-
Notifications
You must be signed in to change notification settings - Fork 892
/
connection.go
905 lines (776 loc) · 27.6 KB
/
connection.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
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
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
// Copyright (C) MongoDB, Inc. 2017-present.
//
// 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
package topology
import (
"context"
"crypto/tls"
"errors"
"fmt"
"io"
"net"
"strings"
"sync"
"sync/atomic"
"time"
"go.mongodb.org/mongo-driver/internal/csot"
"go.mongodb.org/mongo-driver/mongo/address"
"go.mongodb.org/mongo-driver/mongo/description"
"go.mongodb.org/mongo-driver/x/bsonx/bsoncore"
"go.mongodb.org/mongo-driver/x/mongo/driver"
"go.mongodb.org/mongo-driver/x/mongo/driver/ocsp"
"go.mongodb.org/mongo-driver/x/mongo/driver/wiremessage"
)
// Connection state constants.
const (
connDisconnected int64 = iota
connConnected
connInitialized
)
var globalConnectionID uint64 = 1
var (
defaultMaxMessageSize uint32 = 48000000
errResponseTooLarge = errors.New("length of read message too large")
errLoadBalancedStateMismatch = errors.New("driver attempted to initialize in load balancing mode, but the server does not support this mode")
)
func nextConnectionID() uint64 { return atomic.AddUint64(&globalConnectionID, 1) }
type connection struct {
// state must be accessed using the atomic package and should be at the beginning of the struct.
// - atomic bug: https://pkg.go.dev/sync/atomic#pkg-note-BUG
// - suggested layout: https://go101.org/article/memory-layout.html
state int64
id string
nc net.Conn // When nil, the connection is closed.
addr address.Address
idleTimeout time.Duration
idleDeadline atomic.Value // Stores a time.Time
readTimeout time.Duration
writeTimeout time.Duration
desc description.Server
helloRTT time.Duration
compressor wiremessage.CompressorID
zliblevel int
zstdLevel int
connectDone chan struct{}
config *connectionConfig
cancelConnectContext context.CancelFunc
connectContextMade chan struct{}
canStream bool
currentlyStreaming bool
connectContextMutex sync.Mutex
cancellationListener cancellationListener
serverConnectionID *int64 // the server's ID for this client's connection
// pool related fields
pool *pool
// TODO(GODRIVER-2824): change driverConnectionID type to int64.
driverConnectionID uint64
generation uint64
// awaitingResponse indicates that the server response was not completely
// read before returning the connection to the pool.
awaitingResponse bool
}
// newConnection handles the creation of a connection. It does not connect the connection.
func newConnection(addr address.Address, opts ...ConnectionOption) *connection {
cfg := newConnectionConfig(opts...)
id := fmt.Sprintf("%s[-%d]", addr, nextConnectionID())
c := &connection{
id: id,
addr: addr,
idleTimeout: cfg.idleTimeout,
readTimeout: cfg.readTimeout,
writeTimeout: cfg.writeTimeout,
connectDone: make(chan struct{}),
config: cfg,
connectContextMade: make(chan struct{}),
cancellationListener: newCancellListener(),
}
// Connections to non-load balanced deployments should eagerly set the generation numbers so errors encountered
// at any point during connection establishment can be processed without the connection being considered stale.
if !c.config.loadBalanced {
c.setGenerationNumber()
}
atomic.StoreInt64(&c.state, connInitialized)
return c
}
// DriverConnectionID returns the driver connection ID.
