File: conn.go

package info (click to toggle)
golang-github-garyburd-redigo 0.0~git20150901.0.d8dbe4d-2
  • links: PTS, VCS
  • area: main
  • in suites: bullseye, buster, buster-backports, sid
  • size: 244 kB
  • ctags: 280
  • sloc: makefile: 3
file content (567 lines) | stat: -rw-r--r-- 12,751 bytes parent folder | download | duplicates (3)
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
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
// Copyright 2012 Gary Burd
//
// 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.

package redis

import (
	"bufio"
	"bytes"
	"errors"
	"fmt"
	"io"
	"net"
	"net/url"
	"regexp"
	"strconv"
	"sync"
	"time"
)

// conn is the low-level implementation of Conn
type conn struct {

	// Shared
	mu      sync.Mutex
	pending int
	err     error
	conn    net.Conn

	// Read
	readTimeout time.Duration
	br          *bufio.Reader

	// Write
	writeTimeout time.Duration
	bw           *bufio.Writer

	// Scratch space for formatting argument length.
	// '*' or '$', length, "\r\n"
	lenScratch [32]byte

	// Scratch space for formatting integers and floats.
	numScratch [40]byte
}

// DialTimeout acts like Dial but takes timeouts for establishing the
// connection to the server, writing a command and reading a reply.
//
// DialTimeout is deprecated.
func DialTimeout(network, address string, connectTimeout, readTimeout, writeTimeout time.Duration) (Conn, error) {
	return Dial(network, address,
		DialConnectTimeout(connectTimeout),
		DialReadTimeout(readTimeout),
		DialWriteTimeout(writeTimeout))
}

// DialOption specifies an option for dialing a Redis server.
type DialOption struct {
	f func(*dialOptions)
}

type dialOptions struct {
	readTimeout  time.Duration
	writeTimeout time.Duration
	dial         func(network, addr string) (net.Conn, error)
	db           int
	password     string
}

// DialReadTimeout specifies the timeout for reading a single command reply.
func DialReadTimeout(d time.Duration) DialOption {
	return DialOption{func(do *dialOptions) {
		do.readTimeout = d
	}}
}

// DialWriteTimeout specifies the timeout for writing a single command.
func DialWriteTimeout(d time.Duration) DialOption {
	return DialOption{func(do *dialOptions) {
		do.writeTimeout = d
	}}
}

// DialConnectTimeout specifies the timeout for connecting to the Redis server.
func DialConnectTimeout(d time.Duration) DialOption {
	return DialOption{func(do *dialOptions) {
		dialer := net.Dialer{Timeout: d}
		do.dial = dialer.Dial
	}}
}

// DialNetDial specifies a custom dial function for creating TCP
// connections. If this option is left out, then net.Dial is
// used. DialNetDial overrides DialConnectTimeout.
func DialNetDial(dial func(network, addr string) (net.Conn, error)) DialOption {
	return DialOption{func(do *dialOptions) {
		do.dial = dial
	}}
}

// DialDatabase specifies the database to select when dialing a connection.
func DialDatabase(db int) DialOption {
	return DialOption{func(do *dialOptions) {
		do.db = db
	}}
}

// DialPassword specifies the password to use when connecting to
// the Redis server.
func DialPassword(password string) DialOption {
	return DialOption{func(do *dialOptions) {
		do.password = password
	}}
}

// Dial connects to the Redis server at the given network and
// address using the specified options.
func Dial(network, address string, options ...DialOption) (Conn, error) {
	do := dialOptions{
		dial: net.Dial,
	}
	for _, option := range options {
		option.f(&do)
	}

	netConn, err := do.dial(network, address)
	if err != nil {
		return nil, err
	}
	c := &conn{
		conn:         netConn,
		bw:           bufio.NewWriter(netConn),
		br:           bufio.NewReader(netConn),
		readTimeout:  do.readTimeout,
		writeTimeout: do.writeTimeout,
	}

	if do.password != "" {
		if _, err := c.Do("AUTH", do.password); err != nil {
			netConn.Close()
			return nil, err
		}
	}

	if do.db != 0 {
		if _, err := c.Do("SELECT", do.db); err != nil {
			netConn.Close()
			return nil, err
		}
	}

	return c, nil
}

var pathDBRegexp = regexp.MustCompile(`/(\d)\z`)

// DialURL connects to a Redis server at the given URL using the Redis
// URI scheme. URLs should follow the draft IANA specification for the
// scheme (https://www.iana.org/assignments/uri-schemes/prov/redis).
func DialURL(rawurl string, options ...DialOption) (Conn, error) {
	u, err := url.Parse(rawurl)
	if err != nil {
		return nil, err
	}

	if u.Scheme != "redis" {
		return nil, fmt.Errorf("invalid redis URL scheme: %s", u.Scheme)
	}

