Commit | Line | Data |
2156bbdd |
1 | package DBIx::Class::Storage::DBI::Replicated; |
f5d3a5de |
2 | |
ecb65397 |
3 | BEGIN { |
4 | use Carp::Clan qw/^DBIx::Class/; |
d4daee7b |
5 | |
ecb65397 |
6 | ## Modules required for Replication support not required for general DBIC |
7 | ## use, so we explicitly test for these. |
d4daee7b |
8 | |
ecb65397 |
9 | my %replication_required = ( |
62eabf11 |
10 | 'Moose' => '0.87', |
450a317d |
11 | 'MooseX::AttributeHelpers' => '0.21', |
62eabf11 |
12 | 'MooseX::Types' => '0.16', |
bd5da369 |
13 | 'namespace::clean' => '0.11', |
14 | 'Hash::Merge' => '0.11' |
ecb65397 |
15 | ); |
d4daee7b |
16 | |
ecb65397 |
17 | my @didnt_load; |
d4daee7b |
18 | |
ecb65397 |
19 | for my $module (keys %replication_required) { |
20 | eval "use $module $replication_required{$module}"; |
21 | push @didnt_load, "$module $replication_required{$module}" |
22 | if $@; |
23 | } |
d4daee7b |
24 | |
ecb65397 |
25 | croak("@{[ join ', ', @didnt_load ]} are missing and are required for Replication") |
d4daee7b |
26 | if @didnt_load; |
ecb65397 |
27 | } |
28 | |
b2e4d522 |
29 | use Moose; |
26ab719a |
30 | use DBIx::Class::Storage::DBI; |
2bf79155 |
31 | use DBIx::Class::Storage::DBI::Replicated::Pool; |
26ab719a |
32 | use DBIx::Class::Storage::DBI::Replicated::Balancer; |
6a151f58 |
33 | use DBIx::Class::Storage::DBI::Replicated::Types qw/BalancerClassNamePart DBICSchema DBICStorageDBI/; |
41916570 |
34 | use MooseX::Types::Moose qw/ClassName HashRef Object/; |
b2e4d522 |
35 | use Scalar::Util 'reftype'; |
36 | use Carp::Clan qw/^DBIx::Class/; |
b88b85e7 |
37 | use Hash::Merge 'merge'; |
9901aad7 |
38 | |
39 | use namespace::clean -except => 'meta'; |
2bf79155 |
40 | |
41 | =head1 NAME |
42 | |
ecb65397 |
43 | DBIx::Class::Storage::DBI::Replicated - BETA Replicated database support |
2bf79155 |
44 | |
45 | =head1 SYNOPSIS |
46 | |
47 | The Following example shows how to change an existing $schema to a replicated |
48 | storage type, add some replicated (readonly) databases, and perform reporting |
955a6df6 |
49 | tasks. |
2bf79155 |
50 | |
3da4f736 |
51 | You should set the 'storage_type attribute to a replicated type. You should |
d4daee7b |
52 | also define your arguments, such as which balancer you want and any arguments |
3da4f736 |
53 | that the Pool object should get. |
54 | |
64cdad22 |
55 | $schema->storage_type( ['::DBI::Replicated', {balancer=>'::Random'}] ); |
d4daee7b |
56 | |
3da4f736 |
57 | Next, you need to add in the Replicants. Basically this is an array of |
58 | arrayrefs, where each arrayref is database connect information. Think of these |
59 | arguments as what you'd pass to the 'normal' $schema->connect method. |
d4daee7b |
60 | |
64cdad22 |
61 | $schema->storage->connect_replicants( |
62 | [$dsn1, $user, $pass, \%opts], |
63 | [$dsn2, $user, $pass, \%opts], |
64 | [$dsn3, $user, $pass, \%opts], |
65 | ); |
d4daee7b |
66 | |
3da4f736 |
67 | Now, just use the $schema as you normally would. Automatically all reads will |
68 | be delegated to the replicants, while writes to the master. |
69 | |
7e38d850 |
70 | $schema->resultset('Source')->search({name=>'etc'}); |
d4daee7b |
71 | |
3da4f736 |
72 | You can force a given query to use a particular storage using the search |
73 | attribute 'force_pool'. For example: |
d4daee7b |
74 | |
7e38d850 |
75 | my $RS = $schema->resultset('Source')->search(undef, {force_pool=>'master'}); |
3da4f736 |
76 | |
