1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
|
// Copyright 2019 Google LLC
//
// 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
//
// https://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 builder
import (
"context"
"io"
"log"
"os"
"sync"
"cloud.google.com/go/storage"
)
type void struct{}
// LocalCache implements the structure used for local caching of
// manifests and layer uploads.
type LocalCache struct {
mmtx sync.RWMutex
mcache map[string]string
lmtx sync.RWMutex
lcache map[string]void
}
func NewCache() LocalCache {
return LocalCache{
mcache: make(map[string]string),
lcache: make(map[string]void),
}
}
// Has this layer hash already been seen by this Nixery instance? If
// yes, we can skip upload checking and such because it has already
// been done.
func (c *LocalCache) hasSeenLayer(hash string) bool {
c.lmtx.RLock()
defer c.lmtx.RUnlock()
_, seen := c.lcache[hash]
return seen
}
// Layer has now been seen and should be stored.
func (c *LocalCache) sawLayer(hash string) {
c.lmtx.Lock()
defer c.lmtx.Unlock()
c.lcache[hash] = void{}
}
// Retrieve a cached manifest if the build is cacheable and it exists.
func (c *LocalCache) manifestFromLocalCache(key string) (string, bool) {
c.mmtx.RLock()
path, ok := c.mcache[key]
c.mmtx.RUnlock()
if !ok {
return "", false
}
return path, true
}
// Adds the result of a manifest build to the local cache, if the
// manifest is considered cacheable.
func (c *LocalCache) localCacheManifest(key, path string) {
c.mmtx.Lock()
c.mcache[key] = path
c.mmtx.Unlock()
}
// Retrieve a manifest from the cache(s). First the local cache is
// checked, then the GCS-bucket cache.
func manifestFromCache(ctx *context.Context, cache *LocalCache, bucket *storage.BucketHandle, key string) (string, bool) {
path, cached := cache.manifestFromLocalCache(key)
if cached {
return path, true
}
obj := bucket.Object("manifests/" + key)
// Probe whether the file exists before trying to fetch it.
_, err := obj.Attrs(*ctx)
if err != nil {
return "", false
}
r, err := obj.NewReader(*ctx)
if err != nil {
log.Printf("Failed to retrieve manifest '%s' from cache: %s\n", key, err)
return "", false
}
defer r.Close()
path = os.TempDir() + "/" + key
f, _ := os.Create(path)
defer f.Close()
_, err = io.Copy(f, r)
if err != nil {
log.Printf("Failed to read cached manifest for '%s': %s\n", key, err)
}
log.Printf("Retrieved manifest for sha1:%s from GCS\n", key)
cache.localCacheManifest(key, path)
return path, true
}
func cacheManifest(ctx *context.Context, cache *LocalCache, bucket *storage.BucketHandle, key, path string) {
cache.localCacheManifest(key, path)
obj := bucket.Object("manifests/" + key)
w := obj.NewWriter(*ctx)
f, err := os.Open(path)
if err != nil {
log.Printf("failed to open manifest sha1:%s for cache upload: %s\n", key, err)
return
}
defer f.Close()
size, err := io.Copy(w, f)
if err != nil {
log.Printf("failed to cache manifest sha1:%s: %s\n", key, err)
return
}
if err = w.Close(); err != nil {
log.Printf("failed to cache manifest sha1:%s: %s\n", key, err)
return
}
log.Printf("Cached manifest sha1:%s (%v bytes written)\n", key, size)
}
|