// TODO(GODRIVER-2824): change return type to int64.
func (c *connection) DriverConnectionID() uint64 {
return c.driverConnectionID
}
// setGenerationNumber sets the connection's generation number if a callback has been provided to do so in connection
// configuration.
func (c *connection) setGenerationNumber() {
if c.config.getGenerationFn != nil {
c.generation = c.config.getGenerationFn(c.desc.ServiceID)
}
}
// hasGenerationNumber returns true if the connection has set its generation number. If so, this indicates that the
// generationNumberFn provided via the connection options has been called exactly once.
func (c *connection) hasGenerationNumber() bool {
if !c.config.loadBalanced {
// The generation is known for all non-LB clusters once the connection object has been created.
return true
}
// For LB clusters, we set the generation after the initial handshake, so we know it's set if the connection
// description has been updated to reflect that it's behind an LB.
return c.desc.LoadBalanced()
}
// connect handles the I/O for a connection. It will dial, configure TLS, and perform initialization
// handshakes. All errors returned by connect are considered "before the handshake completes" and
// must be handled by calling the appropriate SDAM handshake error handler.
func (c *connection) connect(ctx context.Context) (err error) {
if !atomic.CompareAndSwapInt64(&c.state, connInitialized, connConnected) {
return nil
}
defer close(c.connectDone)
// If connect returns an error, set the connection status as disconnected and close the
// underlying net.Conn if it was created.
defer func() {
if err != nil {
atomic.StoreInt64(&c.state, connDisconnected)
if c.nc != nil {
_ = c.nc.Close()
}
}
}()
// Create separate contexts for dialing a connection and doing the MongoDB/auth handshakes.
//
// handshakeCtx is simply a cancellable version of ctx because there's no default timeout that needs to be applied
// to the full handshake. The cancellation allows consumers to bail out early when dialing a connection if it's no
// longer required. This is done in lock because it accesses the shared cancelConnectContext field.
//
// dialCtx is equal to handshakeCtx if connectTimeoutMS=0. Otherwise, it is derived from handshakeCtx so the
// cancellation still applies but with an added timeout to ensure the connectTimeoutMS option is applied to socket
// establishment and the TLS handshake as a whole. This is created outside of the connectContextMutex lock to avoid
// holding the lock longer than necessary.
c.connectContextMutex.Lock()
var handshakeCtx context.Context
handshakeCtx, c.cancelConnectContext = context.WithCancel(ctx)
c.connectContextMutex.Unlock()
dialCtx := handshakeCtx
var dialCancel context.CancelFunc
if c.config.connectTimeout != 0 {
dialCtx, dialCancel = context.WithTimeout(handshakeCtx, c.config.connectTimeout)
defer dialCancel()
}
defer func() {
var cancelFn context.CancelFunc
c.connectContextMutex.Lock()
cancelFn = c.cancelConnectContext
c.cancelConnectContext = nil
c.connectContextMutex.Unlock()
if cancelFn != nil {
cancelFn()
}
}()
close(c.connectContextMade)
// Assign the result of DialContext to a temporary net.Conn to ensure that c.nc is not set in an error case.
tempNc, err := c.config.dialer.DialContext(dialCtx, c.addr.Network(), c.addr.String())
if err != nil {
return ConnectionError{Wrapped: err, init: true}
}
c.nc = tempNc
if c.config.tlsConfig != nil {
tlsConfig := c.config.tlsConfig.Clone()
// store the result of configureTLS in a separate variable than c.nc to avoid overwriting c.nc with nil in
// error cases.
ocspOpts := &ocsp.VerifyOptions{
Cache: c.config.ocspCache,
DisableEndpointChecking: c.config.disableOCSPEndpointCheck,
HTTPClient: c.config.httpClient,
}
tlsNc, err := configureTLS(dialCtx, c.config.tlsConnectionSource, c.nc, c.addr, tlsConfig, ocspOpts)
if err != nil {
return ConnectionError{Wrapped: err, init: true}
}
c.nc = tlsNc
}
// running hello and authentication is handled by a handshaker on the configuration instance.
handshaker := c.config.handshaker
if handshaker == nil {
return nil
}
var handshakeInfo driver.HandshakeInformation
handshakeStartTime := time.Now()
handshakeConn := initConnection{c}
handshakeInfo, err = handshaker.GetHandshakeInformation(handshakeCtx, c.addr, handshakeConn)
if err == nil {
// We only need to retain the Description field as the connection's description. The authentication-related
// fields in handshakeInfo are tracked by the handshaker if necessary.