77 | Now $RS will force everything (both reads and writes) to use whatever was setup |
78 | as the master storage. 'master' is hardcoded to always point to the Master, |
79 | but you can also use any Replicant name. Please see: |
212cc5c2 |
80 | L<DBIx::Class::Storage::DBI::Replicated::Pool> and the replicants attribute for more. |
3da4f736 |
81 | |
82 | Also see transactions and L</execute_reliably> for alternative ways to |
83 | force read traffic to the master. In general, you should wrap your statements |
84 | in a transaction when you are reading and writing to the same tables at the |
85 | same time, since your replicants will often lag a bit behind the master. |
212cc5c2 |
86 | |
87 | See L<DBIx::Class::Storage::DBI::Replicated::Instructions> for more help and |
88 | walkthroughs. |
d4daee7b |
89 | |
2bf79155 |
90 | =head1 DESCRIPTION |
91 | |
7e38d850 |
92 | Warning: This class is marked BETA. This has been running a production |
ccb3b897 |
93 | website using MySQL native replication as its backend and we have some decent |
7e38d850 |
94 | test coverage but the code hasn't yet been stressed by a variety of databases. |
95 | Individual DB's may have quirks we are not aware of. Please use this in first |
96 | development and pass along your experiences/bug fixes. |
2bf79155 |
97 | |
98 | This class implements replicated data store for DBI. Currently you can define |
99 | one master and numerous slave database connections. All write-type queries |
100 | (INSERT, UPDATE, DELETE and even LAST_INSERT_ID) are routed to master |
101 | database, all read-type queries (SELECTs) go to the slave database. |
102 | |
103 | Basically, any method request that L<DBIx::Class::Storage::DBI> would normally |
bca099a3 |
104 | handle gets delegated to one of the two attributes: L</read_handler> or to |
105 | L</write_handler>. Additionally, some methods need to be distributed |
2bf79155 |
106 | to all existing storages. This way our storage class is a drop in replacement |
107 | for L<DBIx::Class::Storage::DBI>. |
108 | |
109 | Read traffic is spread across the replicants (slaves) occuring to a user |
110 | selected algorithm. The default algorithm is random weighted. |
111 | |
bca099a3 |
112 | =head1 NOTES |
113 | |
114 | The consistancy betweeen master and replicants is database specific. The Pool |
faaba25f |
115 | gives you a method to validate its replicants, removing and replacing them |
7e38d850 |
116 | when they fail/pass predefined criteria. Please make careful use of the ways |
ecb65397 |
117 | to force a query to run against Master when needed. |
118 | |
119 | =head1 REQUIREMENTS |
120 | |
121 | Replicated Storage has additional requirements not currently part of L<DBIx::Class> |
122 | |
62eabf11 |
123 | Moose => '0.87', |
124 | MooseX::AttributeHelpers => '0.20', |
125 | MooseX::Types => '0.16', |
126 | namespace::clean => '0.11', |
127 | Hash::Merge => '0.11' |
d4daee7b |
128 | |
ecb65397 |
129 | You will need to install these modules manually via CPAN or make them part of the |
130 | Makefile for your distribution. |
2bf79155 |
131 | |
132 | =head1 ATTRIBUTES |
133 | |
134 | This class defines the following attributes. |
135 | |
2ce6e9a6 |
136 | =head2 schema |
137 | |
138 | The underlying L<DBIx::Class::Schema> object this storage is attaching |
139 | |
140 | =cut |
141 | |
142 | has 'schema' => ( |
143 | is=>'rw', |
6a151f58 |
144 | isa=>DBICSchema, |
2ce6e9a6 |
