feat: add version collector (pve_version_info)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

collector/fixtures/version.json

@@ -0,0 +1 @@
+{"data":{"version":"9.1.4","release":"9.1","repoid":"5ac30304265fbd8e"}}

collector/version.go

@@ -0,0 +1,59 @@
+package collector
+
+import (
+	"encoding/json"
+	"fmt"
+	"log/slog"
+
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+func init() {
+	registerCollector("version", func(logger *slog.Logger) Collector {
+		return newVersionCollector(logger)
+	})
+}
+
+type versionCollector struct {
+	logger *slog.Logger
+}
+
+func newVersionCollector(logger *slog.Logger) *versionCollector {
+	return &versionCollector{logger: logger}
+}
+
+type versionResponse struct {
+	Data struct {
+		Version string `json:"version"`
+		Release string `json:"release"`
+		RepoID  string `json:"repoid"`
+	} `json:"data"`
+}
+
+func (c *versionCollector) Update(client *Client, ch chan<- prometheus.Metric) error {
+	body, err := client.Get("/version")
+	if err != nil {
+		return fmt.Errorf("failed to get /version: %w", err)
+	}
+
+	var resp versionResponse
+	if err := json.Unmarshal(body, &resp); err != nil {
+		return fmt.Errorf("failed to parse /version response: %w", err)
+	}
+
+	ch <- prometheus.MustNewConstMetric(
+		prometheus.NewDesc(
+			prometheus.BuildFQName(namespace, "", "version_info"),
+			"Proxmox VE version information.",
+			[]string{"release", "repoid", "version"},
+			nil,
+		),
+		prometheus.GaugeValue,
+		1,
+		resp.Data.Release,
+		resp.Data.RepoID,
+		resp.Data.Version,
+	)
+
+	return nil
+}

collector/version_test.go

@@ -0,0 +1,32 @@
+package collector
+
+import (
+	"log/slog"
+	"strings"
+	"testing"
+
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/testutil"
+)
+
+func TestVersionCollector(t *testing.T) {
+	client := newTestClient(t, map[string]string{
+		"/version": "version.json",
+	})
+
+	collector := newVersionCollector(slog.Default())
+	adapter := &testCollectorAdapter{client: client, collector: collector}
+
+	reg := prometheus.NewRegistry()
+	reg.MustRegister(adapter)
+
+	expected := `
+# HELP pve_version_info Proxmox VE version information.
+# TYPE pve_version_info gauge
+pve_version_info{release="9.1",repoid="5ac30304265fbd8e",version="9.1.4"} 1
+`
+
+	if err := testutil.GatherAndCompare(reg, strings.NewReader(expected), "pve_version_info"); err != nil {
+		t.Errorf("unexpected metrics: %s", err)
+	}
+}

go.mod

@@ -17,6 +17,7 @@ require (
 	github.com/golang-jwt/jwt/v5 v5.3.0 // indirect
 	github.com/google/uuid v1.6.0 // indirect
 	github.com/jpillora/backoff v1.0.0 // indirect
+	github.com/kylelemons/godebug v1.1.0 // indirect
 	github.com/mdlayher/socket v0.4.1 // indirect
 	github.com/mdlayher/vsock v1.2.1 // indirect
 	github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 // indirect