gifs/api
2014-08-27
Child:1bbbe113f599
gifs/api/storage.go
Spike out functionality and tests. Create our interfaces around storing data and retrieving it. Create an in-memory implementation of our interfaces, for testing and rapid dev purposes. Begin sketching out what our unit tests look like. Create our Google Cloud Storage datastore implementation. Sketch out an idea for a usage collection process to keep track of which users are actually using stuff.
1 package api
3 import (
4 "errors"
5 "io"
6 "io/ioutil"
7 "log"
8 "net/http"
10 "code.google.com/p/google-api-go-client/googleapi"
11 "code.google.com/p/google-api-go-client/storage/v1beta2"
12 )
14 var (
15 BucketNotFoundError = errors.New("bucket not found")
16 BlobNotFoundError = errors.New("blob not found")
17 )
19 type Storage interface {
20 Upload(bucket, tmp string, r io.Reader, errs chan error, done chan struct{})
21 Delete(bucket, tmp string) error
22 Move(srcBucket, src, dstBucket, dst string) error
23 Download(bucket, id string, w io.Writer) (int64, error)
24 }
26 type GoogleCloudStorage struct {
27 *storage.Service
28 }
30 func (gcs *GoogleCloudStorage) Upload(bucket, tmp string, r io.Reader, errs chan error, done chan struct{}) {
31 if errs != nil {
32 defer close(errs)
33 }
34 if done != nil {
35 defer close(done)
36 }
37 object := &storage.Object{Name: tmp}
38 _, err := gcs.Objects.Insert(bucket, object).Media(r).Do()
39 if err != nil && errs != nil {
40 errs <- err
41 }
42 }
44 func (gcs *GoogleCloudStorage) Delete(bucket, tmp string) error {
45 return gcs.Objects.Delete(bucket, tmp).Do()
46 }
48 func (gcs *GoogleCloudStorage) Move(srcBucket, src, dstBucket, dst string) error {
49 _, err := gcs.Objects.Get(dstBucket, dst).Do()
50 if err == nil {
51 go gcs.del(srcBucket, src)
52 return nil
53 }
54 if e, ok := err.(*googleapi.Error); !ok || e.Code != 404 {
55 return err
56 }
57 _, err = gcs.Objects.Copy(srcBucket, src, dstBucket, dst, nil).Do()
58 if err != nil {
59 return err
60 }
61 objectAcl := &storage.ObjectAccessControl{
62 Bucket: dstBucket, Entity: "allUsers", Object: dst, Role: "READER",
63 }
64 _, err = gcs.ObjectAccessControls.Insert(dstBucket, dst, objectAcl).Do()
65 if err != nil {
66 return err
67 }
68 go gcs.del(srcBucket, src)
69 return nil
70 }
72 func (gcs *GoogleCloudStorage) del(bucket, tmp string) {
73 err := gcs.Delete(bucket, tmp)
74 if err != nil {
75 log.Printf("Error deleting temporary upload %s in %s: %s\n", tmp, bucket, err)
76 }
77 }
79 func (gcs *GoogleCloudStorage) Download(bucket, id string, w io.Writer) (int64, error) {
80 res, err := gcs.Objects.Get(bucket, id).Do()
81 if err != nil {
82 return 0, err
83 }
84 resp, err := http.Get(res.MediaLink)
85 if err != nil {
86 return 0, err
87 }
88 defer resp.Body.Close()
89 return io.Copy(w, resp.Body)
90 }
92 type Memstorage map[string]Bucket
94 type Bucket map[string][]byte
96 func (m Memstorage) Upload(bucket, tmp string, r io.Reader, errs chan error, done chan struct{}) {
97 if errs != nil {
98 defer close(errs)
99 }
100 if done != nil {
101 defer close(done)
102 }
103 if _, ok := m[bucket]; !ok {
104 m[bucket] = make(Bucket)
105 }
106 bytes, err := ioutil.ReadAll(r)
107 if err != nil {
108 errs <- err
109 return
110 }
111 m[bucket][tmp] = bytes
112 }
114 func (m Memstorage) Delete(bucket, tmp string) error {
115 delete(m[bucket], tmp)
116 return nil
117 }
119 func (m Memstorage) Move(srcBucket, src, dstBucket, dst string) error {
120 if _, ok := m[srcBucket]; !ok {
121 return BucketNotFoundError
122 }
123 if _, ok := m[srcBucket][src]; !ok {
124 return BlobNotFoundError
125 }
126 if _, ok := m[dstBucket]; !ok {
127 m[dstBucket] = make(Bucket)
128 }
129 m[dstBucket][dst] = m[srcBucket][src]
130 return m.Delete(srcBucket, src)
131 }
133 func (m Memstorage) Download(bucket, id string, w io.Writer) (int64, error) {
134 if _, ok := m[bucket]; !ok {
135 return 0, BucketNotFoundError
136 }
137 if _, ok := m[bucket][id]; !ok {
138 return 0, BlobNotFoundError
139 }
140 n, err := w.Write(m[bucket][id])
141 return int64(n), err
142 }