145 | weak_ref=>1, |
146 | required=>1, |
147 | ); |
148 | |
26ab719a |
149 | =head2 pool_type |
2bf79155 |
150 | |
26ab719a |
151 | Contains the classname which will instantiate the L</pool> object. Defaults |
152 | to: L<DBIx::Class::Storage::DBI::Replicated::Pool>. |
2bf79155 |
153 | |
154 | =cut |
155 | |
26ab719a |
156 | has 'pool_type' => ( |
dcdf7b2c |
157 | is=>'rw', |
41916570 |
158 | isa=>ClassName, |
2ce6e9a6 |
159 | default=>'DBIx::Class::Storage::DBI::Replicated::Pool', |
64cdad22 |
160 | handles=>{ |
161 | 'create_pool' => 'new', |
162 | }, |
2bf79155 |
163 | ); |
164 | |
f068a139 |
165 | =head2 pool_args |
166 | |
167 | Contains a hashref of initialized information to pass to the Balancer object. |
212cc5c2 |
168 | See L<DBIx::Class::Storage::DBI::Replicated::Pool> for available arguments. |
f068a139 |
169 | |
170 | =cut |
171 | |
172 | has 'pool_args' => ( |
dcdf7b2c |
173 | is=>'rw', |
41916570 |
174 | isa=>HashRef, |
64cdad22 |
175 | lazy=>1, |
64cdad22 |
176 | default=>sub { {} }, |
f068a139 |
177 | ); |
178 | |
179 | |
26ab719a |
180 | =head2 balancer_type |
2bf79155 |
181 | |
182 | The replication pool requires a balance class to provider the methods for |
183 | choose how to spread the query load across each replicant in the pool. |
184 | |
185 | =cut |
186 | |
26ab719a |
187 | has 'balancer_type' => ( |
dcdf7b2c |
188 | is=>'rw', |
9901aad7 |
189 | isa=>BalancerClassNamePart, |
2ce6e9a6 |
190 | coerce=>1, |
191 | required=>1, |
192 | default=> 'DBIx::Class::Storage::DBI::Replicated::Balancer::First', |
64cdad22 |
193 | handles=>{ |
194 | 'create_balancer' => 'new', |
195 | }, |
2bf79155 |
196 | ); |
197 | |
17b05c13 |
198 | =head2 balancer_args |
199 | |
200 | Contains a hashref of initialized information to pass to the Balancer object. |
212cc5c2 |
201 | See L<DBIx::Class::Storage::DBI::Replicated::Balancer> for available arguments. |
17b05c13 |
202 | |
203 | =cut |
204 | |
205 | has 'balancer_args' => ( |
dcdf7b2c |
206 | is=>'rw', |
41916570 |
207 | isa=>HashRef, |
64cdad22 |
208 | lazy=>1, |
209 | required=>1, |
210 | default=>sub { {} }, |
17b05c13 |
211 | ); |
212 | |
26ab719a |
213 | =head2 pool |
2bf79155 |
214 | |
26ab719a |
215 | Is a <DBIx::Class::Storage::DBI::Replicated::Pool> or derived class. This is a |
216 | container class for one or more replicated databases. |
2bf79155 |
217 | |
218 | =cut |
219 | |
26ab719a |
220 | has 'pool' => ( |
64cdad22 |
221 | is=>'ro', |
222 | isa=>'DBIx::Class::Storage::DBI::Replicated::Pool', |
223 | lazy_build=>1, |
224 | handles=>[qw/ |
6f7344b8 |
225 | connect_replicants |
64cdad22 |
226 | replicants |
227 | has_replicants |
228 | /], |
2bf79155 |
229 | ); |
230 | |
26ab719a |
231 | =head2 balancer |
2bf79155 |
232 | |
26ab719a |
233 | Is a <DBIx::Class::Storage::DBI::Replicated::Balancer> or derived class. This |
234 | is a class that takes a pool (<DBIx::Class::Storage::DBI::Replicated::Pool>) |
2bf79155 |
235 | |
26ab719a |
236 | =cut |
2bf79155 |
237 | |
26ab719a |
238 | has 'balancer' => ( |
dcdf7b2c |
239 | is=>'rw', |
64cdad22 |
240 | isa=>'DBIx::Class::Storage::DBI::Replicated::Balancer', |
241 | lazy_build=>1, |
242 | handles=>[qw/auto_validate_every/], |
26ab719a |
243 | ); |
2bf79155 |
244 | |
cb6ec758 |
245 | =head2 master |
246 | |
247 | The master defines the canonical state for a pool of connected databases. All |
248 | the replicants are expected to match this databases state. Thus, in a classic |