	// As per the IANA draft spec, the host defaults to localhost and
	// the port defaults to 6379.
	host, port, err := net.SplitHostPort(u.Host)
	if err != nil {
		// assume port is missing
		host = u.Host
		port = "6379"
	}
	if host == "" {
		host = "localhost"
	}
	address := net.JoinHostPort(host, port)

	if u.User != nil {
		password, isSet := u.User.Password()
		if isSet {
			options = append(options, DialPassword(password))
		}
	}

	match := pathDBRegexp.FindStringSubmatch(u.Path)
	if len(match) == 2 {
		db, err := strconv.Atoi(match[1])
		if err != nil {
			return nil, fmt.Errorf("invalid database: %s", u.Path[1:])
		}
		if db != 0 {
			options = append(options, DialDatabase(db))
		}
	} else if u.Path != "" {
		return nil, fmt.Errorf("invalid database: %s", u.Path[1:])
	}

	return Dial("tcp", address, options...)
}

// NewConn returns a new Redigo connection for the given net connection.
func NewConn(netConn net.Conn, readTimeout, writeTimeout time.Duration) Conn {
	return &conn{
		conn:         netConn,
		bw:           bufio.NewWriter(netConn),
		br:           bufio.NewReader(netConn),
		readTimeout:  readTimeout,
		writeTimeout: writeTimeout,
	}
}

func (c *conn) Close() error {
	c.mu.Lock()
	err := c.err
	if c.err == nil {
		c.err = errors.New("redigo: closed")
		err = c.conn.Close()
	}
	c.mu.Unlock()
	return err
}

func (c *conn) fatal(err error) error {
	c.mu.Lock()
	if c.err == nil {
		c.err = err
		// Close connection to force errors on subsequent calls and to unblock
		// other reader or writer.
		c.conn.Close()
	}
	c.mu.Unlock()
	return err
}

func (c *conn) Err() error {
	c.mu.Lock()
	err := c.err
	c.mu.Unlock()
	return err
}

func (c *conn) writeLen(prefix byte, n int) error {
	c.lenScratch[len(c.lenScratch)-1] = '\n'
	c.lenScratch[len(c.lenScratch)-2] = '\r'
	i := len(c.lenScratch) - 3
	for {
		c.lenScratch[i] = byte('0' + n%10)
		i -= 1
		n = n / 10
		if n == 0 {
			break
		}
	}
	c.lenScratch[i] = prefix
	_, err := c.bw.Write(c.lenScratch[i:])
	return err
}

func (c *conn) writeString(s string) error {
	c.writeLen('$', len(s))
	c.bw.WriteString(s)
	_, err := c.bw.WriteString("\r\n")
	return err
}

func (c *conn) writeBytes(p []byte) error {
	c.writeLen('$', len(p))
	c.bw.Write(p)
	_, err := c.bw.WriteString("\r\n")
	return err
}

func (c *conn) writeInt64(n int64) error {
	return c.writeBytes(strconv.AppendInt(c.numScratch[:0], n, 10))
}

func (c *conn) writeFloat64(n float64) error {
	return c.writeBytes(strconv.AppendFloat(c.numScratch[:0], n, 'g', -1, 64))
}

func (c *conn) writeCommand(cmd string, args []interface{}) (err error) {
	c.writeLen('*', 1+len(args))
	err = c.writeString(cmd)
	for _, arg := range args {
		if err != nil {
			break
		}
		switch arg := arg.(type) {
		case string:
			err = c.writeString(arg)
		case []byte:
			err = c.writeBytes(arg)
		case int:
			err = c.writeInt64(int64(arg))
		case int64:
			err = c.writeInt64(arg)
		case float64:
			err = c.writeFloat64(arg)
		case bool:
			if arg {
				err = c.writeString("1")
			} else {
				err = c.writeString("0")
			}
		case nil:
			err = c.writeString("")
		default:
			var buf bytes.Buffer
			fmt.Fprint(&buf, arg)
			err = c.writeBytes(buf.Bytes())
		}
	}
	return err
}

type protocolError string

func (pe protocolError) Error() string {
	return fmt.Sprintf("redigo: %s (possible server error or unsupported concurrent read by application)", string(pe))
}

func (c *conn) readLine() ([]byte, error) {
	p, err := c.br.ReadSlice('\n')
	if err == bufio.ErrBufferFull {
		return nil, protocolError("long response line")
	}
	if err != nil {
		return nil, err
	}
	i := len(p) - 2
	if i < 0 || p[i] != '\r' {
		return nil, protocolError("bad response line terminator")
	}
	return p[:i], nil
}

