forked from containers/build
/
manifest.go
99 lines (85 loc) · 2.31 KB
/
manifest.go
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// Copyright 2015 The appc Authors
//
// 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 util
import (
"encoding/json"
"fmt"
"io/ioutil"
"os"
"path"
"github.com/appc/spec/aci"
"github.com/appc/spec/schema"
)
// GetManifest will read in the manifest from the untarred ACI stored at acipath
func GetManifest(acipath string) (*schema.ImageManifest, error) {
acifile, err := os.Open(path.Join(acipath, aci.ManifestFile))
if err != nil {
return nil, err
}
defer acifile.Close()
manblob, err := ioutil.ReadAll(acifile)
if err != nil {
return nil, err
}
man := &schema.ImageManifest{}
err = man.UnmarshalJSON(manblob)
if err != nil {
return nil, err
}
return man, nil
}
// ModifyManifest will read in the manifest from the untarred ACI stored at
// acipath, run the fn function (which is intended to modify the manifest), and
// then write the resulting manifest back to the file it was read from.
func ModifyManifest(fn func(*schema.ImageManifest) error, acipath string) error {
man, err := GetManifest(acipath)
if err != nil {
return err
}
err = fn(man)
if err != nil {
return err
}
blob, err := man.MarshalJSON()
if err != nil {
return err
}
manfile, err := os.OpenFile(path.Join(acipath, aci.ManifestFile),
os.O_WRONLY|os.O_TRUNC, 0644)
if err != nil {
return err
}
defer manfile.Close()
_, err = manfile.Write(blob)
if err != nil {
return err
}
return nil
}
// PrintManifest will print the given manifest to stdout, optionally inserting
// whitespace to make it more human readable.
func PrintManifest(man *schema.ImageManifest, prettyPrint bool) error {
var manblob []byte
var err error
if prettyPrint {
manblob, err = json.MarshalIndent(man, "", " ")
} else {
manblob, err = man.MarshalJSON()
}
if err != nil {
return err
}
fmt.Println(string(manblob))
return nil
}