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// 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 cmd
import (
"errors"
"fmt"
"strings"
"github.com/google/go-containerregistry/pkg/crane"
"github.com/google/go-containerregistry/pkg/name"
v1 "github.com/google/go-containerregistry/pkg/v1"
"github.com/google/go-containerregistry/pkg/v1/mutate"
"github.com/spf13/cobra"
)
// NewCmdMutate creates a new cobra.Command for the mutate subcommand.
func NewCmdMutate(options *[]crane.Option) *cobra.Command {
var labels map[string]string
var annotations map[string]string
var entrypoint, cmd []string
var envVars map[string]string
var newLayers []string
var outFile string
var newRef string
var newRepo string
var user string
mutateCmd := &cobra.Command{
Use: "mutate",
Short: "Modify image labels and annotations. The container must be pushed to a registry, and the manifest is updated there.",
Args: cobra.ExactArgs(1),
RunE: func(_ *cobra.Command, args []string) error {
// Pull image and get config.
ref := args[0]
if len(annotations) != 0 {
desc, err := crane.Head(ref, *options...)
if err != nil {
return err
}
if desc.MediaType.IsIndex() {
return errors.New("mutating annotations on an index is not yet supported")
}
}
if newRepo != "" && newRef != "" {
return errors.New("repository can't be set when a tag is specified")
}
img, err := crane.Pull(ref, *options...)
if err != nil {
return fmt.Errorf("pulling %s: %w", ref, err)
}
if len(newLayers) != 0 {
img, err = crane.Append(img, newLayers...)
if err != nil {
return fmt.Errorf("appending %v: %w", newLayers, err)
}
}
cfg, err := img.ConfigFile()
if err != nil {
return err
}
cfg = cfg.DeepCopy()
// Set labels.
if cfg.Config.Labels == nil {
cfg.Config.Labels = map[string]string{}
}
if err := validateKeyVals(labels); err != nil {
return err
}
for k, v := range labels {
cfg.Config.Labels[k] = v
}
if err := validateKeyVals(annotations); err != nil {
return err
}
// set envvars if specified
if err := setEnvVars(cfg, envVars); err != nil {
return err
}
// Set entrypoint.
if len(entrypoint) > 0 {
cfg.Config.Entrypoint = entrypoint
cfg.Config.Cmd = nil // This matches Docker's behavior.
}
// Set cmd.
if len(cmd) > 0 {
cfg.Config.Cmd = cmd
}
// Set user.
if len(user) > 0 {
cfg.Config.User = user
}
// Mutate and write image.
img, err = mutate.Config(img, cfg.Config)
if err != nil {
return fmt.Errorf("mutating config: %w", err)
}
img = mutate.Annotations(img, annotations).(v1.Image)
// If the new ref isn't provided, write over the original image.
// If that ref was provided by digest (e.g., output from
// another crane command), then strip that and push the
// mutated image by digest instead.
if newRepo != "" {
newRef = newRepo
} else if newRef == "" {
newRef = ref
}
digest, err := img.Digest()
if err != nil {
return fmt.Errorf("digesting new image: %w", err)
}
if outFile != "" {
if err := crane.Save(img, newRef, outFile); err != nil {
return fmt.Errorf("writing output %q: %w", outFile, err)
}
} else {
r, err := name.ParseReference(newRef)
if err != nil {
return fmt.Errorf("parsing %s: %w", newRef, err)
}
if _, ok := r.(name.Digest); ok || newRepo != "" {
newRef = r.Context().Digest(digest.String()).String()
}
if err := crane.Push(img, newRef, *options...); err != nil {
return fmt.Errorf("pushing %s: %w", newRef, err)
}
fmt.Println(r.Context().Digest(digest.String()))
}
return nil
},
}
mutateCmd.Flags().StringToStringVarP(&annotations, "annotation", "a", nil, "New annotations to add")
mutateCmd.Flags().StringToStringVarP(&labels, "label", "l", nil, "New labels to add")
mutateCmd.Flags().StringToStringVarP(&envVars, "env", "e", nil, "New envvar to add")
mutateCmd.Flags().StringSliceVar(&entrypoint, "entrypoint", nil, "New entrypoint to set")
mutateCmd.Flags().StringSliceVar(&cmd, "cmd", nil, "New cmd to set")
mutateCmd.Flags().StringVar(&newRepo, "repo", "", "Repository to push the mutated image to. If provided, push by digest to this repository.")
mutateCmd.Flags().StringVarP(&newRef, "tag", "t", "", "New tag reference to apply to mutated image. If not provided, push by digest to the original image repository.")
mutateCmd.Flags().StringVarP(&outFile, "output", "o", "", "Path to new tarball of resulting image")
mutateCmd.Flags().StringSliceVar(&newLayers, "append", []string{}, "Path to tarball to append to image")
mutateCmd.Flags().StringVarP(&user, "user", "u", "", "New user to set")
return mutateCmd
}
// validateKeyVals ensures no values are empty, returns error if they are
func validateKeyVals(kvPairs map[string]string) error {
for label, value := range kvPairs {
if value == "" {
return fmt.Errorf("parsing label %q, value is empty", label)
}
}
return nil
}
// setEnvVars override envvars in a config
func setEnvVars(cfg *v1.ConfigFile, envVars map[string]string) error {
newEnv := make([]string, 0, len(cfg.Config.Env))
for _, old := range cfg.Config.Env {
split := strings.SplitN(old, "=", 2)
if len(split) != 2 {
return fmt.Errorf("invalid key value pair in config: %s", old)
}
// keep order so override if specified again
oldKey := split[0]
if v, ok := envVars[oldKey]; ok {
newEnv = append(newEnv, fmt.Sprintf("%s=%s", oldKey, v))
delete(envVars, oldKey)
} else {
newEnv = append(newEnv, old)
}
}
isWindows := cfg.OS == "windows"
for k, v := range envVars {
if isWindows {
k = strings.ToUpper(k)
}
newEnv = append(newEnv, fmt.Sprintf("%s=%s", k, v))
}
cfg.Config.Env = newEnv
return nil
}
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