image-checker/main.go
2025-07-17 03:04:35 +02:00

95 lines
2.3 KiB
Go

package main
import (
"context"
"fmt"
"log"
"regexp"
"strings"
"github.com/docker/docker/api/types/image"
"github.com/docker/docker/client"
"github.com/regclient/regclient"
"github.com/regclient/regclient/types/ref"
)
// Wandelt ein ImageTag in registrykompatibles Format (ggf. registry hinzufügen)
func toRegistryImage(imageTag string) (string, error) {
r := regexp.MustCompile(`^(?:(?P<registry>[^/]+)/)?(?P<repo>[^:]+)(?::(?P<tag>.+))?$`)
match := r.FindStringSubmatch(imageTag)
if len(match) == 0 {
return "", fmt.Errorf("Image-Tag nicht erkannt: %s", imageTag)
}
registry := match[r.SubexpIndex("registry")]
repo := match[r.SubexpIndex("repo")]
tag := match[r.SubexpIndex("tag")]
if registry == "" {
registry = "registry-1.docker.io"
}
if tag == "" {
tag = "latest"
}
return fmt.Sprintf("%s/%s:%s", registry, repo, tag), nil
}
// Extrahiert nur den reinen sha256:<...>-Digest
func extractDigest(s string) string {
for _, part := range strings.Split(s, "@") {
if strings.HasPrefix(part, "sha256:") {
return part
}
}
return s // ggf. nur die ID, wenn kein Digest
}
func main() {
ctx := context.Background()
cli, err := client.NewClientWithOpts(client.FromEnv)
if err != nil {
log.Fatal(err)
}
defer cli.Close()
rc := regclient.New()
images, err := cli.ImageList(ctx, image.ListOptions{All: true})
if err != nil {
log.Fatal(err)
}
for _, img := range images {
for _, tag := range img.RepoTags {
imageRef, err := toRegistryImage(tag)
if err != nil {
continue
}
// Lokalen Digest extrahieren
var localDigest string
if len(img.RepoDigests) > 0 {
localDigest = extractDigest(img.RepoDigests[0])
} else {
localDigest = img.ID
}
// Remote-Digest bestimmen
refObj, err := ref.New(imageRef)
if err != nil {
fmt.Printf("ImageRef-Fehler bei %s: %v\n", tag, err)
continue
}
desc, err := rc.ManifestHead(ctx, refObj)
if err != nil {
fmt.Printf("Manifest nicht gefunden (%s): %v\n", tag, err)
continue
}
remoteDigest := desc.GetDigest().String()
fmt.Printf("Image: %s\n Local Digest: %s\n Remote Digest: %s\n", tag, localDigest, remoteDigest)
if localDigest == remoteDigest {
fmt.Println(" -> Kein Update verfügbar.")
} else {
fmt.Println(" -> Update verfügbar!")
}
}
}
}