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// 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.
// 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 crane
import (
"archive/tar"
"bytes"
"io"
"sort"
v1 "github.com/google/go-containerregistry/pkg/v1"
"github.com/google/go-containerregistry/pkg/v1/empty"
"github.com/google/go-containerregistry/pkg/v1/mutate"
"github.com/google/go-containerregistry/pkg/v1/tarball"
)
// Layer creates a layer from a single file map. These layers are reproducible and consistent.
// A filemap is a path -> file content map representing a file system.
func Layer(filemap map[string][]byte) (v1.Layer, error) {
b := &bytes.Buffer{}
w := tar.NewWriter(b)
fn := []string{}
for f := range filemap {
fn = append(fn, f)
}
sort.Strings(fn)
for _, f := range fn {
c := filemap[f]
if err := w.WriteHeader(&tar.Header{
Name: f,
Size: int64(len(c)),
}); err != nil {
return nil, err
}
if _, err := w.Write(c); err != nil {
return nil, err
}
}
if err := w.Close(); err != nil {
return nil, err
}
// Return a new copy of the buffer each time it's opened.
return tarball.LayerFromOpener(func() (io.ReadCloser, error) {
return io.NopCloser(bytes.NewBuffer(b.Bytes())), nil
})
}
// Image creates a image with the given filemaps as its contents. These images are reproducible and consistent.
// A filemap is a path -> file content map representing a file system.
func Image(filemap map[string][]byte) (v1.Image, error) {
y, err := Layer(filemap)
if err != nil {
return nil, err
}
return mutate.AppendLayers(empty.Image, y)
}
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