Enable embedding of ko publish (#348)

- Export functions and a variable to enable embedding of ko's
  `publish` functionality to be embedded in other tools.

  See https://github.com/GoogleContainerTools/skaffold/pull/5611

- Remove DockerRepo PublishOption and flag.

  This removes the `DockerRepo` config option and `--docker-repo`
  flag from the PR.

  New PR with the extracted config option:
  https://github.com/google/ko/pull/351

- Fix copyright headers for boilerplate check.

- Use DockerRepo PublishOption instead of env var.

- Override defaultBaseImage using BuildOptions.

  Remove exported package global SetDefaultBaseImage and instead
  allow programmatic override of the default base image using
  the field `BaseImage` in `options.BuildOptions`.

  Also fix copyright header years.

- Add BuildOptions parameter to getBaseImage

  This enables access to BaseImage for programmatically overriding
  the default base image from `.ko.yaml`.

- Add UserAgent to BuildOptions and PublishOptions

  This enables programmatically overriding the `User-Agent` HTTP
  request header for both pulling the base image and pushing the
  built image.

- Rename MakeBuilder to NewBuilder and MakePublisher to NewPublisher.

  For more idiomatic constructor function names.

pkg/commands/config.go

@@ -1,16 +1,18 @@
-// Copyright 2018 Google LLC All Rights Reserved.
+/*
-//
+Copyright 2018 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.
+Licensed under the Apache License, Version 2.0 (the "License");
-// You may obtain a copy of the License at
+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
+
-//
+    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,
+Unless required by applicable law or agreed to in writing, software
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+distributed under the License is distributed on an "AS IS" BASIS,
-// See the License for the specific language governing permissions and
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// limitations under the License.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
 
 package commands
 
@@ -31,6 +33,7 @@ import (
 	"github.com/google/go-containerregistry/pkg/v1/remote"
 	"github.com/google/go-containerregistry/pkg/v1/types"
 	"github.com/google/ko/pkg/build"
+	"github.com/google/ko/pkg/commands/options"
 	"github.com/spf13/viper"
 )
 
@@ -39,7 +42,9 @@ var (
 	baseImageOverrides map[string]name.Reference
 )
 
-func getBaseImage(platform string) build.GetBase {
+// getBaseImage returns a function that determines the base image for a given import path.
+// If the `bo.BaseImage` parameter is non-empty, it overrides base image configuration from `.ko.yaml`.
+func getBaseImage(platform string, bo *options.BuildOptions) build.GetBase {
 	return func(ctx context.Context, s string) (build.Result, error) {
 		s = strings.TrimPrefix(s, build.StrictScheme)
 		// Viper configuration file keys are case insensitive, and are
@@ -52,9 +57,20 @@ func getBaseImage(platform string) build.GetBase {
 		if !ok {
 			ref = defaultBaseImage
 		}
+		if bo.BaseImage != "" {
+			var err error
+			ref, err = name.ParseReference(bo.BaseImage)
+			if err != nil {
+				return nil, fmt.Errorf("parsing bo.BaseImage (%q): %v", bo.BaseImage, err)
+			}
+		}
+		userAgent := ua()
+		if bo.UserAgent != "" {
+			userAgent = bo.UserAgent
+		}
 		ropt := []remote.Option{
 			remote.WithAuthFromKeychain(authn.DefaultKeychain),
-			remote.WithUserAgent(ua()),
+			remote.WithUserAgent(userAgent),
 			remote.WithContext(ctx),
 		}
 

pkg/commands/config_test.go

@@ -0,0 +1,47 @@
+/*
+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 commands
+
+import (
+	"context"
+	"testing"
+
+	"github.com/google/ko/pkg/commands/options"
+)
+
+func TestOverrideDefaultBaseImageUsingBuildOption(t *testing.T) {
+	wantDigest := "sha256:76c39a6f76890f8f8b026f89e081084bc8c64167d74e6c93da7a053cb4ccb5dd"
+	wantImage := "gcr.io/distroless/static-debian9@" + wantDigest
+	bo := &options.BuildOptions{
+		BaseImage: wantImage,
+	}
+
+	baseFn := getBaseImage("all", bo)
+	res, err := baseFn(context.Background(), "ko://example.com/helloworld")
+	if err != nil {
+		t.Fatalf("getBaseImage(): %v", err)
+	}
+
+	digest, err := res.Digest()
+	if err != nil {
+		t.Fatalf("res.Digest(): %v", err)
+	}
+	gotDigest := digest.String()
+	if gotDigest != wantDigest {
+		t.Errorf("got digest %s, wanted %s", gotDigest, wantDigest)
+	}
+}

