433 lines
12 KiB
Go
433 lines
12 KiB
Go
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// Copyright 2014 Google Inc. All Rights Reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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// Package main is an example Mananged VM app using the Google Cloud Storage API.
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package main
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//[START imports]
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import (
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"bytes"
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"fmt"
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"io"
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"io/ioutil"
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"net/http"
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"strings"
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"cloud.google.com/go/storage"
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"golang.org/x/net/context"
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"google.golang.org/api/iterator"
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"google.golang.org/appengine"
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"google.golang.org/appengine/file"
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"google.golang.org/appengine/log"
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)
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//[END imports]
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func main() {
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http.HandleFunc("/", handler)
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appengine.Main()
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}
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//[START bucket_struct]
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// demo struct holds information needed to run the various demo functions.
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type demo struct {
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client *storage.Client
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bucketName string
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bucket *storage.BucketHandle
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w io.Writer
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ctx context.Context
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// cleanUp is a list of filenames that need cleaning up at the end of the demo.
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cleanUp []string
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// failed indicates that one or more of the demo steps failed.
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failed bool
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}
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//[END bucket_struct]
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func (d *demo) errorf(format string, args ...interface{}) {
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d.failed = true
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fmt.Fprintln(d.w, fmt.Sprintf(format, args...))
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log.Errorf(d.ctx, format, args...)
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}
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// handler is the main demo entry point that calls the GCS operations.
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func handler(w http.ResponseWriter, r *http.Request) {
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ctx := appengine.NewContext(r)
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if r.URL.Path != "/" {
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http.NotFound(w, r)
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return
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}
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//[START get_default_bucket]
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// Use `dev_appserver.py --default_gcs_bucket_name GCS_BUCKET_NAME`
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// when running locally.
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bucket, err := file.DefaultBucketName(ctx)
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if err != nil {
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log.Errorf(ctx, "failed to get default GCS bucket name: %v", err)
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}
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//[END get_default_bucket]
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client, err := storage.NewClient(ctx)
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if err != nil {
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log.Errorf(ctx, "failed to create client: %v", err)
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return
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}
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defer client.Close()
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w.Header().Set("Content-Type", "text/plain; charset=utf-8")
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fmt.Fprintf(w, "Demo GCS Application running from Version: %v\n", appengine.VersionID(ctx))
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fmt.Fprintf(w, "Using bucket name: %v\n\n", bucket)
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buf := &bytes.Buffer{}
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d := &demo{
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w: buf,
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ctx: ctx,
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client: client,
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bucket: client.Bucket(bucket),
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bucketName: bucket,
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}
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n := "demo-testfile-go"
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d.createFile(n)
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d.readFile(n)
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d.copyFile(n)
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d.statFile(n)
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d.createListFiles()
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d.listBucket()
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d.listBucketDirMode()
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d.defaultACL()
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d.putDefaultACLRule()
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d.deleteDefaultACLRule()
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d.bucketACL()
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d.putBucketACLRule()
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d.deleteBucketACLRule()
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d.acl(n)
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d.putACLRule(n)
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d.deleteACLRule(n)
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d.deleteFiles()
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if d.failed {
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w.WriteHeader(http.StatusInternalServerError)
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buf.WriteTo(w)
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fmt.Fprintf(w, "\nDemo failed.\n")
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} else {
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w.WriteHeader(http.StatusOK)
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buf.WriteTo(w)
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fmt.Fprintf(w, "\nDemo succeeded.\n")
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}
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}
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//[START write]
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// createFile creates a file in Google Cloud Storage.
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func (d *demo) createFile(fileName string) {
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fmt.Fprintf(d.w, "Creating file /%v/%v\n", d.bucket, fileName)
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wc := d.bucket.Object(fileName).NewWriter(d.ctx)
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wc.ContentType = "text/plain"
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wc.Metadata = map[string]string{
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"x-goog-meta-foo": "foo",
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"x-goog-meta-bar": "bar",
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}
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d.cleanUp = append(d.cleanUp, fileName)
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if _, err := wc.Write([]byte("abcde\n")); err != nil {
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d.errorf("createFile: unable to write data to bucket %q, file %q: %v", d.bucketName, fileName, err)
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return
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}
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if _, err := wc.Write([]byte(strings.Repeat("f", 1024*4) + "\n")); err != nil {
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d.errorf("createFile: unable to write data to bucket %q, file %q: %v", d.bucketName, fileName, err)
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return
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}
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if err := wc.Close(); err != nil {
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d.errorf("createFile: unable to close bucket %q, file %q: %v", d.bucketName, fileName, err)
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return
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}
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}
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//[END write]
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//[START read]
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// readFile reads the named file in Google Cloud Storage.