c.desc = handshakeInfo.Description
c.serverConnectionID = handshakeInfo.ServerConnectionID
c.helloRTT = time.Since(handshakeStartTime)
// If the application has indicated that the cluster is load balanced, ensure the server has included serviceId
// in its handshake response to signal that it knows it's behind an LB as well.
if c.config.loadBalanced && c.desc.ServiceID == nil {
err = errLoadBalancedStateMismatch
}
}
if err == nil {
// For load-balanced connections, the generation number depends on the service ID, which isn't known until the
// initial MongoDB handshake is done. To account for this, we don't attempt to set the connection's generation
// number unless GetHandshakeInformation succeeds.
if c.config.loadBalanced {
c.setGenerationNumber()
}
// If we successfully finished the first part of the handshake and verified LB state, continue with the rest of
// the handshake.
err = handshaker.FinishHandshake(handshakeCtx, handshakeConn)
}
// We have a failed handshake here
if err != nil {
return ConnectionError{Wrapped: err, init: true}
}
if len(c.desc.Compression) > 0 {
clientMethodLoop:
for _, method := range c.config.compressors {
for _, serverMethod := range c.desc.Compression {
if method != serverMethod {
continue
}
switch strings.ToLower(method) {
case "snappy":
c.compressor = wiremessage.CompressorSnappy
case "zlib":
c.compressor = wiremessage.CompressorZLib
c.zliblevel = wiremessage.DefaultZlibLevel
if c.config.zlibLevel != nil {
c.zliblevel = *c.config.zlibLevel
}
case "zstd":
c.compressor = wiremessage.CompressorZstd
c.zstdLevel = wiremessage.DefaultZstdLevel
if c.config.zstdLevel != nil {
c.zstdLevel = *c.config.zstdLevel
}
}
break clientMethodLoop
}
}
}
return nil
}
func (c *connection) wait() {
if c.connectDone != nil {
<-c.connectDone
}
}
func (c *connection) closeConnectContext() {
<-c.connectContextMade
var cancelFn context.CancelFunc
c.connectContextMutex.Lock()
cancelFn = c.cancelConnectContext
c.cancelConnectContext = nil
c.connectContextMutex.Unlock()
if cancelFn != nil {
cancelFn()
}
}
func transformNetworkError(ctx context.Context, originalError error, contextDeadlineUsed bool) error {
if originalError == nil {
return nil
}
// If there was an error and the context was cancelled, we assume it happened due to the cancellation.
if errors.Is(ctx.Err(), context.Canceled) {
return ctx.Err()
}
// If there was a timeout error and the context deadline was used, we convert the error into
// context.DeadlineExceeded.
if !contextDeadlineUsed {
return originalError
}
if netErr, ok := originalError.(net.Error); ok && netErr.Timeout() {
return fmt.Errorf("%w: %s", context.DeadlineExceeded, originalError.Error())
}
return originalError
}
func (c *connection) cancellationListenerCallback() {
_ = c.close()
}
func (c *connection) writeWireMessage(ctx context.Context, wm []byte) error {
var err error
if atomic.LoadInt64(&c.state) != connConnected {
return ConnectionError{
ConnectionID: c.id,
message: "connection is closed",
}
}
var deadline time.Time
if c.writeTimeout != 0 {
deadline = time.Now().Add(c.writeTimeout)
}
var contextDeadlineUsed bool
if dl, ok := ctx.Deadline(); ok && (deadline.IsZero() || dl.Before(deadline)) {
contextDeadlineUsed = true
deadline = dl
}
if err := c.nc.SetWriteDeadline(deadline); err != nil {
return ConnectionError{ConnectionID: c.id, Wrapped: err, message: "failed to set write deadline"}
}
err = c.write(ctx, wm)
if err != nil {
c.close()
return ConnectionError{
ConnectionID: c.id,
Wrapped: transformNetworkError(ctx, err, contextDeadlineUsed),
message: "unable to write wire message to network",
}
}
return nil
}
func (c *connection) write(ctx context.Context, wm []byte) (err error) {
go c.cancellationListener.Listen(ctx, c.cancellationListenerCallback)
defer func() {
// There is a race condition between Write and StopListening. If the context is cancelled after c.nc.Write
// succeeds, the cancellation listener could fire and close the connection. In this case, the connection has
// been invalidated but the error is nil. To account for this, overwrite the error to context.Cancelled if
// the abortedForCancellation flag was set.
