/
Client.pm6
683 lines (526 loc) · 20.2 KB
/
Client.pm6
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
use v6;
#TODO readconcern does not have to be a BSON::Document. no encoding!
#-------------------------------------------------------------------------------
unit package MongoDB:auth<github:MARTIMM>;
use MongoDB;
use MongoDB::Uri;
use MongoDB::Server;
use MongoDB::Database;
use MongoDB::Collection;
use BSON::Document;
use Semaphore::ReadersWriters;
#-------------------------------------------------------------------------------
class Client {
# topology-set is used to block the server-select() process when topology
# still needs to be calculated.
has TopologyType $!topology-type;
has TopologyType $!user-request-topology;
has Bool $!topology-set;
# Store all found servers here. key is the name of the server which is
# the server address/ip and its port number. This should be unique.
has Hash $!servers;
has Array $!todo-servers;
has Semaphore::ReadersWriters $!rw-sem;
has Str $!uri;
has MongoDB::Uri $.uri-obj;
#has Str $!replicaset;
has Promise $!background-discovery;
has Bool $!repeat-discovery-loop;
# Only for single threaded implementations according to mongodb documents
# has Bool $!server-selection-try-once = False;
# has Int $!socket-check-interval-ms = 5000;
# Cleaning up is done concurrently so the test on a variable like $!servers
# to be undefined, will not work. Instead check if the below variable is True
# to see if destroying the client is started.
has Bool $!cleanup-started = False;
#-----------------------------------------------------------------------------
method new ( |c ) {
# In case of an assignement like $c .= new(...) $c should be cleaned first
if self.defined and not $!cleanup-started {
warn-message('user client object still defined, will be cleaned first');
self.cleanup;
}
MongoDB::Client.bless(|c);
}
#-----------------------------------------------------------------------------
#TODO pod doc arguments
submethod BUILD ( Str:D :$uri
# TopologyType :$topology-type = TT-Unknown,
# Int :$!idle-write-period-ms = 10_000,
) {
# $!user-request-topology = $topology-type;
$!topology-type = TT-NotSet;
$!topology-set = False;
$!servers = {};
$!todo-servers = [];
# Initialize mutexes
$!rw-sem .= new;
# $!rw-sem.debug = True;
$!rw-sem.add-mutex-names(
<servers todo topology>, :RWPatternType(C-RW-WRITERPRIO)
);
# Parse the uri and get info in $!uri-obj. Fields are protocol, username,
# password, servers, database and options.
$!uri = $uri;
$!uri-obj .= new(:$!uri);
debug-message("found {$!uri-obj.servers.elems} servers in uri");
# Setup todo list with servers to be processed, Safety net not needed yet
# because threads are not started.
for @($!uri-obj.servers) -> Hash $server {
debug-message("todo: $server<host>:$server<port>");
$!todo-servers.push("$server<host>:$server<port>");
}
# Background proces to handle server monitoring data
$!background-discovery = Promise.start( {
# counter to check if there are new servers added. if so, the counter
# is set to 0. if less then 5 the sleeptime is about a second. When
# count reaches max, the thread is stopped.
my Int $changes-count = 0;
# Used in debug message
my Instant $t0 = now;
$!repeat-discovery-loop = True;
repeat {
# count to some limit when no servers are found then stop. if a
# server is found, count is reset.
$changes-count = self!discover-servers ?? 0 !! $changes-count + 1;
# When there is no work take a nap! This sleeping period is the
# moment we do not process the todo list.
if $changes-count < 7 {
sleep 1.4;
}
else {
# stop the loop and exit thread. for new changes, discover-servers()
# is called later via select-server().
$!repeat-discovery-loop = False;
}
CATCH {
default {
# Keep this .note in. It helps debugging when an error takes place
# The error will not be seen before the result of Promise is read
.note;
.rethrow;
}
}
debug-message(
"one client processing cycle done after " ~
((now - $t0) * 1000).fmt('%.3f') ~ " ms"
);
} while $!repeat-discovery-loop;
debug-message("server discovery loop stopped");
'normal end of service'
} # block
); # start
} # method
#-----------------------------------------------------------------------------
method process-topology ( ) {
$!rw-sem.writer( 'topology', { $!topology-set = False; });
