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99 lines
2.8 KiB
Go
99 lines
2.8 KiB
Go
package digest
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import (
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"crypto/tls"
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"encoding/base64"
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"encoding/json"
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"errors"
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"fmt"
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"github.com/containrrr/watchtower/pkg/registry/auth"
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"github.com/containrrr/watchtower/pkg/registry/manifest"
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"github.com/containrrr/watchtower/pkg/types"
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"github.com/sirupsen/logrus"
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"net/http"
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"strings"
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)
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// ContentDigestHeader is the key for the key-value pair containing the digest header
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const ContentDigestHeader = "Docker-Content-Digest"
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// CompareDigest ...
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func CompareDigest(container types.Container, registryAuth string) (bool, error) {
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var digest string
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registryAuth = TransformAuth(registryAuth)
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token, err := auth.GetToken(container, registryAuth)
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if err != nil {
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return false, err
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}
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digestURL, err := manifest.BuildManifestURL(container)
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if err != nil {
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return false, err
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}
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if digest, err = GetDigest(digestURL, token); err != nil {
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return false, err
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}
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logrus.WithField("remote", digest).Debug("Found a remote digest to compare with")
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for _, dig := range container.ImageInfo().RepoDigests {
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localDigest := strings.Split(dig, "@")[1]
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fields := logrus.Fields{"local": localDigest, "remote": digest}
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logrus.WithFields(fields).Debug("Comparing")
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if localDigest == digest {
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logrus.Debug("Found a match")
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return true, nil
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}
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}
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return false, nil
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}
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// TransformAuth from a base64 encoded json object to base64 encoded string
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func TransformAuth(registryAuth string) string {
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b, _ := base64.StdEncoding.DecodeString(registryAuth)
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credentials := &types.RegistryCredentials{}
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_ = json.Unmarshal(b, credentials)
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if credentials.Username != "" && credentials.Password != "" {
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ba := []byte(fmt.Sprintf("%s:%s", credentials.Username, credentials.Password))
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registryAuth = base64.StdEncoding.EncodeToString(ba)
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}
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return registryAuth
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}
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// GetDigest from registry using a HEAD request to prevent rate limiting
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func GetDigest(url string, token string) (string, error) {
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tr := &http.Transport{
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TLSClientConfig: &tls.Config{InsecureSkipVerify: true},
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}
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client := &http.Client{Transport: tr}
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if token != "" {
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logrus.WithField("token", token).Trace("Setting request token")
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} else {
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return "", errors.New("could not fetch token")
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}
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req, _ := http.NewRequest("HEAD", url, nil)
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req.Header.Add("Authorization", token)
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req.Header.Add("Accept", "application/vnd.docker.distribution.manifest.v2+json")
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req.Header.Add("Accept", "application/vnd.docker.distribution.manifest.list.v2+json")
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req.Header.Add("Accept", "application/vnd.docker.distribution.manifest.v1+json")
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logrus.WithField("url", url).Debug("Doing a HEAD request to fetch a digest")
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res, err := client.Do(req)
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if err != nil {
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return "", err
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}
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if res.StatusCode != 200 {
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return "", fmt.Errorf("registry responded to head request with %d", res.StatusCode)
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}
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return res.Header.Get(ContentDigestHeader), nil
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}
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