-
Notifications
You must be signed in to change notification settings - Fork 0
/
filecache.go
310 lines (232 loc) · 6.34 KB
/
filecache.go
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
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
package filecache
import (
"bytes"
"context"
"fmt"
"io"
"os"
"time"
)
const (
// TTLEternal is a TTL value for eternal cache.
TTLEternal = time.Duration(-1)
)
// New creates a new FileCache instance with a specified target dir & options.
func New(targetDir string, options ...InstanceOptions) (FileCache, error) {
if len(options) > 1 {
return nil, fmt.Errorf("more than one instance options param behavior is not supported")
}
targetDir = fixSeparators(targetDir)
if targetDir == "" {
targetDir = os.TempDir()
}
if err := prepareDir(targetDir); err != nil {
return nil, err
}
fc := &fileCache{
dir: targetDir,
ttlDefault: TTLEternal,
pathGenerator: HashedKeySplitPath,
gc: NewProbabilityGarbageCollector(targetDir, 1, 100),
keysLocker: newKeysLocker(),
}
if len(options) == 1 {
if options[0].DefaultTTL != 0 {
fc.ttlDefault = options[0].DefaultTTL
}
if options[0].GC != nil {
fc.gc = options[0].GC
} else if options[0].GCDivisor != 0 {
fc.gc = NewProbabilityGarbageCollector(targetDir, 1, options[0].GCDivisor)
}
if options[0].PathGenerator != nil {
fc.pathGenerator = options[0].PathGenerator
}
}
go fc.gc.OnInstanceInit()
return fc, nil
}
// NewInTemp creates a new FileCache instance with files stored in the system's temp dir.
func NewInTemp(options ...InstanceOptions) (FileCache, error) {
return New("", options...)
}
// FileCache is a tool to cache data from any io.Reader to the file.
type FileCache interface {
// GetPath returns the target path of the FileCache instance.
GetPath() string
// Write writes data from the reader to the cache file.
Write(ctx context.Context, key string, reader io.Reader, options ...ItemOptions) (written int64, err error)
// WriteData writes data to the cache file.
WriteData(ctx context.Context, key string, data []byte, options ...ItemOptions) (written int64, err error)
// Open opens the reader with cached data.
//
// Returns no error on successful cache hit, on no hit, on invalid cache files.
// Returns an error if failed to open an existing cache file or if context is done.
Open(ctx context.Context, key string) (result *OpenResult, err error)
// Read reads data from the cache file.
//
// Returns no error on successful cache hit, on no hit, on invalid cache files.
// Returns an error if failed to open or read an existing cache file or if context is done.
Read(ctx context.Context, key string) (result *ReadResult, err error)
// Invalidate removes data associated with a key from a cache.
Invalidate(ctx context.Context, key string) error
// Close closes the FileCache instance.
Close() error
}
type fileCache struct {
dir string
pathGenerator PathGeneratorFn
ttlDefault time.Duration
gc GarbageCollector
keysLocker *keysLocker
}
func (fc *fileCache) GetPath() string {
return fc.dir
}
//nolint:funlen
func (fc *fileCache) Write(
ctx context.Context,
key string,
reader io.Reader,
options ...ItemOptions,
) (written int64, err error) {
if err := ctx.Err(); err != nil {
return 0, err
}
defer func() {
go fc.gc.OnOperation()
}()
opt := ItemOptions{}
if len(options) > 0 {
opt = options[0]
}
fc.keysLocker.lock(key)
defer fc.keysLocker.unlock(key)
meta := newMeta(key, &opt, fc.ttlDefault)
itemPath := fc.getItemPath(key, false, true)
metaPath := fc.getItemPath(key, true, true)
itemF, err := create(key, itemPath)
if err != nil {
return 0, err
}
defer func() {
_ = itemF.Close()
}()
metaF, err := create(key, metaPath)
if err != nil {
_ = itemF.Close()
invalidate(itemPath, "")
return 0, err
}
defer func() {
_ = metaF.Close()
}()
undo := func() {
_ = itemF.Close()
_ = metaF.Close()
invalidate(itemPath, metaPath)
}
if err := saveMeta(ctx, meta, metaF); err != nil {
undo()
return 0, err
}
n, err := copyWithCtx(ctx, itemF, reader)
if err != nil {
undo()
return 0, err
}
return n, nil
}
func (fc *fileCache) WriteData(
ctx context.Context,
key string,
data []byte,
options ...ItemOptions,
) (written int64, err error) {
reader := bytes.NewReader(data)
return fc.Write(ctx, key, reader, options...)
}
func (fc *fileCache) Open(ctx context.Context, key string) (result *OpenResult, err error) {
if err := ctx.Err(); err != nil {
return nil, err
}
defer func() {
go fc.gc.OnOperation()
}()
result = &OpenResult{}
fc.keysLocker.lock(key)
defer fc.keysLocker.unlock(key)
itemPath := fc.getItemPath(key, false, false)
metaPath := fc.getItemPath(key, true, false)
if !itemFilesValid(itemPath, metaPath) {
invalidate(itemPath, metaPath)
return result, nil
}
meta, err := readMeta(key, metaPath)
if err != nil {
invalidate(itemPath, metaPath)
return result, nil
}
if meta.isExpired() {
invalidate(itemPath, metaPath)
return result, nil
}
result.hit = true
result.options = metaToOptions(meta)
result.reader, err = os.Open(itemPath)
if err != nil {
invalidate(itemPath, metaPath)
return nil, fmt.Errorf("failed to open cache file for key %s: %w", key, err)
}
return result, nil
}
func (fc *fileCache) Read(ctx context.Context, key string) (result *ReadResult, err error) {
if err := ctx.Err(); err != nil {
return nil, err
}
defer func() {
go fc.gc.OnOperation()
}()
itemPath := fc.getItemPath(key, false, false)
metaPath := fc.getItemPath(key, true, false)
openRes, err := fc.Open(ctx, key)
if err != nil {
return nil, err
}
result = &ReadResult{}
if !openRes.Hit() {
return result, nil
}
data, err := readAll(ctx, openRes.reader)
if err != nil {
invalidate(itemPath, metaPath)
return nil, fmt.Errorf("failed to read cache data for key %s: %w", key, err)
}
result.hit = true
result.options = openRes.options
result.data = data
return result, nil
}
func (fc *fileCache) Invalidate(ctx context.Context, key string) error {
if err := ctx.Err(); err != nil {
return err
}
defer func() {
go fc.gc.OnOperation()
}()
fc.keysLocker.lock(key)
defer fc.keysLocker.unlock(key)
itemPath := fc.getItemPath(key, false, false)
metaPath := fc.getItemPath(key, true, false)
invalidate(itemPath, metaPath)
return nil
}
func (fc *fileCache) Close() error {
if err := fc.gc.Close(); err != nil {
return err
}
return nil
}
func (fc *fileCache) getItemPath(key string, forMeta bool, createDirs bool) string {
return getItemPath(fc.GetPath(), fc.pathGenerator, key, forMeta, createDirs)
}