if aborted := c.cancellationListener.StopListening(); aborted && err == nil {
err = context.Canceled
}
}()
_, err = c.nc.Write(wm)
return err
}
// readWireMessage reads a wiremessage from the connection. The dst parameter will be overwritten.
func (c *connection) readWireMessage(ctx context.Context) ([]byte, error) {
if atomic.LoadInt64(&c.state) != connConnected {
return nil, ConnectionError{
ConnectionID: c.id,
message: "connection is closed",
}
}
var deadline time.Time
if c.readTimeout != 0 {
deadline = time.Now().Add(c.readTimeout)
}
var contextDeadlineUsed bool
if dl, ok := ctx.Deadline(); ok && (deadline.IsZero() || dl.Before(deadline)) {
contextDeadlineUsed = true
deadline = dl
}
if err := c.nc.SetReadDeadline(deadline); err != nil {
return nil, ConnectionError{ConnectionID: c.id, Wrapped: err, message: "failed to set read deadline"}
}
dst, errMsg, err := c.read(ctx)
if err != nil {
if nerr := net.Error(nil); errors.As(err, &nerr) && nerr.Timeout() && csot.IsTimeoutContext(ctx) {
// If the error was a timeout error and CSOT is enabled, instead of
// closing the connection mark it as awaiting response so the pool
// can read the response before making it available to other
// operations.
c.awaitingResponse = true
} else {
// Otherwise, use the pre-CSOT behavior and close the connection
// because we don't know if there are other bytes left to read.
c.close()
}
message := errMsg
if errors.Is(err, io.EOF) {
message = "socket was unexpectedly closed"
}
return nil, ConnectionError{
ConnectionID: c.id,
Wrapped: transformNetworkError(ctx, err, contextDeadlineUsed),
message: message,
}
}
return dst, nil
}
func (c *connection) read(ctx context.Context) (bytesRead []byte, errMsg string, err error) {
go c.cancellationListener.Listen(ctx, c.cancellationListenerCallback)
defer func() {
// If the context is cancelled after we finish reading the server response, the cancellation listener could fire
// even though the socket reads succeed. To account for this, we overwrite err to be context.Canceled if the
// abortedForCancellation flag is set.
if aborted := c.cancellationListener.StopListening(); aborted && err == nil {
errMsg = "unable to read server response"
err = context.Canceled
}
}()
// We use an array here because it only costs 4 bytes on the stack and means we'll only need to
// reslice dst once instead of twice.
var sizeBuf [4]byte
// We do a ReadFull into an array here instead of doing an opportunistic ReadAtLeast into dst
// because there might be more than one wire message waiting to be read, for example when
// reading messages from an exhaust cursor.
_, err = io.ReadFull(c.nc, sizeBuf[:])
if err != nil {
return nil, "incomplete read of message header", err
}
// read the length as an int32
size := (int32(sizeBuf[0])) | (int32(sizeBuf[1]) << 8) | (int32(sizeBuf[2]) << 16) | (int32(sizeBuf[3]) << 24)
// In the case of a hello response where MaxMessageSize has not yet been set, use the hard-coded
// defaultMaxMessageSize instead.
maxMessageSize := c.desc.MaxMessageSize
if maxMessageSize == 0 {
maxMessageSize = defaultMaxMessageSize
}
if uint32(size) > maxMessageSize {
return nil, errResponseTooLarge.Error(), errResponseTooLarge
}
dst := make([]byte, size)
copy(dst, sizeBuf[:])
_, err = io.ReadFull(c.nc, dst[4:])
if err != nil {
return dst, "incomplete read of full message", err
}
return dst, "", nil
}
func (c *connection) close() error {
// Overwrite the connection state as the first step so only the first close call will execute.