#TODO take user topology request into account
# Calculate topology. Upon startup, the topology is set to
# TT-Unknown. Here, the real value is calculated and set. Doing
# it repeatedly it will be able to change dynamicaly.
#
my TopologyType $topology = TT-Unknown;
my Hash $servers = $!rw-sem.reader( 'servers', {%($!servers.kv;)});
my Int $servers-count = 0;
my Bool $found-standalone = False;
my Bool $found-sharded = False;
my Bool $found-replica = False;
for $servers.keys -> $server-name {
my ServerStatus $status =
$servers{$server-name}.get-status<status> // SS-Unknown;
trace-message("status: $server-name, $status");
given $status {
when SS-Standalone {
$servers-count++;
if $found-standalone or $found-sharded or $found-replica {
# cannot have more than one standalone servers
$topology = TT-Unknown;
}
else {
$found-standalone = True;
$topology = TT-Single;
}
}
when SS-Mongos {
$servers-count++;
if $found-standalone or $found-replica {
# cannot have other than shard servers
$topology = TT-Unknown;
}
else {
$found-sharded = True;
$topology = TT-Sharded;
}
}
#TODO test same set of replicasets -> otherwise also TT-Unknown
when SS-RSPrimary {
$servers-count++;
if $found-standalone or $found-sharded {
# cannot have other than replica servers
$topology = TT-Unknown;
}
else {
$found-replica = True;
$topology = TT-ReplicaSetWithPrimary;
}
}
when any( SS-RSSecondary, SS-RSArbiter, SS-RSOther, SS-RSGhost ) {
$servers-count++;
if $found-standalone or $found-sharded {
# cannot have other than replica servers
$topology = TT-Unknown;
}
else {
$found-replica = True;
$topology = TT-ReplicaSetNoPrimary
unless $topology ~~ TT-ReplicaSetWithPrimary;
}
}
when SS-NotSet {
# When status of a server is not yet set, stop the calculation and
# wait for next round
$topology = TT-NotSet;
last;
} # when SS-NotSet
} # given $status
} # for $servers.keys -> $server-name
# One of the servers is not ready yet
if $topology !~~ TT-NotSet {
if $servers-count == 1 and $!uri-obj.options<replicaSet>:!exists {
$topology = TT-Single;
}
$!rw-sem.writer( 'topology', {
$!topology-type = $topology;
$!topology-set = True;
}
);
}
info-message("client topology is $topology");
}
#-----------------------------------------------------------------------------
# Return number of servers
method nbr-servers ( --> Int ) {
self!check-discovery-process;
$!rw-sem.reader( 'servers', {$!servers.elems;});
}
#-----------------------------------------------------------------------------
# Get the server status
method server-status ( Str:D $server-name --> ServerStatus ) {
self!check-discovery-process;
#! Wait until topology is set
until $!rw-sem.reader( 'topology', { $!topology-set }) { sleep 0.5; }
my Hash $h = $!rw-sem.reader(
'servers', {
my $x = $!servers{$server-name}:exists
?? $!servers{$server-name}.get-status
!! {};
$x;
});
my ServerStatus $sts = $h<status> // SS-Unknown;
debug-message("server-status: '$server-name', $sts");
$sts;
}
#-----------------------------------------------------------------------------
# Get the server version
method server-version ( Str:D $server-name --> Str ) {
self!check-discovery-process;
#! Wait until topology is set
until $!rw-sem.reader( 'topology', { $!topology-set }) { sleep 0.5; }
my BSON::Document $ss = $!rw-sem.reader(
'servers', {
my $x = $!servers{$server-name}:exists
?? $!servers{$server-name}.server-state-info
!! {};
$x;
});
my Str $server-version = $ss<version>;
debug-message("server version: $server-version");
$server-version;
}
#-----------------------------------------------------------------------------
method topology ( --> TopologyType ) {
#! Wait until topology is set
until $!rw-sem.reader( 'topology', { $!topology-set }) {
sleep 0.5;
}
$!rw-sem.reader( 'topology', {$!topology-type});
}
#-----------------------------------------------------------------------------
# Selecting servers based on;
#
# - Record the server selection start time
# - If the topology wire version is invalid, raise an error
# - Find suitable servers by topology type and operation type
# - If there are any suitable servers, choose one at random from those within
# the latency window and return it; otherwise, continue to step #5
# - Request an immediate topology check, then block the server selection
# thread until the topology changes or until the server selection timeout
# has elapsed
# - If more than serverSelectionTimeoutMS milliseconds have elapsed since the
# selection start time, raise a server selection error
# - Goto Step #2
#-----------------------------------------------------------------------------
