124 lines
2.9 KiB
Go
124 lines
2.9 KiB
Go
package main
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import (
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"context"
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"fmt"
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"log"
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"net/http"
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"regexp"
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"strings"
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"github.com/docker/docker/api/types/image"
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"github.com/docker/docker/client"
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"github.com/prometheus/client_golang/prometheus"
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"github.com/prometheus/client_golang/prometheus/promhttp"
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"github.com/regclient/regclient"
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"github.com/regclient/regclient/types/ref"
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)
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// Hilfsfunktion: registrykompatibles Format aus repo:tag erzeugen
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func toRegistryImage(imageTag string) (string, error) {
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r := regexp.MustCompile(`^(?:(?P<registry>[^/]+)/)?(?P<repo>[^:]+)(?::(?P<tag>.+))?$`)
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match := r.FindStringSubmatch(imageTag)
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if len(match) == 0 {
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return "", fmt.Errorf("Image-Tag nicht erkannt: %s", imageTag)
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}
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registry := match[r.SubexpIndex("registry")]
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repo := match[r.SubexpIndex("repo")]
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tag := match[r.SubexpIndex("tag")]
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if registry == "" {
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registry = "registry-1.docker.io"
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}
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if tag == "" {
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tag = "latest"
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}
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return fmt.Sprintf("%s/%s:%s", registry, repo, tag), nil
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}
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// Extrahiert nur den sha256:... Digest
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func extractDigest(s string) string {
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for _, part := range strings.Split(s, "@") {
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if strings.HasPrefix(part, "sha256:") {
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return part
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}
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}
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return s
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}
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// Prometheus Collector-Struktur
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type dockerImageUpdateCollector struct {
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desc *prometheus.Desc
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}
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func newDockerImageUpdateCollector() prometheus.Collector {
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return &dockerImageUpdateCollector{
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desc: prometheus.NewDesc(
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"docker_image_update_available",
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"Whether a new image digest is available for this local image tag (1=update, 0=current)",
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[]string{"image"},
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nil,
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),
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}
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}
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func (c *dockerImageUpdateCollector) Describe(ch chan<- *prometheus.Desc) {
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ch <- c.desc
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}
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func (c *dockerImageUpdateCollector) Collect(ch chan<- prometheus.Metric) {
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ctx := context.Background()
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cli, err := client.NewClientWithOpts(client.FromEnv)
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if err != nil {
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log.Println("Docker-Client-Fehler:", err)
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return
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}
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defer cli.Close()
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rc := regclient.New()
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images, err := cli.ImageList(ctx, image.ListOptions{All: true})
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if err != nil {
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log.Println("Docker-ImageList-Fehler:", err)
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return
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}
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for _, img := range images {
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for _, tag := range img.RepoTags {
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imageRef, err := toRegistryImage(tag)
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if err != nil {
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continue
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}
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var localDigest string
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if len(img.RepoDigests) > 0 {
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localDigest = extractDigest(img.RepoDigests[0])
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} else {
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localDigest = img.ID
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}
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refObj, err := ref.New(imageRef)
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if err != nil {
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continue
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}
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desc, err := rc.ManifestHead(ctx, refObj)
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if err != nil {
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continue
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}
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remoteDigest := desc.GetDigest().String()
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var value float64 = 0
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if localDigest != remoteDigest {
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value = 1
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}
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ch <- prometheus.MustNewConstMetric(
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c.desc,
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prometheus.GaugeValue,
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value,
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tag,
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)
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}
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}
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}
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func main() {
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prometheus.MustRegister(newDockerImageUpdateCollector())
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http.Handle("/metrics", promhttp.Handler())
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log.Println("Prometheus Exporter läuft auf :9888/metrics")
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log.Fatal(http.ListenAndServe(":9888", nil))
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}
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