Prevent duplicate entries in .docker/config.json

cmd/build-init/main.go

@@ -55,7 +55,7 @@ func main() {
 	}
 
 	remoteImageFactory := &registry.ImageFactory{
-		KeychainFactory: defaultKeychainFactory{},
+		KeychainFactory: keychainFactory{builderCreds},
 	}
 
 	filePermissionSetup := &cnb.FilePermissionSetup{
@@ -76,11 +76,12 @@ func main() {
 	}
 }
 
-type defaultKeychainFactory struct {
+type keychainFactory struct {
+	keychain authn.Keychain
 }
 
-func (defaultKeychainFactory) KeychainForImageRef(registry.ImageRef) authn.Keychain {
-	return authn.DefaultKeychain
+func (k keychainFactory) KeychainForImageRef(registry.ImageRef) authn.Keychain {
+	return k.keychain
 }
 
 type realOs struct {
@@ -89,15 +90,3 @@ type realOs struct {
 func (realOs) Chown(volume string, uid, gid int) error {
 	return os.Chown(volume, uid, gid)
 }
-
-func fileExists(file string, logger *log.Logger) bool {
-	_, err := os.Stat(file)
-	if err != nil {
-		if os.IsNotExist(err) {
-			return false
-		}
-		logger.Fatal(err.Error())
-	}
-
-	return true
-}

pkg/dockercreds/docker_creds.go

@@ -2,11 +2,13 @@ package dockercreds
 
 import (
 	"encoding/json"
-	"github.com/pkg/errors"
 	"io/ioutil"
+	"net/url"
+	"strings"
 
 	"github.com/google/go-containerregistry/pkg/authn"
 	"github.com/google/go-containerregistry/pkg/name"
+	"github.com/pkg/errors"
 )
 
 type DockerCreds map[string]entry
@@ -36,7 +38,11 @@ func (c DockerCreds) AppendToDockerConfig(path string) error {
 		return err
 	}
 
-	appendedCreds := c.append(existingCreds)
+	appendedCreds, err := existingCreds.append(c)
+	if err != nil {
+		return err
+	}
+
 	configJson := dockerConfigJson{
 		Auths: appendedCreds,
 	}
@@ -47,15 +53,41 @@ func (c DockerCreds) AppendToDockerConfig(path string) error {
 	return ioutil.WriteFile(path, configJsonBytes, 0600)
 }
 
-func (c DockerCreds) append(a DockerCreds) DockerCreds {
+func (c DockerCreds) append(a DockerCreds) (DockerCreds, error) {
 	if c == nil {
-		return a
+		return a, nil
+	} else if a == nil {
+		return c, nil
 	}
 
 	for k, v := range a {
-		c[k] = v
+		if contains, err := c.contains(k); err != nil {
+			return nil, err
+		} else if !contains {
+			c[k] = v
+		}
+	}
+
+	return c, nil
+}
+
+func (c DockerCreds) contains(reg string) (bool, error) {
+	if !strings.HasPrefix(reg, "http://") && !strings.HasPrefix(reg, "https://") {
+		reg = "//" + reg
+	}
+
+	u, err := url.Parse(reg)
+	if err != nil {
+		return false, err
 	}
-	return c
+
+	for existingRegistry := range c {
+		if (RegistryMatcher{}.Match(u.Host, existingRegistry)) {
+			return true, nil
+		}
+	}
+
+	return false, nil
 }
 
 type entry struct {

pkg/dockercreds/docker_creds_test.go

@@ -128,6 +128,34 @@ func testDockerCreds(t *testing.T, when spec.G, it spec.S) {
 
 			assert.JSONEq(t, expectedConfigJsonContents, string(configJsonBytes))
 		})
+
+		it("does not overwrite registries if they already exist in a different format", func() {
+			expectedConfigJsonContents := `{
+  "auths": {
+    "https://gcr.io": {
+      "auth": "dGVzdHVzZXJuYW1lOnRlc3RwYXNzd29yZHNpbGxpbmVzcwo=",
+      "username": "testdockerhub",
+      "password": "testdockerhubusername"
+    }
+  }
+}`
+			err := ioutil.WriteFile(filepath.Join(testPullSecretsDir, "config.json"), []byte(expectedConfigJsonContents), os.ModePerm)
+			require.NoError(t, err)
+
+			credsToAppend := DockerCreds{
+				"gcr.io": entry{
+					Auth: "newCreds=",
+				},
+			}
+
+			err = credsToAppend.AppendToDockerConfig(filepath.Join(testPullSecretsDir, "config.json"))
+			require.NoError(t, err)
+
+			configJsonBytes, err := ioutil.ReadFile(filepath.Join(testPullSecretsDir, "config.json"))
+			require.NoError(t, err)
+
+			assert.JSONEq(t, expectedConfigJsonContents, string(configJsonBytes))
+		})
 	})
 
 	when("#Resolve", func() {

pkg/dockercreds/parse_pull_secrets.go

@@ -18,7 +18,7 @@ func ParseDockerPullSecrets(path string) (DockerCreds, error) {
 		return nil, err
 	}
 
-	return dockerCfg.append(dockerJson), nil
+	return dockerCfg.append(dockerJson)
 }
 
 func parseDockerCfg(path string) (DockerCreds, error) {
@@ -44,7 +44,10 @@ func parseDockerCfg(path string) (DockerCreds, error) {
 }
 
 func parseDockerConfigJson(path string) (DockerCreds, error) {
-	var config dockerConfigJson
+	config := dockerConfigJson{
+		Auths: map[string]entry{},
+	}
+
 	configjsonExists, err := fileExists(path)
 	if err != nil {
 		return nil, err