aboutsummaryrefslogtreecommitdiff
path: root/vendor/gopkg.in/mgo.v2/server.go
blob: f6773593a9a01f85611ff82555eb6ca315340fc8 (plain)
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
// mgo - MongoDB driver for Go
//
// Copyright (c) 2010-2012 - Gustavo Niemeyer <gustavo@niemeyer.net>
//
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice, this
//    list of conditions and the following disclaimer.
// 2. Redistributions in binary form must reproduce the above copyright notice,
//    this list of conditions and the following disclaimer in the documentation
//    and/or other materials provided with the distribution.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
// ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
// LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
// ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

package mgo

import (
	"errors"
	"net"
	"sort"
	"sync"
	"time"

	"gopkg.in/mgo.v2/bson"
)

// ---------------------------------------------------------------------------
// Mongo server encapsulation.

type mongoServer struct {
	sync.RWMutex
	Addr          string
	ResolvedAddr  string
	tcpaddr       *net.TCPAddr
	unusedSockets []*mongoSocket
	liveSockets   []*mongoSocket
	closed        bool
	abended       bool
	sync          chan bool
	dial          dialer
	pingValue     time.Duration
	pingIndex     int
	pingCount     uint32
	pingWindow    [6]time.Duration
	info          *mongoServerInfo
}

type dialer struct {
	old func(addr net.Addr) (net.Conn, error)
	new func(addr *ServerAddr) (net.Conn, error)
}

func (dial dialer) isSet() bool {
	return dial.old != nil || dial.new != nil
}

type mongoServerInfo struct {
	Master         bool
	Mongos         bool
	Tags           bson.D
	MaxWireVersion int
	SetName        string
}

var defaultServerInfo mongoServerInfo

func newServer(addr string, tcpaddr *net.TCPAddr, sync chan bool, dial dialer) *mongoServer {
	server := &mongoServer{
		Addr:         addr,
		ResolvedAddr: tcpaddr.String(),
		tcpaddr:      tcpaddr,
		sync:         sync,
		dial:         dial,
		info:         &defaultServerInfo,
		pingValue:    time.Hour, // Push it back before an actual ping.
	}
	go server.pinger(true)
	return server
}

var errPoolLimit = errors.New("per-server connection limit reached")
var errServerClosed = errors.New("server was closed")

// AcquireSocket returns a socket for communicating with the server.
// This will attempt to reuse an old connection, if one is available. Otherwise,
// it will establish a new one. The returned socket is owned by the call site,
// and will return to the cache when the socket has its Release method called
// the same number of times as AcquireSocket + Acquire were called for it.
// If the poolLimit argument is greater than zero and the number of sockets in
// use in this server is greater than the provided limit, errPoolLimit is
// returned.
func (server *mongoServer) AcquireSocket(poolLimit int, timeout time.Duration) (socket *mongoSocket, abended bool, err error) {
	for {
		server.Lock()
		abended = server.abended
		if server.closed {
			server.Unlock()
			return nil, abended, errServerClosed
		}
		n := len(server.unusedSockets)
		if poolLimit > 0 && len(server.liveSockets)-n >= poolLimit {
			server.Unlock()
			return nil, false, errPoolLimit
		}
		if n > 0 {
			socket = server.unusedSockets[n-1]
			server.unusedSockets[n-1] = nil // Help GC.
			server.unusedSockets = server.unusedSockets[:n-1]
			info := server.info
			server.Unlock()
			err = socket.InitialAcquire(info, timeout)
			if err != nil {
				continue
			}
		} else {
			server.Unlock()
			socket, err = server.Connect(timeout)
			if err == nil {
				server.Lock()
				// We've waited for the Connect, see if we got
				// closed in the meantime
				if server.closed {
					server.Unlock()
					socket.Release()
					socket.Close()
					return nil, abended, errServerClosed
				}
				server.liveSockets = append(server.liveSockets, socket)
				server.Unlock()
			}
		}
		return
	}
	panic("unreachable")
}