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func (d *demo) readFile(fileName string) {
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io.WriteString(d.w, "\nAbbreviated file content (first line and last 1K):\n")
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rc, err := d.bucket.Object(fileName).NewReader(d.ctx)
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if err != nil {
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d.errorf("readFile: unable to open file from bucket %q, file %q: %v", d.bucketName, fileName, err)
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return
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}
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defer rc.Close()
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slurp, err := ioutil.ReadAll(rc)
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if err != nil {
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d.errorf("readFile: unable to read data from bucket %q, file %q: %v", d.bucketName, fileName, err)
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return
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}
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fmt.Fprintf(d.w, "%s\n", bytes.SplitN(slurp, []byte("\n"), 2)[0])
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if len(slurp) > 1024 {
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fmt.Fprintf(d.w, "...%s\n", slurp[len(slurp)-1024:])
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} else {
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fmt.Fprintf(d.w, "%s\n", slurp)
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}
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}
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//[END read]
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//[START copy]
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// copyFile copies a file in Google Cloud Storage.
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func (d *demo) copyFile(fileName string) {
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copyName := fileName + "-copy"
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fmt.Fprintf(d.w, "Copying file /%v/%v to /%v/%v:\n", d.bucket, fileName, d.bucketName, copyName)
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obj, err := d.bucket.Object(copyName).CopierFrom(d.bucket.Object(fileName)).Run(d.ctx)
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if err != nil {
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d.errorf("copyFile: unable to copy /%v/%v to bucket %q, file %q: %v", d.bucketName, fileName, d.bucketName, copyName, err)
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return
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}
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d.cleanUp = append(d.cleanUp, copyName)
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d.dumpStats(obj)
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}
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//[END copy]
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func (d *demo) dumpStats(obj *storage.ObjectAttrs) {
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fmt.Fprintf(d.w, "(filename: /%v/%v, ", obj.Bucket, obj.Name)
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fmt.Fprintf(d.w, "ContentType: %q, ", obj.ContentType)
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fmt.Fprintf(d.w, "ACL: %#v, ", obj.ACL)
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fmt.Fprintf(d.w, "Owner: %v, ", obj.Owner)
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fmt.Fprintf(d.w, "ContentEncoding: %q, ", obj.ContentEncoding)
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fmt.Fprintf(d.w, "Size: %v, ", obj.Size)
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fmt.Fprintf(d.w, "MD5: %q, ", obj.MD5)
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fmt.Fprintf(d.w, "CRC32C: %q, ", obj.CRC32C)
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fmt.Fprintf(d.w, "Metadata: %#v, ", obj.Metadata)
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fmt.Fprintf(d.w, "MediaLink: %q, ", obj.MediaLink)
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fmt.Fprintf(d.w, "StorageClass: %q, ", obj.StorageClass)
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if !obj.Deleted.IsZero() {
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fmt.Fprintf(d.w, "Deleted: %v, ", obj.Deleted)
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}
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fmt.Fprintf(d.w, "Updated: %v)\n", obj.Updated)
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}
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//[START file_metadata]
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// statFile reads the stats of the named file in Google Cloud Storage.
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func (d *demo) statFile(fileName string) {
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io.WriteString(d.w, "\nFile stat:\n")
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obj, err := d.bucket.Object(fileName).Attrs(d.ctx)
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if err != nil {
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d.errorf("statFile: unable to stat file from bucket %q, file %q: %v", d.bucketName, fileName, err)
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return
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}
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d.dumpStats(obj)
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}
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//[END file_metadata]
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// createListFiles creates files that will be used by listBucket.
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func (d *demo) createListFiles() {
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io.WriteString(d.w, "\nCreating more files for listbucket...\n")
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for _, n := range []string{"foo1", "foo2", "bar", "bar/1", "bar/2", "boo/"} {
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d.createFile(n)
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}
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}
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//[START list_bucket]
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// listBucket lists the contents of a bucket in Google Cloud Storage.
