Allow to customize publish.Namer (ko-build#477)

* Allow to customize publish.Namer

Fixes ko-build#476

* Removing a CLI flag for path separator

* Removing ImageNameSeparator option after review

pkg/commands/options/namer_test.go

@@ -0,0 +1,72 @@
+// Copyright 2021 Google LLC All Rights Reserved.
+//
+// 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 options_test
+
+import (
+	"path"
+	"testing"
+
+	"github.com/google/ko/pkg/commands/options"
+)
+
+func TestMakeNamer(t *testing.T) {
+	foreachTestCaseMakeNamer(func(tc testMakeNamerCase) {
+		t.Run(tc.name, func(t *testing.T) {
+			namer := options.MakeNamer(&tc.opts)
+			got := namer("registry.example.org/foo/bar", "example.org/sample/cmd/example")
+
+			if got != tc.want {
+				t.Errorf("got image name %s, wanted %s", got, tc.want)
+			}
+		})
+	})
+}
+
+func foreachTestCaseMakeNamer(fn func(tc testMakeNamerCase)) {
+	for _, namerCase := range testMakeNamerCases() {
+		fn(namerCase)
+	}
+}
+
+func testMakeNamerCases() []testMakeNamerCase {
+	return []testMakeNamerCase{{
+		name: "defaults",
+		want: "registry.example.org/foo/bar/example-51d74b7127c5f7495a338df33ecdeb19",
+	}, {
+		name: "with preserve import paths",
+		want: "registry.example.org/foo/bar/example.org/sample/cmd/example",
+		opts: options.PublishOptions{PreserveImportPaths: true},
+	}, {
+		name: "with base import paths",
+		want: "registry.example.org/foo/bar/example",
+		opts: options.PublishOptions{BaseImportPaths: true},
+	}, {
+		name: "with bare",
+		want: "registry.example.org/foo/bar",
+		opts: options.PublishOptions{Bare: true},
+	}, {
+		name: "with custom namer",
+		want: "registry.example.org/foo/bar-example",
+		opts: options.PublishOptions{ImageNamer: func(base string, importpath string) string {
+			return base + "-" + path.Base(importpath)
+		}},
+	}}
+}
+
+type testMakeNamerCase struct {
+	name string
+	opts options.PublishOptions
+	want string
+}

pkg/commands/options/publish.go

@@ -17,7 +17,7 @@ limitations under the License.
 package options
 
 import (
-	"crypto/md5" //nolint: gosec // No strong cryptography needed.
+	"crypto/md5" // nolint: gosec // No strong cryptography needed.
 	"encoding/hex"
 	"os"
 	"path"
@@ -65,6 +65,9 @@ type PublishOptions struct {
 	BaseImportPaths bool
 	// Bare uses a tag on the KO_DOCKER_REPO without anything additional.
 	Bare bool
+	// ImageNamer can be used to pass a custom image name function. When given
+	// PreserveImportPaths, BaseImportPaths, Bare has no effect.
+	ImageNamer publish.Namer
 }
 
 func AddPublishArg(cmd *cobra.Command, po *PublishOptions) {
@@ -99,7 +102,7 @@ func AddPublishArg(cmd *cobra.Command, po *PublishOptions) {
 }
 
 func packageWithMD5(base, importpath string) string {
-	hasher := md5.New() //nolint: gosec // No strong cryptography needed.
+	hasher := md5.New() // nolint: gosec // No strong cryptography needed.
 	hasher.Write([]byte(importpath))
 	return path.Join(base, path.Base(importpath)+"-"+hex.EncodeToString(hasher.Sum(nil)))
 }
@@ -117,7 +120,9 @@ func bareDockerRepo(base, _ string) string {
 }
 
 func MakeNamer(po *PublishOptions) publish.Namer {
-	if po.PreserveImportPaths {
+	if po.ImageNamer != nil {
+		return po.ImageNamer
+	} else if po.PreserveImportPaths {
 		return preserveImportPath
 	} else if po.BaseImportPaths {
 		return baseImportPaths