#-----------------------------------------------------------------------------
# Request specific servername
multi method select-server ( Str:D :$servername! --> MongoDB::Server ) {
self.process-topology;
# record the server selection start time. used also in debug message
my Instant $t0 = now;
my MongoDB::Server $selected-server;
# find suitable servers by topology type and operation type
repeat {
self!check-discovery-process;
#! Wait until topology is set
until $!rw-sem.reader( 'topology', { $!topology-set }) {
sleep 0.5;
}
$selected-server = $!rw-sem.reader( 'servers', {
#note "Servers: ", $!servers.keys;
#note "Request: $selected-server.name()";
$!servers{$servername}:exists
?? $!servers{$servername}
!! MongoDB::Server;
}
);
last if ? $selected-server;
sleep $!uri-obj.options<heartbeatFrequencyMS> / 1000.0;
} while ((now - $t0) * 1000) < $!uri-obj.options<serverSelectionTimeoutMS>;
debug-message("searched for {((now - $t0) * 1000).fmt('%.3f')} ms");
if ?$selected-server {
debug-message("server '$selected-server.name()' selected");
}
else {
warn-message("no suitable server selected");
}
$selected-server;
}
#TODO pod doc
#TODO use read/write concern for selection
#TODO must break loop when nothing is found
#-----------------------------------------------------------------------------
# Read/write concern selection
multi method select-server ( --> MongoDB::Server ) {
self.process-topology;
my MongoDB::Server $selected-server;
# record the server selection start time. used also in debug message
my Instant $t0 = now;
#! Wait until topology is set
until $!rw-sem.reader( 'topology', { $!topology-set }) {
sleep 0.5;
}
# find suitable servers by topology type and operation type
repeat {
my MongoDB::Server @selected-servers = ();
my Hash $servers = $!rw-sem.reader( 'servers', {$!servers.clone});
my TopologyType $topology =
$!rw-sem.reader( 'topology', {$!topology-type});
trace-message("topology: $topology");
given $topology {
when TT-Single {
for $servers.keys -> $sname {
$selected-server = $servers{$sname};
my Hash $sdata = $selected-server.get-status;
last if $sdata<status> ~~ SS-Standalone;
}
}
when TT-ReplicaSetWithPrimary {
#TODO check replica set option in uri
for $servers.keys -> $sname {
$selected-server = $servers{$sname};
my Hash $sdata = $selected-server.get-status;
last if $sdata<status> ~~ SS-RSPrimary;
}
}
when TT-ReplicaSetNoPrimary {
#TODO check replica set option in uri if SS-RSSecondary
for $servers.keys -> $sname {
my $s = $servers{$sname};
my Hash $sdata = $s.get-status;
@selected-servers.push: $s if $sdata<status> ~~ SS-RSSecondary;
}
}
when TT-Sharded {
for $servers.keys -> $sname {
my $s = $servers{$sname};
my Hash $sdata = $s.get-status;
@selected-servers.push: $s if $sdata<status> ~~ SS-Mongos;
}
}
}
# if no server selected but there are some in the array
if $topology !~~ TT-Unknown and !$selected-server and +@selected-servers {
# if only one server in array, take that one
if @selected-servers.elems == 1 {
$selected-server = @selected-servers.pop;
}
# now w're getting complex because we need to select from a number
# of suitable servers.
else {
my Array $slctd-svrs = [];
my Duration $min-rtt-ms .= new(1_000_000_000);
# get minimum rtt from server measurements
for @selected-servers -> MongoDB::Server $svr {
my Hash $svr-sts = $svr.get-status;
$min-rtt-ms = $svr-sts<weighted-mean-rtt-ms>
if $min-rtt-ms > $svr-sts<weighted-mean-rtt-ms>;
}
# select those servers falling in the window defined by the
# minimum round trip time and minimum rtt plus a treshold
for @selected-servers -> $svr {
my Hash $svr-sts = $svr.get-status;
$slctd-svrs.push: $svr
if $svr-sts<weighted-mean-rtt-ms> <= (
$min-rtt-ms + $!uri-obj.options<localThresholdMS>
);
}
$selected-server = $slctd-svrs.pick;
}
}
# done when a suitable server is found
last if $selected-server.defined;
# else wait for status and topology updates
#TODO synchronize with monitor times
sleep $!uri-obj.options<heartbeatFrequencyMS> / 1000.0;
} while ((now - $t0) * 1000) < $!uri-obj.options<serverSelectionTimeoutMS>;
debug-message("searched for {((now - $t0) * 1000).fmt('%.3f')} ms");
if ?$selected-server {
debug-message("server '$selected-server.name()' selected");
}
else {
warn-message("no suitable server selected");
}
$selected-server;