// Connect establishes a new connection to the server. This should
// generally be done through server.AcquireSocket().
func (server *mongoServer) Connect(timeout time.Duration) (*mongoSocket, error) {
	server.RLock()
	master := server.info.Master
	dial := server.dial
	server.RUnlock()

	logf("Establishing new connection to %s (timeout=%s)...", server.Addr, timeout)
	var conn net.Conn
	var err error
	switch {
	case !dial.isSet():
		// Cannot do this because it lacks timeout support. :-(
		//conn, err = net.DialTCP("tcp", nil, server.tcpaddr)
		conn, err = net.DialTimeout("tcp", server.ResolvedAddr, timeout)
		if tcpconn, ok := conn.(*net.TCPConn); ok {
			tcpconn.SetKeepAlive(true)
		} else if err == nil {
			panic("internal error: obtained TCP connection is not a *net.TCPConn!?")
		}
	case dial.old != nil:
		conn, err = dial.old(server.tcpaddr)
	case dial.new != nil:
		conn, err = dial.new(&ServerAddr{server.Addr, server.tcpaddr})
	default:
		panic("dialer is set, but both dial.old and dial.new are nil")
	}
	if err != nil {
		logf("Connection to %s failed: %v", server.Addr, err.Error())
		return nil, err
	}
	logf("Connection to %s established.", server.Addr)

	stats.conn(+1, master)
	return newSocket(server, conn, timeout), nil
}

// Close forces closing all sockets that are alive, whether
// they're currently in use or not.
func (server *mongoServer) Close() {
	server.Lock()
	server.closed = true
	liveSockets := server.liveSockets
	unusedSockets := server.unusedSockets
	server.liveSockets = nil
	server.unusedSockets = nil
	server.Unlock()
	logf("Connections to %s closing (%d live sockets).", server.Addr, len(liveSockets))
	for i, s := range liveSockets {
		s.Close()
		liveSockets[i] = nil
	}
	for i := range unusedSockets {
		unusedSockets[i] = nil
	}
}

// RecycleSocket puts socket back into the unused cache.
func (server *mongoServer) RecycleSocket(socket *mongoSocket) {
	server.Lock()
	if !server.closed {
		server.unusedSockets = append(server.unusedSockets, socket)
	}
	server.Unlock()
}

func removeSocket(sockets []*mongoSocket, socket *mongoSocket) []*mongoSocket {
	for i, s := range sockets {
		if s == socket {
			copy(sockets[i:], sockets[i+1:])
			n := len(sockets) - 1
			sockets[n] = nil
			sockets = sockets[:n]
			break
		}
	}
	return sockets
}

// AbendSocket notifies the server that the given socket has terminated
// abnormally, and thus should be discarded rather than cached.
func (server *mongoServer) AbendSocket(socket *mongoSocket) {
	server.Lock()
	server.abended = true
	if server.closed {
		server.Unlock()
		return
	}
	server.liveSockets = removeSocket(server.liveSockets, socket)
	server.unusedSockets = removeSocket(server.unusedSockets, socket)
	server.Unlock()
	// Maybe just a timeout, but suggest a cluster sync up just in case.
	select {
	case server.sync <- true:
	default:
	}
}

func (server *mongoServer) SetInfo(info *mongoServerInfo) {
	server.Lock()
	server.info = info
	server.Unlock()
}

func (server *mongoServer) Info() *mongoServerInfo {
	server.Lock()
	info := server.info
	server.Unlock()
	return info
}

func (server *mongoServer) hasTags(serverTags []bson.D) bool {
NextTagSet:
	for _, tags := range serverTags {
	NextReqTag:
		for _, req := range tags {
			for _, has := range server.info.Tags {
				if req.Name == has.Name {
					if req.Value == has.Value {
						continue NextReqTag
					}
					continue NextTagSet
				}
			}
			continue NextTagSet
		}
		return true
	}
	return false
}

var pingDelay = 15 * time.Second

func (server *mongoServer) pinger(loop bool) {
	var delay time.Duration
	if raceDetector {
		// This variable is only ever touched by tests.
		globalMutex.Lock()
		delay = pingDelay
		globalMutex.Unlock()
	} else {
		delay = pingDelay
	}
	op := queryOp{
		collection: "admin.$cmd",
		query:      bson.D{{"ping", 1}},
		flags:      flagSlaveOk,
		limit:      -1,
	}
	for {
		if loop {
			time.Sleep(delay)
		}
		op := op
		socket, _, err := server.AcquireSocket(0, delay)
		if err == nil {
			start := time.Now()
			_, _ = socket.SimpleQuery(&op)
			delay := time.Now().Sub(start)