pkg/commands/options/build.go

@@ -22,10 +22,16 @@ import (
 
 // BuildOptions represents options for the ko builder.
 type BuildOptions struct {
+	// BaseImage enables setting the default base image programmatically.
+	// If non-empty, this takes precedence over the value in `.ko.yaml`.
+	BaseImage            string
 	ConcurrentBuilds     int
 	DisableOptimizations bool
 	Platform             string
 	Labels               []string
+	// UserAgent enables overriding the default value of the `User-Agent` HTTP
+	// request header used when retrieving the base image.
+	UserAgent string
 }
 
 func AddBuildOptions(cmd *cobra.Command, bo *BuildOptions) {

pkg/commands/options/publish.go

@@ -1,5 +1,5 @@
 /*
-Copyright 2021 Google LLC All Rights Reserved.
+Copyright 2018 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.
@@ -35,6 +35,10 @@ type PublishOptions struct {
 	// LocalDomain overrides the default domain for images loaded into the local Docker daemon. Use with Local=true.
 	LocalDomain string
 
+	// UserAgent enables overriding the default value of the `User-Agent` HTTP
+	// request header used when pushing the built image to an image registry.
+	UserAgent string
+
 	Tags []string
 	// TagOnly resolves images into tag-only references.
 	TagOnly bool

pkg/commands/publisher.go

@@ -1,16 +1,18 @@
-// Copyright 2018 Google LLC All Rights Reserved.
+/*
-//
+Copyright 2018 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.
+Licensed under the Apache License, Version 2.0 (the "License");
-// You may obtain a copy of the License at
+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
+
-//
+    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,
+Unless required by applicable law or agreed to in writing, software
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+distributed under the License is distributed on an "AS IS" BASIS,
-// See the License for the specific language governing permissions and
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// limitations under the License.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
 
 package commands
 
@@ -41,6 +43,11 @@ func qualifyLocalImport(importpath string) (string, error) {
 	return pkgs[0].PkgPath, nil
 }
 
+// PublishImages publishes images
+func PublishImages(ctx context.Context, importpaths []string, pub publish.Interface, b build.Interface) (map[string]name.Reference, error) {
+	return publishImages(ctx, importpaths, pub, b)
+}
+
 func publishImages(ctx context.Context, importpaths []string, pub publish.Interface, b build.Interface) (map[string]name.Reference, error) {
 	imgs := make(map[string]name.Reference)
 	for _, importpath := range importpaths {

