemRevisionFromFile(t *testing.T) {
// Create a temp file to simulate /run/current-system/nixos-version
dir := t.TempDir()
versionPath := filepath.Join(dir, "nixos-version")
tests := []struct {
content string
wantRev string
}{
{"25.11.20260203.e576e3c\n", "e576e3c"},
{"1994-294a625\n", "294a625"},
{"25.05.20250101.abcdef1234567890\n", "abcdef1"},
{"no-hash", ""},
}
for _, tt := range tests {
t.Run(tt.content, func(t *testing.T) {
if err := os.WriteFile(versionPath, []byte(tt.content), 0644); err != nil {
t.Fatal(err)
}
// We can't easily test the actual function without modifying the constant,
// so we test the pattern extraction logic directly
version := tt.content
if len(version) > 0 && version[len(version)-1] == '\n' {
version = version[:len(version)-1]
}
matches := revisionPattern.FindStringSubmatch(version)
var rev string
if matches != nil {
rev = matches[1]
if len(rev) > 7 {
rev = rev[:7]
}
}
if rev != tt.wantRev {
t.Errorf("got revision %q, want %q", rev, tt.wantRev)
}
})
}
}
func TestFlakeLocksUnmarshal(t *testing.T) { func TestFlakeLocksUnmarshal(t *testing.T) {
jsonData := `{ jsonData := `{
"revision": "abc1234567890", "revision": "abc1234567890",

2
main.go
View File

@@ -15,7 +15,7 @@ import (
"github.com/prometheus/client_golang/prometheus/promhttp" "github.com/prometheus/client_golang/prometheus/promhttp"
) )
const version = "0.2.0" const version = "0.2.1"
func main() { func main() {
cfg, err := config.Parse() cfg, err := config.Parse()