249 | Master / Slaves distributed system, all the slaves are expected to replicate |
250 | the Master's state as quick as possible. This is the only database in the |
251 | pool of databases that is allowed to handle write traffic. |
252 | |
253 | =cut |
254 | |
255 | has 'master' => ( |
64cdad22 |
256 | is=> 'ro', |
6a151f58 |
257 | isa=>DBICStorageDBI, |
64cdad22 |
258 | lazy_build=>1, |
cb6ec758 |
259 | ); |
260 | |
cb6ec758 |
261 | =head1 ATTRIBUTES IMPLEMENTING THE DBIx::Storage::DBI INTERFACE |
262 | |
263 | The following methods are delegated all the methods required for the |
264 | L<DBIx::Class::Storage::DBI> interface. |
265 | |
266 | =head2 read_handler |
267 | |
268 | Defines an object that implements the read side of L<BIx::Class::Storage::DBI>. |
269 | |
270 | =cut |
271 | |
272 | has 'read_handler' => ( |
64cdad22 |
273 | is=>'rw', |
41916570 |
274 | isa=>Object, |
64cdad22 |
275 | lazy_build=>1, |
276 | handles=>[qw/ |
277 | select |
278 | select_single |
279 | columns_info_for |
6f7344b8 |
280 | /], |
cb6ec758 |
281 | ); |
282 | |
cb6ec758 |
283 | =head2 write_handler |
284 | |
285 | Defines an object that implements the write side of L<BIx::Class::Storage::DBI>. |
286 | |
287 | =cut |
288 | |
289 | has 'write_handler' => ( |
64cdad22 |
290 | is=>'ro', |
41916570 |
291 | isa=>Object, |
64cdad22 |
292 | lazy_build=>1, |
6f7344b8 |
293 | handles=>[qw/ |
64cdad22 |
294 | on_connect_do |
6f7344b8 |
295 | on_disconnect_do |
64cdad22 |
296 | connect_info |
297 | throw_exception |
298 | sql_maker |
299 | sqlt_type |
300 | create_ddl_dir |
301 | deployment_statements |
302 | datetime_parser |
6f7344b8 |
303 | datetime_parser_type |
304 | build_datetime_parser |
64cdad22 |
305 | last_insert_id |
306 | insert |
307 | insert_bulk |
308 | update |
309 | delete |
310 | dbh |
2ce6e9a6 |
311 | txn_begin |
64cdad22 |
312 | txn_do |
313 | txn_commit |
314 | txn_rollback |
2ce6e9a6 |
315 | txn_scope_guard |
64cdad22 |
316 | sth |
317 | deploy |
0180bef9 |
318 | with_deferred_fk_checks |
6f7344b8 |
319 | dbh_do |
64cdad22 |
320 | reload_row |
6f7344b8 |
321 | with_deferred_fk_checks |
2ce6e9a6 |
322 | _prep_for_execute |
7fb60fb1 |
323 | |
6f7344b8 |
324 | backup |
325 | is_datatype_numeric |
326 | _count_select |
327 | _subq_count_select |
328 | _subq_update_delete |
90a63099 |
329 | _order_select_columns |
6f7344b8 |
330 | svp_rollback |
331 | svp_begin |
332 | svp_release |
64cdad22 |
333 | /], |
cb6ec758 |
334 | ); |
335 | |
b2e4d522 |
336 | has _master_connect_info_opts => |
337 | (is => 'rw', isa => HashRef, default => sub { {} }); |
338 | |
339 | =head2 around: connect_info |
340 | |
341 | Preserve master's C<connect_info> options (for merging with replicants.) |
dcdf7b2c |
342 | Also set any Replicated related options from connect_info, such as |
343 | C<pool_type>, C<pool_args>, C<balancer_type> and C<balancer_args>. |
b2e4d522 |
344 | |
345 | =cut |
346 | |
347 | around connect_info => sub { |
348 | my ($next, $self, $info, @extra) = @_; |
349 | |
0ce2d0d5 |
350 | my $wantarray = wantarray; |
351 | |
b2e4d522 |
352 | my %opts; |
353 | for my $arg (@$info) { |
354 | next unless (reftype($arg)||'') eq 'HASH'; |
b88b85e7 |
355 | %opts = %{ merge($arg, \%opts) }; |
b2e4d522 |
356 | } |
b2e4d522 |
357 | delete $opts{dsn}; |
358 | |
dcdf7b2c |
359 | if (@opts{qw/pool_type pool_args/}) { |
360 | $self->pool_type(delete $opts{pool_type}) |
361 | if $opts{pool_type}; |
