prometheus/cmd/promtool/archive.go

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// Copyright 2015 The Prometheus 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 main
import (
"archive/tar"
"compress/gzip"
"fmt"
"os"
)
const filePerm = 0644
type archiver interface {
write(filename string, b []byte) error
close() error
filename() string
}
type tarGzFileWriter struct {
tarWriter *tar.Writer
gzWriter *gzip.Writer
file *os.File
}
func newTarGzFileWriter(archiveName string) (*tarGzFileWriter, error) {
file, err := os.Create(archiveName)
if err != nil {
return nil, fmt.Errorf("error creating archive %q: %s", archiveName, err)
}
gzw := gzip.NewWriter(file)
tw := tar.NewWriter(gzw)
return &tarGzFileWriter{
tarWriter: tw,
gzWriter: gzw,
file: file,
}, nil
}
func (w *tarGzFileWriter) close() error {
if err := w.tarWriter.Close(); err != nil {
return err
}
if err := w.gzWriter.Close(); err != nil {
return err
}
return w.file.Close()
}
func (w *tarGzFileWriter) write(filename string, b []byte) error {
header := &tar.Header{
Name: filename,
Mode: filePerm,
Size: int64(len(b)),
}
if err := w.tarWriter.WriteHeader(header); err != nil {
return err
}
if _, err := w.tarWriter.Write(b); err != nil {
return err
}
return nil
}
func (w *tarGzFileWriter) filename() string {
return w.file.Name()
}