if !atomic.CompareAndSwapInt64(&c.state, connConnected, connDisconnected) {
return nil
}
var err error
if c.nc != nil {
err = c.nc.Close()
}
return err
}
func (c *connection) closed() bool {
return atomic.LoadInt64(&c.state) == connDisconnected
}
func (c *connection) idleTimeoutExpired() bool {
now := time.Now()
if c.idleTimeout > 0 {
idleDeadline, ok := c.idleDeadline.Load().(time.Time)
if ok && now.After(idleDeadline) {
return true
}
}
return false
}
func (c *connection) bumpIdleDeadline() {
if c.idleTimeout > 0 {
c.idleDeadline.Store(time.Now().Add(c.idleTimeout))
}
}
func (c *connection) setCanStream(canStream bool) {
c.canStream = canStream
}
func (c initConnection) supportsStreaming() bool {
return c.canStream
}
func (c *connection) setStreaming(streaming bool) {
c.currentlyStreaming = streaming
}
func (c *connection) getCurrentlyStreaming() bool {
return c.currentlyStreaming
}
func (c *connection) setSocketTimeout(timeout time.Duration) {
c.readTimeout = timeout
c.writeTimeout = timeout
}
func (c *connection) ID() string {
return c.id
}
func (c *connection) ServerConnectionID() *int64 {
return c.serverConnectionID
}
// initConnection is an adapter used during connection initialization. It has the minimum
// functionality necessary to implement the driver.Connection interface, which is required to pass a
// *connection to a Handshaker.
type initConnection struct{ *connection }
var _ driver.Connection = initConnection{}
var _ driver.StreamerConnection = initConnection{}
func (c initConnection) Description() description.Server {
if c.connection == nil {
return description.Server{}
}
return c.connection.desc
}
func (c initConnection) Close() error { return nil }
func (c initConnection) ID() string { return c.id }
func (c initConnection) Address() address.Address { return c.addr }
func (c initConnection) Stale() bool { return false }
func (c initConnection) LocalAddress() address.Address {
if c.connection == nil || c.nc == nil {
return address.Address("0.0.0.0")
}
return address.Address(c.nc.LocalAddr().String())
}
func (c initConnection) WriteWireMessage(ctx context.Context, wm []byte) error {
return c.writeWireMessage(ctx, wm)
}
func (c initConnection) ReadWireMessage(ctx context.Context) ([]byte, error) {
return c.readWireMessage(ctx)
}
func (c initConnection) SetStreaming(streaming bool) {
c.setStreaming(streaming)
}
func (c initConnection) CurrentlyStreaming() bool {
return c.getCurrentlyStreaming()
}
func (c initConnection) SupportsStreaming() bool {
return c.supportsStreaming()
}
// Connection implements the driver.Connection interface to allow reading and writing wire
// messages and the driver.Expirable interface to allow expiring. It wraps an underlying
// topology.connection to make it more goroutine-safe and nil-safe.
type Connection struct {
connection *connection
refCount int
cleanupPoolFn func()
// cleanupServerFn resets the server state when a connection is returned to the connection pool
// via Close() or expired via Expire().
cleanupServerFn func()
mu sync.RWMutex
}
var _ driver.Connection = (*Connection)(nil)
var _ driver.Expirable = (*Connection)(nil)
var _ driver.PinnedConnection = (*Connection)(nil)
// WriteWireMessage handles writing a wire message to the underlying connection.
func (c *Connection) WriteWireMessage(ctx context.Context, wm []byte) error {
c.mu.RLock()
defer c.mu.RUnlock()
if c.connection == nil {
return ErrConnectionClosed
}
return c.connection.writeWireMessage(ctx, wm)
}
// ReadWireMessage handles reading a wire message from the underlying connection. The dst parameter
// will be overwritten with the new wire message.