362 | |
b88b85e7 |
363 | $self->pool_args( |
364 | merge((delete $opts{pool_args} || {}), $self->pool_args) |
365 | ); |
dcdf7b2c |
366 | |
67c43863 |
367 | $self->pool($self->_build_pool) |
6f7344b8 |
368 | if $self->pool; |
dcdf7b2c |
369 | } |
370 | |
371 | if (@opts{qw/balancer_type balancer_args/}) { |
372 | $self->balancer_type(delete $opts{balancer_type}) |
373 | if $opts{balancer_type}; |
374 | |
b88b85e7 |
375 | $self->balancer_args( |
376 | merge((delete $opts{balancer_args} || {}), $self->balancer_args) |
377 | ); |
dcdf7b2c |
378 | |
67c43863 |
379 | $self->balancer($self->_build_balancer) |
6f7344b8 |
380 | if $self->balancer; |
dcdf7b2c |
381 | } |
382 | |
b2e4d522 |
383 | $self->_master_connect_info_opts(\%opts); |
384 | |
0ce2d0d5 |
385 | my (@res, $res); |
386 | if ($wantarray) { |
387 | @res = $self->$next($info, @extra); |
388 | } else { |
389 | $res = $self->$next($info, @extra); |
390 | } |
391 | |
fd4eb9c2 |
392 | # Make sure master is blessed into the correct class and apply role to it. |
393 | my $master = $self->master; |
394 | $master->_determine_driver; |
395 | Moose::Meta::Class->initialize(ref $master); |
396 | DBIx::Class::Storage::DBI::Replicated::WithDSN->meta->apply($master); |
0ce2d0d5 |
397 | |
398 | $wantarray ? @res : $res; |
b2e4d522 |
399 | }; |
400 | |
26ab719a |
401 | =head1 METHODS |
2bf79155 |
402 | |
26ab719a |
403 | This class defines the following methods. |
2bf79155 |
404 | |
c354902c |
405 | =head2 BUILDARGS |
2bf79155 |
406 | |
faaba25f |
407 | L<DBIx::Class::Schema> when instantiating its storage passed itself as the |
2ce6e9a6 |
408 | first argument. So we need to massage the arguments a bit so that all the |
409 | bits get put into the correct places. |
2bf79155 |
410 | |
411 | =cut |
412 | |
c354902c |
413 | sub BUILDARGS { |
414 | my ($class, $schema, $storage_type_args, @args) = @_; |
d4daee7b |
415 | |
c354902c |
416 | return { |
6f7344b8 |
417 | schema=>$schema, |
418 | %$storage_type_args, |
419 | @args |
c354902c |
420 | } |
421 | } |
2bf79155 |
422 | |
cb6ec758 |
423 | =head2 _build_master |
2bf79155 |
424 | |
cb6ec758 |
425 | Lazy builder for the L</master> attribute. |
2bf79155 |
426 | |
427 | =cut |
428 | |
cb6ec758 |
429 | sub _build_master { |
2ce6e9a6 |
430 | my $self = shift @_; |
ee356d00 |
431 | my $master = DBIx::Class::Storage::DBI->new($self->schema); |
ee356d00 |
432 | $master |
106d5f3b |
433 | } |
434 | |
26ab719a |
435 | =head2 _build_pool |
2bf79155 |
436 | |
26ab719a |
437 | Lazy builder for the L</pool> attribute. |
2bf79155 |
438 | |
439 | =cut |
440 | |
26ab719a |
441 | sub _build_pool { |
64cdad22 |
442 | my $self = shift @_; |
443 | $self->create_pool(%{$self->pool_args}); |
2bf79155 |
444 | } |
445 | |
26ab719a |
446 | =head2 _build_balancer |
2bf79155 |
447 | |
cb6ec758 |
448 | Lazy builder for the L</balancer> attribute. This takes a Pool object so that |
449 | the balancer knows which pool it's balancing. |
2bf79155 |
450 | |
451 | =cut |
452 | |
26ab719a |
453 | sub _build_balancer { |
64cdad22 |
454 | my $self = shift @_; |
455 | $self->create_balancer( |
6f7344b8 |
456 | pool=>$self->pool, |
64cdad22 |
457 | master=>$self->master, |
458 | %{$self->balancer_args}, |
459 | ); |
2bf79155 |
460 | } |
461 | |
cb6ec758 |
462 | =head2 _build_write_handler |
2bf79155 |
463 | |
cb6ec758 |
464 | Lazy builder for the L</write_handler> attribute. The default is to set this to |