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func (d *demo) listBucket() {
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io.WriteString(d.w, "\nListbucket result:\n")
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query := &storage.Query{Prefix: "foo"}
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it := d.bucket.Objects(d.ctx, query)
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for {
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obj, err := it.Next()
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if err == iterator.Done {
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break
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}
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if err != nil {
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d.errorf("listBucket: unable to list bucket %q: %v", d.bucketName, err)
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return
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}
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d.dumpStats(obj)
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}
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}
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//[END list_bucket]
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func (d *demo) listDir(name, indent string) {
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query := &storage.Query{Prefix: name, Delimiter: "/"}
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it := d.bucket.Objects(d.ctx, query)
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for {
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obj, err := it.Next()
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if err == iterator.Done {
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break
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}
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if err != nil {
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d.errorf("listBucketDirMode: unable to list bucket %q: %v", d.bucketName, err)
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return
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}
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if obj.Prefix == "" {
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fmt.Fprint(d.w, indent)
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d.dumpStats(obj)
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continue
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}
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fmt.Fprintf(d.w, "%v(directory: /%v/%v)\n", indent, d.bucketName, obj.Prefix)
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d.listDir(obj.Prefix, indent+" ")
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}
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}
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// listBucketDirMode lists the contents of a bucket in dir mode in Google Cloud Storage.
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func (d *demo) listBucketDirMode() {
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io.WriteString(d.w, "\nListbucket directory mode result:\n")
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d.listDir("b", "")
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}
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// dumpDefaultACL prints out the default object ACL for this bucket.
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func (d *demo) dumpDefaultACL() {
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acl, err := d.bucket.ACL().List(d.ctx)
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if err != nil {
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d.errorf("defaultACL: unable to list default object ACL for bucket %q: %v", d.bucketName, err)
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return
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}
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for _, v := range acl {
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fmt.Fprintf(d.w, "Scope: %q, Permission: %q\n", v.Entity, v.Role)
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}
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}
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// defaultACL displays the default object ACL for this bucket.
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func (d *demo) defaultACL() {
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io.WriteString(d.w, "\nDefault object ACL:\n")
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d.dumpDefaultACL()
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}
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// putDefaultACLRule adds the "allUsers" default object ACL rule for this bucket.
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func (d *demo) putDefaultACLRule() {
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io.WriteString(d.w, "\nPut Default object ACL Rule:\n")
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err := d.bucket.DefaultObjectACL().Set(d.ctx, storage.AllUsers, storage.RoleReader)
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if err != nil {
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d.errorf("putDefaultACLRule: unable to save default object ACL rule for bucket %q: %v", d.bucketName, err)
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return
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}
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d.dumpDefaultACL()
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}
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// deleteDefaultACLRule deleted the "allUsers" default object ACL rule for this bucket.
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func (d *demo) deleteDefaultACLRule() {
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io.WriteString(d.w, "\nDelete Default object ACL Rule:\n")
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err := d.bucket.DefaultObjectACL().Delete(d.ctx, storage.AllUsers)
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if err != nil {
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d.errorf("deleteDefaultACLRule: unable to delete default object ACL rule for bucket %q: %v", d.bucketName, err)
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return
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}
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d.dumpDefaultACL()
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}
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// dumpBucketACL prints out the bucket ACL.
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func (d *demo) dumpBucketACL() {
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acl, err := d.bucket.ACL().List(d.ctx)
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if err != nil {
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d.errorf("dumpBucketACL: unable to list bucket ACL for bucket %q: %v", d.bucketName, err)
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return
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}
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for _, v := range acl {
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fmt.Fprintf(d.w, "Scope: %q, Permission: %q\n", v.Entity, v.Role)
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}
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}
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// bucketACL displays the bucket ACL for this bucket.
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func (d *demo) bucketACL() {
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io.WriteString(d.w, "\nBucket ACL:\n")
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d.dumpBucketACL()
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}
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// putBucketACLRule adds the "allUsers" bucket ACL rule for this bucket.
