Auto configure authentication helper for gcr.io

Fixes #966

Signed-off-by: David Gageot <david@gageot.net>

pkg/skaffold/docker/auth.go

@@ -23,6 +23,7 @@ import (
 	"os"
 	"path/filepath"
 
+	"github.com/GoogleContainerTools/skaffold/pkg/skaffold/gcp"
 	"github.com/docker/cli/cli/config"
 	"github.com/docker/distribution/reference"
 	"github.com/docker/docker/api/types"
@@ -64,6 +65,9 @@ func (credsHelper) GetAuthConfig(registry string) (types.AuthConfig, error) {
 	if err != nil {
 		return types.AuthConfig{}, errors.Wrap(err, "docker config")
 	}
+
+	gcp.AutoConfigureGCRCredentialHelper(cf, registry)
+
 	return cf.GetAuthConfig(registry)
 }
 

pkg/skaffold/gcp/auth.go

@@ -0,0 +1,49 @@
+/*
+Copyright 2018 The Skaffold Authors
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package gcp
+
+import (
+	"os/exec"
+	"strings"
+
+	"github.com/docker/cli/cli/config/configfile"
+	"github.com/sirupsen/logrus"
+)
+
+// AutoConfigureGCRCredentialHelper automatically adds the `gcloud` credential helper
+// to docker's configuration.
+// This doesn't modify the ~/.docker/config.json. It's only in-memory
+func AutoConfigureGCRCredentialHelper(cf *configfile.ConfigFile, registry string) {
+	if registry != "gcr.io" && !strings.HasSuffix(registry, ".gcr.io") {
+		return
+	}
+
+	if cf.CredentialHelpers != nil && cf.CredentialHelpers[registry] != "" {
+		return
+	}
+
+	if path, _ := exec.LookPath("docker-credential-gcloud"); path == "" {
+		return
+	}
+
+	logrus.Debugf("Adding `gcloud` as a docker credential helper for [%s]", registry)
+
+	if cf.CredentialHelpers == nil {
+		cf.CredentialHelpers = make(map[string]string)
+	}
+	cf.CredentialHelpers[registry] = "gcloud"
+}

pkg/skaffold/gcp/auth_test.go

@@ -0,0 +1,117 @@
+/*
+Copyright 2018 The Skaffold Authors
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package gcp
+
+import (
+	"testing"
+
+	"github.com/GoogleContainerTools/skaffold/testutil"
+	"github.com/docker/cli/cli/config/configfile"
+)
+
+func TestAutoConfigureGCRCredentialHelper(t *testing.T) {
+	var tests = []struct {
+		description  string
+		registry     string
+		helperInPath bool
+		config       *configfile.ConfigFile
+		expected     *configfile.ConfigFile
+	}{
+		{
+			description:  "add to nil map",
+			registry:     "gcr.io",
+			helperInPath: true,
+			config:       &configfile.ConfigFile{},
+			expected: &configfile.ConfigFile{
+				CredentialHelpers: map[string]string{
+					"gcr.io": "gcloud",
+				},
+			},
+		},
+		{
+			description:  "add to empty map",
+			registry:     "gcr.io",
+			helperInPath: true,
+			config: &configfile.ConfigFile{
+				CredentialHelpers: map[string]string{},
+			},
+			expected: &configfile.ConfigFile{
+				CredentialHelpers: map[string]string{
+					"gcr.io": "gcloud",
+				},
+			},
+		},
+		{
+			description: "leave existing helper",
+			registry:    "gcr.io",
+			config: &configfile.ConfigFile{
+				CredentialHelpers: map[string]string{
+					"gcr.io": "existing",
+				},
+			},
+			expected: &configfile.ConfigFile{
+				CredentialHelpers: map[string]string{
+					"gcr.io": "existing",
+				},
+			},
+		},
+		{
+			description:  "any.gcr.io",
+			registry:     "any.gcr.io",
+			helperInPath: true,
+			config:       &configfile.ConfigFile{},
+			expected: &configfile.ConfigFile{
+				CredentialHelpers: map[string]string{
+					"any.gcr.io": "gcloud",
+				},
+			},
+		},
+		{
+			description:  "case is important",
+			registry:     "GCR.io",
+			helperInPath: true,
+			config:       &configfile.ConfigFile{},
+			expected:     &configfile.ConfigFile{},
+		},
+		{
+			description:  "ignore if gcloud is not in PATH",
+			registry:     "gcr.io",
+			helperInPath: false,
+			config:       &configfile.ConfigFile{},
+			expected:     &configfile.ConfigFile{},
+		},
+	}
+	for _, test := range tests {
+		t.Run(test.description, func(t *testing.T) {
+			tmp, cleanup := testutil.NewTempDir(t)
+			defer cleanup()
+
+			reset := testutil.SetEnvs(t, map[string]string{
+				"PATH": tmp.Root(),
+			})
+			defer reset(t)
+
+			if test.helperInPath {
+				tmp.Write("docker-credential-gcloud", "")
+			}
+
+			AutoConfigureGCRCredentialHelper(test.config, test.registry)
+
+			testutil.CheckDeepEqual(t, test.expected, test.config)
+		})
+	}
+}