// parseLen parses bulk string and array lengths.
func parseLen(p []byte) (int, error) {
	if len(p) == 0 {
		return -1, protocolError("malformed length")
	}

	if p[0] == '-' && len(p) == 2 && p[1] == '1' {
		// handle $-1 and $-1 null replies.
		return -1, nil
	}

	var n int
	for _, b := range p {
		n *= 10
		if b < '0' || b > '9' {
			return -1, protocolError("illegal bytes in length")
		}
		n += int(b - '0')
	}

	return n, nil
}

// parseInt parses an integer reply.
func parseInt(p []byte) (interface{}, error) {
	if len(p) == 0 {
		return 0, protocolError("malformed integer")
	}

	var negate bool
	if p[0] == '-' {
		negate = true
		p = p[1:]
		if len(p) == 0 {
			return 0, protocolError("malformed integer")
		}
	}

	var n int64
	for _, b := range p {
		n *= 10
		if b < '0' || b > '9' {
			return 0, protocolError("illegal bytes in length")
		}
		n += int64(b - '0')
	}

	if negate {
		n = -n
	}
	return n, nil
}

var (
	okReply   interface{} = "OK"
	pongReply interface{} = "PONG"
)

func (c *conn) readReply() (interface{}, error) {
	line, err := c.readLine()
	if err != nil {
		return nil, err
	}
	if len(line) == 0 {
		return nil, protocolError("short response line")
	}
	switch line[0] {
	case '+':
		switch {
		case len(line) == 3 && line[1] == 'O' && line[2] == 'K':
			// Avoid allocation for frequent "+OK" response.
			return okReply, nil
		case len(line) == 5 && line[1] == 'P' && line[2] == 'O' && line[3] == 'N' && line[4] == 'G':
			// Avoid allocation in PING command benchmarks :)
			return pongReply, nil
		default:
			return string(line[1:]), nil
		}
	case '-':
		return Error(string(line[1:])), nil
	case ':':
		return parseInt(line[1:])
	case '$':
		n, err := parseLen(line[1:])
		if n < 0 || err != nil {
			return nil, err
		}
		p := make([]byte, n)
		_, err = io.ReadFull(c.br, p)
		if err != nil {
			return nil, err
		}
		if line, err := c.readLine(); err != nil {
			return nil, err
		} else if len(line) != 0 {
			return nil, protocolError("bad bulk string format")
		}
		return p, nil
	case '*':
		n, err := parseLen(line[1:])
		if n < 0 || err != nil {
			return nil, err
		}
		r := make([]interface{}, n)
		for i := range r {
			r[i], err = c.readReply()
			if err != nil {
				return nil, err
			}
		}
		return r, nil
	}
	return nil, protocolError("unexpected response line")
}

func (c *conn) Send(cmd string, args ...interface{}) error {
	c.mu.Lock()
	c.pending += 1
	c.mu.Unlock()
	if c.writeTimeout != 0 {
		c.conn.SetWriteDeadline(time.Now().Add(c.writeTimeout))
	}
	if err := c.writeCommand(cmd, args); err != nil {
		return c.fatal(err)
	}
	return nil
}

func (c *conn) Flush() error {
	if c.writeTimeout != 0 {
		c.conn.SetWriteDeadline(time.Now().Add(c.writeTimeout))
	}
	if err := c.bw.Flush(); err != nil {
		return c.fatal(err)
	}
	return nil
}

func (c *conn) Receive() (reply interface{}, err error) {
	if c.readTimeout != 0 {
		c.conn.SetReadDeadline(time.Now().Add(c.readTimeout))
	}
	if reply, err = c.readReply(); err != nil {
		return nil, c.fatal(err)
	}
	// When using pub/sub, the number of receives can be greater than the
	// number of sends. To enable normal use of the connection after
	// unsubscribing from all channels, we do not decrement pending to a
	// negative value.
	//
	// The pending field is decremented after the reply is read to handle the
	// case where Receive is called before Send.
	c.mu.Lock()
	if c.pending > 0 {
		c.pending -= 1
	}
	c.mu.Unlock()
	if err, ok := reply.(Error); ok {
		return nil, err
	}
	return
}

func (c *conn) Do(cmd string, args ...interface{}) (interface{}, error) {
	c.mu.Lock()
	pending := c.pending
	c.pending = 0
	c.mu.Unlock()

	if cmd == "" && pending == 0 {
		return nil, nil
	}

	if c.writeTimeout != 0 {
		c.conn.SetWriteDeadline(time.Now().Add(c.writeTimeout))
	}

	if cmd != "" {
		if err := c.writeCommand(cmd, args); err != nil {
			return nil, c.fatal(err)
		}
	}

	if err := c.bw.Flush(); err != nil {
		return nil, c.fatal(err)
	}

	if c.readTimeout != 0 {
		c.conn.SetReadDeadline(time.Now().Add(c.readTimeout))
	}

	if cmd == "" {
		reply := make([]interface{}, pending)
		for i := range reply {
			r, e := c.readReply()
			if e != nil {
				return nil, c.fatal(e)
			}
			reply[i] = r
		}
		return reply, nil
	}

	var err error
	var reply interface{}
	for i := 0; i <= pending; i++ {
		var e error
		if reply, e = c.readReply(); e != nil {
			return nil, c.fatal(e)
		}
		if e, ok := reply.(Error); ok && err == nil {
			err = e
		}
	}
	return reply, err
}