Introduce support for pull-policy in v1alpha3

Signed-off-by: Simon Ferquel <simon.ferquel@docker.com>

cli/command/stack/kubernetes/convert.go

@@ -22,6 +22,8 @@ import (
 const (
 	// PullSecretExtraField is an extra field on ServiceConfigs usable to reference a pull secret
 	PullSecretExtraField = "x-pull-secret"
+	// PullPolicyExtraField is an extra field on ServiceConfigs usable to explicitly set the service's pull policy
+	PullPolicyExtraField = "x-pull-policy"
 )
 
 // NewStackConverter returns a converter from types.Config (compose) to the specified
@@ -242,15 +244,18 @@ func fromComposeConfigs(s map[string]composeTypes.ConfigObjConfig) map[string]la
 }
 
 func fromComposeServiceConfig(s composeTypes.ServiceConfig, caps composeCapabilities) (latest.ServiceConfig, error) {
-	var userID *int64
+	var (
+		userID     *int64
+		pullSecret string
+		pullPolicy string
+	)
 	if s.User != "" {
 		numerical, err := strconv.Atoi(s.User)
 		if err == nil {
 			unixUserID := int64(numerical)
 			userID = &unixUserID
 		}
 	}
-	var pullSecret string
 	if psInterface, ok := s.Extras[PullSecretExtraField]; ok {
 		if !caps.hasPullSecrets {
 			return latest.ServiceConfig{}, errors.Errorf("stack API version %s does not support pull secrets, please use version v1alpha3", caps.apiVersion)
@@ -259,6 +264,14 @@ func fromComposeServiceConfig(s composeTypes.ServiceConfig, caps composeCapabili
 			return latest.ServiceConfig{}, errors.Errorf("pull secret %v type is %T, should be a string", psInterface, psInterface)
 		}
 	}
+	if ppInterface, ok := s.Extras[PullPolicyExtraField]; ok {
+		if !caps.hasPullPolicy {
+			return latest.ServiceConfig{}, errors.Errorf("stack API version %s does not support pull policies, please use version v1alpha3", caps.apiVersion)
+		}
+		if pullPolicy, ok = ppInterface.(string); !ok {
+			return latest.ServiceConfig{}, errors.Errorf("pull secret %v type is %T, should be a string", ppInterface, ppInterface)
+		}
+	}
 	return latest.ServiceConfig{
 		Name:    s.Name,
 		CapAdd:  s.CapAdd,
@@ -295,6 +308,7 @@ func fromComposeServiceConfig(s composeTypes.ServiceConfig, caps composeCapabili
 		Volumes:         fromComposeServiceVolumeConfig(s.Volumes),
 		WorkingDir:      s.WorkingDir,
 		PullSecret:      pullSecret,
+		PullPolicy:      pullPolicy,
 	}, nil
 }
 
@@ -467,10 +481,12 @@ var (
 	v1alpha3Capabilities = composeCapabilities{
 		apiVersion:     "v1alpha3",
 		hasPullSecrets: true,
+		hasPullPolicy:  true,
 	}
 )
 
 type composeCapabilities struct {
 	apiVersion     string
 	hasPullSecrets bool
+	hasPullPolicy  bool
 }

cli/command/stack/kubernetes/convert_test.go

@@ -63,3 +63,45 @@ func TestHandlePullSecret(t *testing.T) {
 		})
 	}
 }
+
+func loadTestStackWithPullPolicy(t *testing.T) *composetypes.Config {
+	t.Helper()
+	data, err := ioutil.ReadFile("testdata/compose-with-pull-policy.yml")
+	assert.NilError(t, err)
+	yamlData, err := loader.ParseYAML(data)
+	assert.NilError(t, err)
+	cfg, err := loader.Load(composetypes.ConfigDetails{
+		ConfigFiles: []composetypes.ConfigFile{
+			{Config: yamlData, Filename: "testdata/compose-with-pull-policy.yml"},
+		},
+	})
+	assert.NilError(t, err)
+	return cfg
+}
+
+func TestHandlePullPolicy(t *testing.T) {
+	testData := loadTestStackWithPullPolicy(t)
+	cases := []struct {
+		version string
+		err     string
+	}{
+		{version: "v1beta1", err: "stack API version v1beta1 does not support pull policies, please use version v1alpha3"},
+		{version: "v1beta2", err: "stack API version v1beta2 does not support pull policies, please use version v1alpha3"},
+		{version: "v1alpha3"},
+	}
+
+	for _, c := range cases {
+		t.Run(c.version, func(t *testing.T) {
+			conv, err := NewStackConverter(c.version)
+			assert.NilError(t, err)
+			s, err := conv.FromCompose(ioutil.Discard, "test", testData)
+			if c.err != "" {
+				assert.Error(t, err, c.err)
+
+			} else {
+				assert.NilError(t, err)
+				assert.Equal(t, s.Spec.Services[0].PullPolicy, "Never")
+			}
+		})
+	}
+}

cli/command/stack/kubernetes/testdata/compose-with-pull-policy.yml

@@ -0,0 +1,5 @@
+version: "3.7"
+services:
+  test:
+    image: "some-image"
+    x-pull-policy: "Never"