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restic/vendor/github.com/kurin/blazer/examples/simple/simple.go
2017-07-23 14:25:38 +02:00

134 lines
2.9 KiB
Go

// Copyright 2017, Google
//
// 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.
// This is a simple program that will copy named files into or out of B2.
//
// To copy a file into B2:
//
// B2_ACCOUNT_ID=foo B2_ACCOUNT_KEY=bar simple /path/to/file b2://bucket/path/to/dst
//
// To copy a file out:
//
// B2_ACCOUNT_ID=foo B2_ACCOUNT_KEY=bar simple b2://bucket/path/to/file /path/to/dst
package main
import (
"context"
"flag"
"fmt"
"io"
"net/url"
"os"
"strings"
"github.com/kurin/blazer/b2"
)
func main() {
flag.Parse()
b2id := os.Getenv("B2_ACCOUNT_ID")
b2key := os.Getenv("B2_ACCOUNT_KEY")
args := flag.Args()
if len(args) != 2 {
fmt.Printf("Usage:\n\nsimple [src] [dst]\n")
return
}
src, dst := args[0], args[1]
ctx := context.Background()
c, err := b2.NewClient(ctx, b2id, b2key)
if err != nil {
fmt.Println(err)
return
}
var r io.ReadCloser
var w io.WriteCloser
if strings.HasPrefix(src, "b2://") {
reader, err := b2Reader(ctx, c, src)
if err != nil {
fmt.Println(err)
return
}
r = reader
} else {
f, err := os.Open(src)
if err != nil {
fmt.Println(err)
return
}
r = f
}
// Readers do not need their errors checked on close. (Also it's a little
// silly to defer this in main(), but.)
defer r.Close()
if strings.HasPrefix(dst, "b2://") {
writer, err := b2Writer(ctx, c, dst)
if err != nil {
fmt.Println(err)
return
}
w = writer
} else {
f, err := os.Create(dst)
if err != nil {
fmt.Println(err)
return
}
w = f
}
// Copy and check error.
if _, err := io.Copy(w, r); err != nil {
fmt.Println(err)
return
}
// It is very important to check the error of the writer.
if err := w.Close(); err != nil {
fmt.Println(err)
}
}
func b2Reader(ctx context.Context, c *b2.Client, path string) (io.ReadCloser, error) {
o, err := b2Obj(ctx, c, path)
if err != nil {
return nil, err
}
return o.NewReader(ctx), nil
}
func b2Writer(ctx context.Context, c *b2.Client, path string) (io.WriteCloser, error) {
o, err := b2Obj(ctx, c, path)
if err != nil {
return nil, err
}
return o.NewWriter(ctx), nil
}
func b2Obj(ctx context.Context, c *b2.Client, path string) (*b2.Object, error) {
uri, err := url.Parse(path)
if err != nil {
return nil, err
}
bucket, err := c.Bucket(ctx, uri.Host)
if err != nil {
return nil, err
}
// B2 paths must not begin with /, so trim it here.
return bucket.Object(strings.TrimPrefix(uri.Path, "/")), nil
}