465 | the L</master>. |
50336325 |
466 | |
467 | =cut |
468 | |
cb6ec758 |
469 | sub _build_write_handler { |
64cdad22 |
470 | return shift->master; |
cb6ec758 |
471 | } |
50336325 |
472 | |
cb6ec758 |
473 | =head2 _build_read_handler |
2bf79155 |
474 | |
cb6ec758 |
475 | Lazy builder for the L</read_handler> attribute. The default is to set this to |
476 | the L</balancer>. |
2bf79155 |
477 | |
478 | =cut |
479 | |
cb6ec758 |
480 | sub _build_read_handler { |
64cdad22 |
481 | return shift->balancer; |
cb6ec758 |
482 | } |
50336325 |
483 | |
cb6ec758 |
484 | =head2 around: connect_replicants |
2bf79155 |
485 | |
cb6ec758 |
486 | All calls to connect_replicants needs to have an existing $schema tacked onto |
b2e4d522 |
487 | top of the args, since L<DBIx::Storage::DBI> needs it, and any C<connect_info> |
488 | options merged with the master, with replicant opts having higher priority. |
955a6df6 |
489 | |
cb6ec758 |
490 | =cut |
955a6df6 |
491 | |
b2e4d522 |
492 | around connect_replicants => sub { |
493 | my ($next, $self, @args) = @_; |
494 | |
495 | for my $r (@args) { |
496 | $r = [ $r ] unless reftype $r eq 'ARRAY'; |
497 | |
498 | croak "coderef replicant connect_info not supported" |
499 | if ref $r->[0] && reftype $r->[0] eq 'CODE'; |
500 | |
501 | # any connect_info options? |
502 | my $i = 0; |
503 | $i++ while $i < @$r && (reftype($r->[$i])||'') ne 'HASH'; |
504 | |
6f7344b8 |
505 | # make one if none |
b2e4d522 |
506 | $r->[$i] = {} unless $r->[$i]; |
507 | |
508 | # merge if two hashes |
b88b85e7 |
509 | my @hashes = @$r[$i .. $#{$r}]; |
510 | |
511 | croak "invalid connect_info options" |
512 | if (grep { reftype($_) eq 'HASH' } @hashes) != @hashes; |
513 | |
514 | croak "too many hashrefs in connect_info" |
515 | if @hashes > 2; |
516 | |
517 | my %opts = %{ merge(reverse @hashes) }; |
518 | |
519 | # delete them |
b2e4d522 |
520 | splice @$r, $i+1, ($#{$r} - $i), (); |
521 | |
522 | # merge with master |
b88b85e7 |
523 | %opts = %{ merge(\%opts, $self->_master_connect_info_opts) }; |
b2e4d522 |
524 | |
525 | # update |
526 | $r->[$i] = \%opts; |
527 | } |
528 | |
529 | $self->$next($self->schema, @args); |
955a6df6 |
530 | }; |
2bf79155 |
531 | |
2bf79155 |
532 | =head2 all_storages |
533 | |
534 | Returns an array of of all the connected storage backends. The first element |
535 | in the returned array is the master, and the remainings are each of the |
536 | replicants. |
537 | |
538 | =cut |
539 | |
540 | sub all_storages { |
64cdad22 |
541 | my $self = shift @_; |
542 | return grep {defined $_ && blessed $_} ( |
543 | $self->master, |
6412a592 |
544 | values %{ $self->replicants }, |
64cdad22 |
545 | ); |
2bf79155 |
546 | } |
547 | |
c4d3fae2 |
548 | =head2 execute_reliably ($coderef, ?@args) |
549 | |
550 | Given a coderef, saves the current state of the L</read_handler>, forces it to |
551 | use reliable storage (ie sets it to the master), executes a coderef and then |
552 | restores the original state. |
553 | |
554 | Example: |
555 | |
64cdad22 |
556 | my $reliably = sub { |
557 | my $name = shift @_; |
558 | $schema->resultset('User')->create({name=>$name}); |
559 | my $user_rs = $schema->resultset('User')->find({name=>$name}); |
560 | return $user_rs; |
561 | }; |
c4d3fae2 |
562 | |
64cdad22 |
563 | my $user_rs = $schema->storage->execute_reliably($reliably, 'John'); |
c4d3fae2 |
564 | |
565 | Use this when you must be certain of your database state, such as when you just |