pkg/commands/publisher_test.go

@@ -0,0 +1,100 @@
+/*
+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 commands
+
+import (
+	"context"
+	"fmt"
+	"path/filepath"
+	"runtime"
+	"strings"
+	"testing"
+
+	"github.com/google/ko/pkg/build"
+	"github.com/google/ko/pkg/commands/options"
+)
+
+func TestPublishImages(t *testing.T) {
+	repo := "registry.example.com/repository"
+	sampleAppDir, err := sampleAppRelDir()
+	if err != nil {
+		t.Fatalf("sampleAppRelDir(): %v", err)
+	}
+	tests := []struct {
+		description string
+		publishArg  string
+		importpath  string
+	}{
+		{
+			description: "import path with ko scheme",
+			publishArg:  "ko://github.com/google/ko/test",
+			importpath:  "github.com/google/ko/test",
+		},
+		{
+			description: "import path without ko scheme",
+			publishArg:  "github.com/google/ko/test",
+			importpath:  "github.com/google/ko/test",
+		},
+		{
+			description: "file path",
+			publishArg:  sampleAppDir,
+			importpath:  "github.com/google/ko/test",
+		},
+	}
+	for _, test := range tests {
+		ctx := context.Background()
+		bo := &options.BuildOptions{
+			ConcurrentBuilds: 1,
+		}
+		builder, err := NewBuilder(ctx, bo)
+		if err != nil {
+			t.Fatalf("%s: MakeBuilder(): %v", test.description, err)
+		}
+		po := &options.PublishOptions{
+			DockerRepo:          repo,
+			PreserveImportPaths: true,
+		}
+		publisher, err := NewPublisher(po)
+		if err != nil {
+			t.Fatalf("%s: MakePublisher(): %v", test.description, err)
+		}
+		importpathWithScheme := build.StrictScheme + test.importpath
+		refs, err := PublishImages(ctx, []string{test.publishArg}, publisher, builder)
+		if err != nil {
+			t.Fatalf("%s: PublishImages(): %v", test.description, err)
+		}
+		ref, exists := refs[importpathWithScheme]
+		if !exists {
+			t.Errorf("%s: could not find image for importpath %s", test.description, importpathWithScheme)
+		}
+		gotImageName := ref.Context().Name()
+		wantImageName := strings.ToLower(fmt.Sprintf("%s/%s", repo, test.importpath))
+		if gotImageName != wantImageName {
+			t.Errorf("%s: got %s, wanted %s", test.description, gotImageName, wantImageName)
+		}
+	}
+}
+
+func sampleAppRelDir() (string, error) {
+	_, filename, _, ok := runtime.Caller(0)
+	if !ok {
+		return "", fmt.Errorf("could not get current filename")
+	}
+	basepath := filepath.Dir(filename)
+	testAppDir := filepath.Join(basepath, "..", "..", "test")
+	return filepath.Rel(basepath, testAppDir)
+}

pkg/commands/resolver.go

@@ -1,5 +1,5 @@
 /*
-Copyright 2021 Google LLC All Rights Reserved.
+Copyright 2018 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.
@@ -41,6 +41,7 @@ import (
 	"k8s.io/apimachinery/pkg/labels"
 )
 
+// ua returns the ko user agent.
 func ua() string {
 	if v := version(); v != "" {
 		return "ko/" + v
@@ -79,7 +80,7 @@ func gobuildOptions(bo *options.BuildOptions) ([]build.Option, error) {
 	}
 
 	opts := []build.Option{
-		build.WithBaseImages(getBaseImage(platform)),
+		build.WithBaseImages(getBaseImage(platform, bo)),
 		build.WithPlatforms(platform),
 	}
 	if creationTime != nil {
@@ -98,6 +99,11 @@ func gobuildOptions(bo *options.BuildOptions) ([]build.Option, error) {
 	return opts, nil
 }
 
+// NewBuilder creates a ko builder
+func NewBuilder(ctx context.Context, bo *options.BuildOptions) (build.Interface, error) {
+	return makeBuilder(ctx, bo)
+}
+
 func makeBuilder(ctx context.Context, bo *options.BuildOptions) (*build.Caching, error) {
 	opt, err := gobuildOptions(bo)
 	if err != nil {
@@ -129,6 +135,11 @@ func makeBuilder(ctx context.Context, bo *options.BuildOptions) (*build.Caching,
 	return build.NewCaching(innerBuilder)
 }
 
+// NewPublisher creates a ko publisher
+func NewPublisher(po *options.PublishOptions) (publish.Interface, error) {
+	return makePublisher(po)
+}
+
 func makePublisher(po *options.PublishOptions) (publish.Interface, error) {
 	// Create the publish.Interface that we will use to publish image references
 	// to either a docker daemon or a container image registry.
@@ -151,7 +162,7 @@ func makePublisher(po *options.PublishOptions) (publish.Interface, error) {
 		}
 		if _, err := name.NewRegistry(repoName); err != nil {
 			if _, err := name.NewRepository(repoName); err != nil {
-				return nil, fmt.Errorf("failed to parse environment variable KO_DOCKER_REPO=%q as repository: %v", repoName, err)
+				return nil, fmt.Errorf("failed to parse %q as repository: %v", repoName, err)
 			}
 		}
 
