kubernetes/pkg/credentialprovider/gcp/jwt.go
Matt Moore d5e0054eb0 Enable usage of a "json key" for authenticating with gcr.io.
With this change, you can add --google_json_key=/path/to/key.json to the DAEMON_ARGS of the kubelet, e.g.
   nano /etc/default/kubelet
   ... # Add the flag
   service kubelet restart

With this setting, minions will be able to authenticate with gcr.io repositories nearly as smoothly as if K8s were running on GCE.

NOTE: This private key can be used to access most project resources, consider dropping the service account created through this flow to a project READER, or restricting its access to just the GCS bucket containing the container images.
2015-03-15 09:24:33 -07:00

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Go

/*
Copyright 2014 Google Inc. 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 gcp_credentials
import (
"io/ioutil"
"time"
"github.com/GoogleCloudPlatform/kubernetes/pkg/credentialprovider"
"github.com/golang/glog"
"golang.org/x/oauth2"
"golang.org/x/oauth2/google"
"golang.org/x/oauth2/jwt"
"github.com/spf13/pflag"
)
const (
storageReadOnlyScope = "https://www.googleapis.com/auth/devstorage.read_only"
)
var (
flagJwtFile = pflag.String("google_json_key", "",
"The Google Cloud Platform Service Account JSON Key to use for authentication.")
)
// A DockerConfigProvider that reads its configuration from Google
// Compute Engine metadata.
type jwtProvider struct {
path *string
config *jwt.Config
tokenUrl string
}
// init registers the various means by which credentials may
// be resolved on GCP.
func init() {
credentialprovider.RegisterCredentialProvider("google-jwt-key",
&credentialprovider.CachingDockerConfigProvider{
Provider: &jwtProvider{
path: flagJwtFile,
},
Lifetime: 30 * time.Minute,
})
}
// Enabled implements DockerConfigProvider for the JSON Key based implementation.
func (j *jwtProvider) Enabled() bool {
if *j.path == "" {
return false
}
data, err := ioutil.ReadFile(*j.path)
if err != nil {
glog.Errorf("while reading file %s got %v", *j.path, err)
return false
}
config, err := google.JWTConfigFromJSON(data, storageReadOnlyScope)
if err != nil {
glog.Errorf("while parsing %s data got %v", *j.path, err)
return false
}
j.config = config
if j.tokenUrl != "" {
j.config.TokenURL = j.tokenUrl
}
return true
}
// Provide implements DockerConfigProvider
func (j *jwtProvider) Provide() credentialprovider.DockerConfig {
cfg := credentialprovider.DockerConfig{}
ts := j.config.TokenSource(oauth2.NoContext)
token, err := ts.Token()
if err != nil {
glog.Errorf("while exchanging json key %s for access token %v", *j.path, err)
return cfg
}
if !token.Valid() {
glog.Errorf("Got back invalid token: %v", token)
return cfg
}
entry := credentialprovider.DockerConfigEntry{
Username: "_token",
Password: token.AccessToken,
Email: j.config.Email,
}
// Add our entry for each of the supported container registry URLs
for _, k := range containerRegistryUrls {
cfg[k] = entry
}
return cfg
}