566 | inserted something and need to get a resultset including it, etc. |
567 | |
568 | =cut |
569 | |
570 | sub execute_reliably { |
64cdad22 |
571 | my ($self, $coderef, @args) = @_; |
d4daee7b |
572 | |
64cdad22 |
573 | unless( ref $coderef eq 'CODE') { |
574 | $self->throw_exception('Second argument must be a coderef'); |
575 | } |
d4daee7b |
576 | |
64cdad22 |
577 | ##Get copy of master storage |
578 | my $master = $self->master; |
d4daee7b |
579 | |
64cdad22 |
580 | ##Get whatever the current read hander is |
581 | my $current = $self->read_handler; |
d4daee7b |
582 | |
64cdad22 |
583 | ##Set the read handler to master |
584 | $self->read_handler($master); |
d4daee7b |
585 | |
64cdad22 |
586 | ## do whatever the caller needs |
587 | my @result; |
588 | my $want_array = wantarray; |
d4daee7b |
589 | |
64cdad22 |
590 | eval { |
591 | if($want_array) { |
592 | @result = $coderef->(@args); |
593 | } elsif(defined $want_array) { |
594 | ($result[0]) = ($coderef->(@args)); |
ed213e85 |
595 | } else { |
64cdad22 |
596 | $coderef->(@args); |
6f7344b8 |
597 | } |
64cdad22 |
598 | }; |
d4daee7b |
599 | |
64cdad22 |
600 | ##Reset to the original state |
6f7344b8 |
601 | $self->read_handler($current); |
d4daee7b |
602 | |
64cdad22 |
603 | ##Exception testing has to come last, otherwise you might leave the |
604 | ##read_handler set to master. |
d4daee7b |
605 | |
64cdad22 |
606 | if($@) { |
607 | $self->throw_exception("coderef returned an error: $@"); |
608 | } else { |
609 | return $want_array ? @result : $result[0]; |
610 | } |
c4d3fae2 |
611 | } |
612 | |
cb6ec758 |
613 | =head2 set_reliable_storage |
614 | |
615 | Sets the current $schema to be 'reliable', that is all queries, both read and |
616 | write are sent to the master |
d4daee7b |
617 | |
cb6ec758 |
618 | =cut |
619 | |
620 | sub set_reliable_storage { |
64cdad22 |
621 | my $self = shift @_; |
622 | my $schema = $self->schema; |
623 | my $write_handler = $self->schema->storage->write_handler; |
d4daee7b |
624 | |
64cdad22 |
625 | $schema->storage->read_handler($write_handler); |
cb6ec758 |
626 | } |
627 | |
628 | =head2 set_balanced_storage |
629 | |
630 | Sets the current $schema to be use the </balancer> for all reads, while all |
631 | writea are sent to the master only |
d4daee7b |
632 | |
cb6ec758 |
633 | =cut |
634 | |
635 | sub set_balanced_storage { |
64cdad22 |
636 | my $self = shift @_; |
637 | my $schema = $self->schema; |
bd5da369 |
638 | my $balanced_handler = $self->schema->storage->balancer; |
d4daee7b |
639 | |
bd5da369 |
640 | $schema->storage->read_handler($balanced_handler); |
cb6ec758 |
641 | } |
2bf79155 |
642 | |
643 | =head2 connected |
644 | |
645 | Check that the master and at least one of the replicants is connected. |
646 | |
647 | =cut |
648 | |
649 | sub connected { |
64cdad22 |
650 | my $self = shift @_; |
651 | return |
652 | $self->master->connected && |
653 | $self->pool->connected_replicants; |
2bf79155 |
654 | } |
655 | |
2bf79155 |
656 | =head2 ensure_connected |
657 | |
658 | Make sure all the storages are connected. |
659 | |
660 | =cut |
661 | |
662 | sub ensure_connected { |
64cdad22 |
663 | my $self = shift @_; |
664 | foreach my $source ($self->all_storages) { |
665 | $source->ensure_connected(@_); |
666 | } |
2bf79155 |
667 | } |
668 | |
2bf79155 |
669 | =head2 limit_dialect |
670 | |
671 | Set the limit_dialect for all existing storages |
672 | |