			server.pingWindow[server.pingIndex] = delay
			server.pingIndex = (server.pingIndex + 1) % len(server.pingWindow)
			server.pingCount++
			var max time.Duration
			for i := 0; i < len(server.pingWindow) && uint32(i) < server.pingCount; i++ {
				if server.pingWindow[i] > max {
					max = server.pingWindow[i]
				}
			}
			socket.Release()
			server.Lock()
			if server.closed {
				loop = false
			}
			server.pingValue = max
			server.Unlock()
			logf("Ping for %s is %d ms", server.Addr, max/time.Millisecond)
		} else if err == errServerClosed {
			return
		}
		if !loop {
			return
		}
	}
}

type mongoServerSlice []*mongoServer

func (s mongoServerSlice) Len() int {
	return len(s)
}

func (s mongoServerSlice) Less(i, j int) bool {
	return s[i].ResolvedAddr < s[j].ResolvedAddr
}

func (s mongoServerSlice) Swap(i, j int) {
	s[i], s[j] = s[j], s[i]
}

func (s mongoServerSlice) Sort() {
	sort.Sort(s)
}

func (s mongoServerSlice) Search(resolvedAddr string) (i int, ok bool) {
	n := len(s)
	i = sort.Search(n, func(i int) bool {
		return s[i].ResolvedAddr >= resolvedAddr
	})
	return i, i != n && s[i].ResolvedAddr == resolvedAddr
}

type mongoServers struct {
	slice mongoServerSlice
}

func (servers *mongoServers) Search(resolvedAddr string) (server *mongoServer) {
	if i, ok := servers.slice.Search(resolvedAddr); ok {
		return servers.slice[i]
	}
	return nil
}

func (servers *mongoServers) Add(server *mongoServer) {
	servers.slice = append(servers.slice, server)
	servers.slice.Sort()
}

func (servers *mongoServers) Remove(other *mongoServer) (server *mongoServer) {
	if i, found := servers.slice.Search(other.ResolvedAddr); found {
		server = servers.slice[i]
		copy(servers.slice[i:], servers.slice[i+1:])
		n := len(servers.slice) - 1
		servers.slice[n] = nil // Help GC.
		servers.slice = servers.slice[:n]
	}
	return
}

func (servers *mongoServers) Slice() []*mongoServer {
	return ([]*mongoServer)(servers.slice)
}

func (servers *mongoServers) Get(i int) *mongoServer {
	return servers.slice[i]
}

func (servers *mongoServers) Len() int {
	return len(servers.slice)
}

func (servers *mongoServers) Empty() bool {
	return len(servers.slice) == 0
}

// BestFit returns the best guess of what would be the most interesting
// server to perform operations on at this point in time.
func (servers *mongoServers) BestFit(mode Mode, serverTags []bson.D) *mongoServer {
	var best *mongoServer
	for _, next := range servers.slice {
		if best == nil {
			best = next
			best.RLock()
			if serverTags != nil && !next.info.Mongos && !best.hasTags(serverTags) {
				best.RUnlock()
				best = nil
			}
			continue
		}
		next.RLock()
		swap := false
		switch {
		case serverTags != nil && !next.info.Mongos && !next.hasTags(serverTags):
			// Must have requested tags.
		case next.info.Master != best.info.Master && mode != Nearest:
			// Prefer slaves, unless the mode is PrimaryPreferred.
			swap = (mode == PrimaryPreferred) != best.info.Master
		case absDuration(next.pingValue-best.pingValue) > 15*time.Millisecond:
			// Prefer nearest server.
			swap = next.pingValue < best.pingValue
		case len(next.liveSockets)-len(next.unusedSockets) < len(best.liveSockets)-len(best.unusedSockets):
			// Prefer servers with less connections.
			swap = true
		}
		if swap {
			best.RUnlock()
			best = next
		} else {
			next.RUnlock()
		}
	}
	if best != nil {
		best.RUnlock()
	}
	return best
}

func absDuration(d time.Duration) time.Duration {
	if d < 0 {
		return -d
	}
	return d
}