func (c *Connection) ReadWireMessage(ctx context.Context) ([]byte, error) {
c.mu.RLock()
defer c.mu.RUnlock()
if c.connection == nil {
return nil, ErrConnectionClosed
}
return c.connection.readWireMessage(ctx)
}
// CompressWireMessage handles compressing the provided wire message using the underlying
// connection's compressor. The dst parameter will be overwritten with the new wire message. If
// there is no compressor set on the underlying connection, then no compression will be performed.
func (c *Connection) CompressWireMessage(src, dst []byte) ([]byte, error) {
c.mu.RLock()
defer c.mu.RUnlock()
if c.connection == nil {
return dst, ErrConnectionClosed
}
if c.connection.compressor == wiremessage.CompressorNoOp {
return append(dst, src...), nil
}
_, reqid, respto, origcode, rem, ok := wiremessage.ReadHeader(src)
if !ok {
return dst, errors.New("wiremessage is too short to compress, less than 16 bytes")
}
idx, dst := wiremessage.AppendHeaderStart(dst, reqid, respto, wiremessage.OpCompressed)
dst = wiremessage.AppendCompressedOriginalOpCode(dst, origcode)
dst = wiremessage.AppendCompressedUncompressedSize(dst, int32(len(rem)))
dst = wiremessage.AppendCompressedCompressorID(dst, c.connection.compressor)
opts := driver.CompressionOpts{
Compressor: c.connection.compressor,
ZlibLevel: c.connection.zliblevel,
ZstdLevel: c.connection.zstdLevel,
}
compressed, err := driver.CompressPayload(rem, opts)
if err != nil {
return nil, err
}
dst = wiremessage.AppendCompressedCompressedMessage(dst, compressed)
return bsoncore.UpdateLength(dst, idx, int32(len(dst[idx:]))), nil
}
// Description returns the server description of the server this connection is connected to.
func (c *Connection) Description() description.Server {
c.mu.RLock()
defer c.mu.RUnlock()
if c.connection == nil {
return description.Server{}
}
return c.connection.desc
}
// Close returns this connection to the connection pool. This method may not closeConnection the underlying
// socket.
func (c *Connection) Close() error {
c.mu.Lock()
defer c.mu.Unlock()
if c.connection == nil || c.refCount > 0 {
return nil
}
return c.cleanupReferences()
}
// Expire closes this connection and will closeConnection the underlying socket.
func (c *Connection) Expire() error {
c.mu.Lock()
defer c.mu.Unlock()
if c.connection == nil {
return nil
}
_ = c.connection.close()
return c.cleanupReferences()
}
func (c *Connection) cleanupReferences() error {
err := c.connection.pool.checkIn(c.connection)
if c.cleanupPoolFn != nil {
c.cleanupPoolFn()
c.cleanupPoolFn = nil
}
if c.cleanupServerFn != nil {
c.cleanupServerFn()
c.cleanupServerFn = nil
}
c.connection = nil
return err
}
// Alive returns if the connection is still alive.
func (c *Connection) Alive() bool {
return c.connection != nil
}
// ID returns the ID of this connection.
func (c *Connection) ID() string {
c.mu.RLock()
defer c.mu.RUnlock()
if c.connection == nil {
return "<closed>"
}
return c.connection.id
}
// ServerConnectionID returns the server connection ID of this connection.
func (c *Connection) ServerConnectionID() *int64 {
if c.connection == nil {
return nil
}
return c.connection.serverConnectionID
}
// Stale returns if the connection is stale.
func (c *Connection) Stale() bool {
c.mu.RLock()
defer c.mu.RUnlock()
return c.connection.pool.stale(c.connection)
}
// Address returns the address of this connection.
func (c *Connection) Address() address.Address {
c.mu.RLock()
defer c.mu.RUnlock()
if c.connection == nil {
return address.Address("0.0.0.0")
}
return c.connection.addr
}
// LocalAddress returns the local address of the connection
func (c *Connection) LocalAddress() address.Address {
c.mu.RLock()
defer c.mu.RUnlock()
if c.connection == nil || c.connection.nc == nil {
return address.Address("0.0.0.0")
}
return address.Address(c.connection.nc.LocalAddr().String())
}
// PinToCursor updates this connection to reflect that it is pinned to a cursor.