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func (d *demo) putBucketACLRule() {
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io.WriteString(d.w, "\nPut Bucket ACL Rule:\n")
|
||
|
|
err := d.bucket.ACL().Set(d.ctx, storage.AllUsers, storage.RoleReader)
|
||
|
|
if err != nil {
|
||
|
|
d.errorf("putBucketACLRule: unable to save bucket ACL rule for bucket %q: %v", d.bucketName, err)
|
||
|
|
return
|
||
|
|
}
|
||
|
|
d.dumpBucketACL()
|
||
|
|
}
|
||
|
|
|
||
|
|
// deleteBucketACLRule deleted the "allUsers" bucket ACL rule for this bucket.
|
||
|
|
func (d *demo) deleteBucketACLRule() {
|
||
|
|
io.WriteString(d.w, "\nDelete Bucket ACL Rule:\n")
|
||
|
|
err := d.bucket.ACL().Delete(d.ctx, storage.AllUsers)
|
||
|
|
if err != nil {
|
||
|
|
d.errorf("deleteBucketACLRule: unable to delete bucket ACL rule for bucket %q: %v", d.bucketName, err)
|
||
|
|
return
|
||
|
|
}
|
||
|
|
d.dumpBucketACL()
|
||
|
|
}
|
||
|
|
|
||
|
|
// dumpACL prints out the ACL of the named file.
|
||
|
|
func (d *demo) dumpACL(fileName string) {
|
||
|
|
acl, err := d.bucket.Object(fileName).ACL().List(d.ctx)
|
||
|
|
if err != nil {
|
||
|
|
d.errorf("dumpACL: unable to list file ACL for bucket %q, file %q: %v", d.bucketName, fileName, err)
|
||
|
|
return
|
||
|
|
}
|
||
|
|
for _, v := range acl {
|
||
|
|
fmt.Fprintf(d.w, "Scope: %q, Permission: %q\n", v.Entity, v.Role)
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
// acl displays the ACL for the named file.
|
||
|
|
func (d *demo) acl(fileName string) {
|
||
|
|
fmt.Fprintf(d.w, "\nACL for file %v:\n", fileName)
|
||
|
|
d.dumpACL(fileName)
|
||
|
|
}
|
||
|
|
|
||
|
|
// putACLRule adds the "allUsers" ACL rule for the named file.
|
||
|
|
func (d *demo) putACLRule(fileName string) {
|
||
|
|
fmt.Fprintf(d.w, "\nPut ACL rule for file %v:\n", fileName)
|
||
|
|
err := d.bucket.Object(fileName).ACL().Set(d.ctx, storage.AllUsers, storage.RoleReader)
|
||
|
|
if err != nil {
|
||
|
|
d.errorf("putACLRule: unable to save ACL rule for bucket %q, file %q: %v", d.bucketName, fileName, err)
|
||
|
|
return
|
||
|
|
}
|
||
|
|
d.dumpACL(fileName)
|
||
|
|
}
|
||
|
|
|
||
|
|
// deleteACLRule deleted the "allUsers" ACL rule for the named file.
|
||
|
|
func (d *demo) deleteACLRule(fileName string) {
|
||
|
|
fmt.Fprintf(d.w, "\nDelete ACL rule for file %v:\n", fileName)
|
||
|
|
err := d.bucket.Object(fileName).ACL().Delete(d.ctx, storage.AllUsers)
|
||
|
|
if err != nil {
|
||
|
|
d.errorf("deleteACLRule: unable to delete ACL rule for bucket %q, file %q: %v", d.bucketName, fileName, err)
|
||
|
|
return
|
||
|
|
}
|
||
|
|
d.dumpACL(fileName)
|
||
|
|
}
|
||
|
|
|
||
|
|
//[START delete]
|
||
|
|
// deleteFiles deletes all the temporary files from a bucket created by this demo.
|
||
|
|
func (d *demo) deleteFiles() {
|
||
|
|
io.WriteString(d.w, "\nDeleting files...\n")
|
||
|
|
for _, v := range d.cleanUp {
|
||
|
|
fmt.Fprintf(d.w, "Deleting file %v\n", v)
|
||
|
|
if err := d.bucket.Object(v).Delete(d.ctx); err != nil {
|
||
|
|
d.errorf("deleteFiles: unable to delete bucket %q, file %q: %v", d.bucketName, v, err)
|
||
|
|
return
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
//[END delete]
|