}
#-----------------------------------------------------------------------------
# Add server to todo list.
method add-servers ( Array $hostspecs ) {
trace-message("push $hostspecs[*] on todo list");
$!rw-sem.writer( 'todo', { $!todo-servers.append: |$hostspecs; });
}
#-----------------------------------------------------------------------------
# Check if background process is still running
method !check-discovery-process ( ) {
state $check-count = 0;
if $!background-discovery.status ~~ any(Broken|Kept) {
# set if loop crashed
$!repeat-discovery-loop = False;
info-message(
'server discovery stopped: ' ~ (
$!background-discovery.status ~~ Broken
?? $!background-discovery.cause
!! $!background-discovery.result
)
);
# check every now and then for new servers after discovery-thread has
# finished
unless $!repeat-discovery-loop or $check-count++ % 5 {
self!discover-servers;
}
}
}
#-----------------------------------------------------------------------------
method !discover-servers ( --> Bool ) {
my Bool $found-new-server = False;
# always assume that there are changes
$!rw-sem.writer( 'topology', { $!topology-set = False; } );
# When the server discovery thread is still running $!repeat-discovery-loop
# is still True. In this case we must get the data using semaphores.
# Repeat when a server was found, there might be another one on the stack
my Str $server-name;
repeat {
# Start processing when something is found in todo hash
if $!repeat-discovery-loop {
$server-name = $!rw-sem.writer(
'todo', {
($!todo-servers.shift if $!todo-servers.elems) // Str;
}
);
}
else {
$server-name = ($!todo-servers.shift if $!todo-servers.elems) // Str;
}
# check if a server name is popped from the todo stack
if $server-name.defined {
trace-message("processing server $server-name");
# check if from discovery-loop. if so do the safe access
my Bool $server-processed;
if $!repeat-discovery-loop {
$server-processed = $!rw-sem.reader(
'servers',
{ $!servers{$server-name}:exists; }
);
}
else {
$server-processed = $!servers{$server-name}:exists;
}
# Check if server was managed before
if $server-processed {
trace-message("server $server-name already managed");
}
# new server
else {
# new server, re-examin the topology outcome, so block select-server
# until after topology is calculated.
$found-new-server = True;
# create Server object
my MongoDB::Server $server .= new( :client(self), :$server-name);
# and start server monitoring
$server.server-init;
if $!repeat-discovery-loop {
$!rw-sem.writer( 'servers', {$!servers{$server-name} = $server;});
}
else {
$!servers{$server-name} = $server;
}
} # else
} # if
} while $server-name.defined; # repeat
self.process-topology;
$found-new-server;
}
#-----------------------------------------------------------------------------
method database ( Str:D $name --> MongoDB::Database ) {
MongoDB::Database.new( :client(self), :name($name));
}
#-----------------------------------------------------------------------------
method collection ( Str:D $full-collection-name --> MongoDB::Collection ) {
#TODO check for dot in the name
( my $db-name, my $cll-name) = $full-collection-name.split( '.', 2);
my MongoDB::Database $db .= new( :client(self), :name($db-name));
return $db.collection($cll-name);
}
#-----------------------------------------------------------------------------
# Forced cleanup
#
# cleanup cannot be done in separate thread because everything must be cleaned
# up before other tasks are performed. the client inserts new data while
# removing them here. the last subtest of 110-client failed because of this.
method cleanup ( ) {
$!cleanup-started = True;
# some timing to see if this cleanup can be improved
my Instant $t0 = now;
# stop loop and wait for exit
if $!repeat-discovery-loop {
$!repeat-discovery-loop = False;
$!background-discovery.result;
}
# Remove all servers concurrently. Shouldn't be many per client.
$!rw-sem.writer(
'servers', {
for $!servers.values -> MongoDB::Server $server {
if $server.defined {
# Stop monitoring on server
$server.cleanup;
debug-message(
"server '$server.name()' destroyed after {(now - $t0)} sec"
);
}
}
}
);
$!servers = Nil;
$!todo-servers = Nil;
$!rw-sem.rm-mutex-names(<servers todo topology>);
debug-message("client destroyed after {(now - $t0)} sec");
}
}