@@ -167,9 +178,13 @@ func makePublisher(po *options.PublishOptions) (publish.Interface, error) {
 			tp := publish.NewTarball(po.TarballFile, repoName, namer, po.Tags)
 			publishers = append(publishers, tp)
 		}
+		userAgent := ua()
+		if po.UserAgent != "" {
+			userAgent = po.UserAgent
+		}
 		if po.Push {
 			dp, err := publish.NewDefault(repoName,
-				publish.WithUserAgent(ua()),
+				publish.WithUserAgent(userAgent),
 				publish.WithAuthFromKeychain(authn.DefaultKeychain),
 				publish.WithNamer(namer),
 				publish.WithTags(po.Tags),
@@ -208,6 +223,7 @@ type nopPublisher struct {
 }
 
 func (n nopPublisher) Publish(_ context.Context, br build.Result, s string) (name.Reference, error) {
+	s = strings.TrimPrefix(s, build.StrictScheme)
 	h, err := br.Digest()
 	if err != nil {
 		return nil, err

pkg/commands/resolver_test.go

@@ -1,16 +1,18 @@
-// Copyright 2018 Google LLC All Rights Reserved.
+/*
-//
+Copyright 2018 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.
+Licensed under the Apache License, Version 2.0 (the "License");
-// You may obtain a copy of the License at
+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
+
-//
+    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,
+Unless required by applicable law or agreed to in writing, software
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+distributed under the License is distributed on an "AS IS" BASIS,
-// See the License for the specific language governing permissions and
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// limitations under the License.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
 
 package commands
 
@@ -20,12 +22,14 @@ import (
 	"fmt"
 	"io"
 	"io/ioutil"
+	"strings"
 	"testing"
 
 	"github.com/google/go-cmp/cmp"
 	"github.com/google/go-cmp/cmp/cmpopts"
 	"github.com/google/go-containerregistry/pkg/name"
 	v1 "github.com/google/go-containerregistry/pkg/v1"
+	"github.com/google/go-containerregistry/pkg/v1/empty"
 	"github.com/google/go-containerregistry/pkg/v1/random"
 	"github.com/google/ko/pkg/build"
 	"github.com/google/ko/pkg/commands/options"
@@ -134,6 +138,52 @@ kind: Bar
 	}
 }
 
+func TestMakeBuilder(t *testing.T) {
+	ctx := context.Background()
+	bo := &options.BuildOptions{
+		ConcurrentBuilds: 1,
+	}
+	builder, err := NewBuilder(ctx, bo)
+	if err != nil {
+		t.Fatalf("MakeBuilder(): %v", err)
+	}
+	res, err := builder.Build(ctx, "ko://github.com/google/ko/test")
+	if err != nil {
+		t.Fatalf("builder.Build(): %v", err)
+	}
+	gotDigest, err := res.Digest()
+	if err != nil {
+		t.Fatalf("res.Digest(): %v", err)
+	}
+	fmt.Println(gotDigest.String())
+}
+
+func TestMakePublisher(t *testing.T) {
+	repo := "registry.example.com/repository"
+	po := &options.PublishOptions{
+		DockerRepo:          repo,
+		PreserveImportPaths: true,
+	}
+	publisher, err := NewPublisher(po)
+	if err != nil {
+		t.Fatalf("MakePublisher(): %v", err)
+	}
+	defer publisher.Close()
+	ctx := context.Background()
+	importpath := "github.com/google/ko/test"
+	importpathWithScheme := build.StrictScheme + importpath
+	buildResult := empty.Index
+	ref, err := publisher.Publish(ctx, buildResult, importpathWithScheme)
+	if err != nil {
+		t.Fatalf("publisher.Publish(): %v", err)
+	}
+	gotImageName := ref.Context().Name()
+	wantImageName := strings.ToLower(fmt.Sprintf("%s/%s", repo, importpath))
+	if gotImageName != wantImageName {
+		t.Errorf("got %s, wanted %s", gotImageName, wantImageName)
+	}
+}
+
 func mustRepository(s string) name.Repository {
 	n, err := name.NewRepository(s)
 	if err != nil {