1 files changed, 122 insertions, 0 deletions
diff --git a/pkg/gcrane/options.go b/pkg/gcrane/options.go
new file mode 100644
index 0000000..9d34c7d
--- /dev/null
+++ b/pkg/gcrane/options.go
@@ -0,0 +1,122 @@
+// Copyright 2019 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 gcrane
+
+import (
+	"context"
+	"net/http"
+	"runtime"
+
+	"github.com/google/go-containerregistry/pkg/authn"
+	"github.com/google/go-containerregistry/pkg/crane"
+	"github.com/google/go-containerregistry/pkg/v1/google"
+	"github.com/google/go-containerregistry/pkg/v1/remote"
+)
+
+// Option is a functional option for gcrane operations.
+type Option func(*options)
+
+type options struct {
+	jobs   int
+	remote []remote.Option
+	google []google.Option
+	crane  []crane.Option
+}
+
+func makeOptions(opts ...Option) *options {
+	o := &options{
+		jobs: runtime.GOMAXPROCS(0),
+		remote: []remote.Option{
+			remote.WithAuthFromKeychain(Keychain),
+		},
+		google: []google.Option{
+			google.WithAuthFromKeychain(Keychain),
+		},
+		crane: []crane.Option{
+			crane.WithAuthFromKeychain(Keychain),
+		},
+	}
+
+	for _, option := range opts {
+		option(o)
+	}
+
+	return o
+}
+
+// WithJobs sets the number of concurrent jobs to run.
+//
+// The default number of jobs is GOMAXPROCS.
+func WithJobs(jobs int) Option {
+	return func(o *options) {
+		o.jobs = jobs
+	}
+}
+
+// WithTransport is a functional option for overriding the default transport
+// for remote operations.
+func WithTransport(t http.RoundTripper) Option {
+	return func(o *options) {
+		o.remote = append(o.remote, remote.WithTransport(t))
+		o.google = append(o.google, google.WithTransport(t))
+		o.crane = append(o.crane, crane.WithTransport(t))
+	}
+}
+
+// WithUserAgent adds the given string to the User-Agent header for any HTTP
+// requests.
+func WithUserAgent(ua string) Option {
+	return func(o *options) {
+		o.remote = append(o.remote, remote.WithUserAgent(ua))
+		o.google = append(o.google, google.WithUserAgent(ua))
+		o.crane = append(o.crane, crane.WithUserAgent(ua))
+	}
+}
+
+// WithContext is a functional option for setting the context.
+func WithContext(ctx context.Context) Option {
+	return func(o *options) {
+		o.remote = append(o.remote, remote.WithContext(ctx))
+		o.google = append(o.google, google.WithContext(ctx))
+		o.crane = append(o.crane, crane.WithContext(ctx))
+	}
+}
+
+// WithKeychain is a functional option for overriding the default
+// authenticator for remote operations, using an authn.Keychain to find
+// credentials.
+//
+// By default, gcrane will use gcrane.Keychain.
+func WithKeychain(keys authn.Keychain) Option {
+	return func(o *options) {
+		// Replace the default keychain at position 0.
+		o.remote[0] = remote.WithAuthFromKeychain(keys)
+		o.google[0] = google.WithAuthFromKeychain(keys)
+		o.crane[0] = crane.WithAuthFromKeychain(keys)
+	}
+}
+
+// WithAuth is a functional option for overriding the default authenticator
+// for remote operations.
+//
+// By default, gcrane will use gcrane.Keychain.
+func WithAuth(auth authn.Authenticator) Option {
+	return func(o *options) {
+		// Replace the default keychain at position 0.
+		o.remote[0] = remote.WithAuth(auth)
+		o.google[0] = google.WithAuth(auth)
+		o.crane[0] = crane.WithAuth(auth)
+	}
+}