func (c *Connection) PinToCursor() error {
return c.pin("cursor", c.connection.pool.pinConnectionToCursor, c.connection.pool.unpinConnectionFromCursor)
}
// PinToTransaction updates this connection to reflect that it is pinned to a transaction.
func (c *Connection) PinToTransaction() error {
return c.pin("transaction", c.connection.pool.pinConnectionToTransaction, c.connection.pool.unpinConnectionFromTransaction)
}
func (c *Connection) pin(reason string, updatePoolFn, cleanupPoolFn func()) error {
c.mu.Lock()
defer c.mu.Unlock()
if c.connection == nil {
return fmt.Errorf("attempted to pin a connection for a %s, but the connection has already been returned to the pool", reason)
}
// Only use the provided callbacks for the first reference to avoid double-counting pinned connection statistics
// in the pool.
if c.refCount == 0 {
updatePoolFn()
c.cleanupPoolFn = cleanupPoolFn
}
c.refCount++
return nil
}
// UnpinFromCursor updates this connection to reflect that it is no longer pinned to a cursor.
func (c *Connection) UnpinFromCursor() error {
return c.unpin("cursor")
}
// UnpinFromTransaction updates this connection to reflect that it is no longer pinned to a transaction.
func (c *Connection) UnpinFromTransaction() error {
return c.unpin("transaction")
}
func (c *Connection) unpin(reason string) error {
c.mu.Lock()
defer c.mu.Unlock()
if c.connection == nil {
// We don't error here because the resource could have been forcefully closed via Expire.
return nil
}
if c.refCount == 0 {
return fmt.Errorf("attempted to unpin a connection from a %s, but the connection is not pinned by any resources", reason)
}
c.refCount--
return nil
}
// DriverConnectionID returns the driver connection ID.
// TODO(GODRIVER-2824): change return type to int64.
func (c *Connection) DriverConnectionID() uint64 {
return c.connection.DriverConnectionID()
}
func configureTLS(ctx context.Context,
tlsConnSource tlsConnectionSource,
nc net.Conn,
addr address.Address,
config *tls.Config,
ocspOpts *ocsp.VerifyOptions,
) (net.Conn, error) {
// Ensure config.ServerName is always set for SNI.
if config.ServerName == "" {
hostname := addr.String()
colonPos := strings.LastIndex(hostname, ":")
if colonPos == -1 {
colonPos = len(hostname)
}
hostname = hostname[:colonPos]
config.ServerName = hostname
}
client := tlsConnSource.Client(nc, config)
if err := clientHandshake(ctx, client); err != nil {
return nil, err
}
// Only do OCSP verification if TLS verification is requested.
if !config.InsecureSkipVerify {
if ocspErr := ocsp.Verify(ctx, client.ConnectionState(), ocspOpts); ocspErr != nil {
return nil, ocspErr
}
}
return client, nil
}
// TODO: Naming?
// cancellListener listens for context cancellation and notifies listeners via a
// callback function.
type cancellListener struct {
aborted bool
done chan struct{}
}
// newCancellListener constructs a cancellListener.
func newCancellListener() *cancellListener {
return &cancellListener{
done: make(chan struct{}),
}
}
// Listen blocks until the provided context is cancelled or listening is aborted
// via the StopListening function. If this detects that the context has been
// cancelled (i.e. errors.Is(ctx.Err(), context.Canceled), the provided callback is
// called to abort in-progress work. Even if the context expires, this function
// will block until StopListening is called.
func (c *cancellListener) Listen(ctx context.Context, abortFn func()) {
c.aborted = false
select {
case <-ctx.Done():
if errors.Is(ctx.Err(), context.Canceled) {
c.aborted = true
abortFn()
}
<-c.done
case <-c.done:
}
}
// StopListening stops the in-progress Listen call. This blocks if there is no
// in-progress Listen call. This function will return true if the provided abort
// callback was called when listening for cancellation on the previous context.
func (c *cancellListener) StopListening() bool {
c.done <- struct{}{}
return c.aborted
}