673 | =cut |
674 | |
675 | sub limit_dialect { |
64cdad22 |
676 | my $self = shift @_; |
677 | foreach my $source ($self->all_storages) { |
678 | $source->limit_dialect(@_); |
679 | } |
3fbe08e3 |
680 | return $self->master->quote_char; |
2bf79155 |
681 | } |
682 | |
2bf79155 |
683 | =head2 quote_char |
684 | |
685 | Set the quote_char for all existing storages |
686 | |
687 | =cut |
688 | |
689 | sub quote_char { |
64cdad22 |
690 | my $self = shift @_; |
691 | foreach my $source ($self->all_storages) { |
692 | $source->quote_char(@_); |
693 | } |
3fbe08e3 |
694 | return $self->master->quote_char; |
2bf79155 |
695 | } |
696 | |
2bf79155 |
697 | =head2 name_sep |
698 | |
699 | Set the name_sep for all existing storages |
700 | |
701 | =cut |
702 | |
703 | sub name_sep { |
64cdad22 |
704 | my $self = shift @_; |
705 | foreach my $source ($self->all_storages) { |
706 | $source->name_sep(@_); |
707 | } |
3fbe08e3 |
708 | return $self->master->name_sep; |
2bf79155 |
709 | } |
710 | |
2bf79155 |
711 | =head2 set_schema |
712 | |
713 | Set the schema object for all existing storages |
714 | |
715 | =cut |
716 | |
717 | sub set_schema { |
64cdad22 |
718 | my $self = shift @_; |
719 | foreach my $source ($self->all_storages) { |
720 | $source->set_schema(@_); |
721 | } |
2bf79155 |
722 | } |
723 | |
2bf79155 |
724 | =head2 debug |
725 | |
726 | set a debug flag across all storages |
727 | |
728 | =cut |
729 | |
730 | sub debug { |
64cdad22 |
731 | my $self = shift @_; |
3fbe08e3 |
732 | if(@_) { |
733 | foreach my $source ($self->all_storages) { |
734 | $source->debug(@_); |
6f7344b8 |
735 | } |
64cdad22 |
736 | } |
3fbe08e3 |
737 | return $self->master->debug; |
2bf79155 |
738 | } |
739 | |
2bf79155 |
740 | =head2 debugobj |
741 | |
742 | set a debug object across all storages |
743 | |
744 | =cut |
745 | |
746 | sub debugobj { |
64cdad22 |
747 | my $self = shift @_; |
3fbe08e3 |
748 | if(@_) { |
749 | foreach my $source ($self->all_storages) { |
750 | $source->debugobj(@_); |
6f7344b8 |
751 | } |
64cdad22 |
752 | } |
3fbe08e3 |
753 | return $self->master->debugobj; |
2bf79155 |
754 | } |
755 | |
2bf79155 |
756 | =head2 debugfh |
757 | |
758 | set a debugfh object across all storages |
759 | |
760 | =cut |
761 | |
762 | sub debugfh { |
64cdad22 |
763 | my $self = shift @_; |
3fbe08e3 |
764 | if(@_) { |
765 | foreach my $source ($self->all_storages) { |
766 | $source->debugfh(@_); |
6f7344b8 |
767 | } |
64cdad22 |
768 | } |
3fbe08e3 |
769 | return $self->master->debugfh; |
2bf79155 |
770 | } |
771 | |
2bf79155 |
772 | =head2 debugcb |
773 | |
774 | set a debug callback across all storages |
775 | |
776 | =cut |
777 | |
778 | sub debugcb { |
64cdad22 |
779 | my $self = shift @_; |
3fbe08e3 |
780 | if(@_) { |
781 | foreach my $source ($self->all_storages) { |
782 | $source->debugcb(@_); |
6f7344b8 |
783 | } |
64cdad22 |
784 | } |
3fbe08e3 |
785 | return $self->master->debugcb; |
2bf79155 |
786 | } |
787 | |
2bf79155 |
788 | =head2 disconnect |
789 | |
790 | disconnect everything |
791 | |
792 | =cut |
793 | |
794 | sub disconnect { |
64cdad22 |
795 | my $self = shift @_; |
796 | foreach my $source ($self->all_storages) { |
797 | $source->disconnect(@_); |
798 | } |
2bf79155 |
799 | } |
800 | |
b2e4d522 |
801 | =head2 cursor_class |
802 | |
803 | set cursor class on all storages, or return master's |
804 | |
805 | =cut |
806 | |
807 | sub cursor_class { |
808 | my ($self, $cursor_class) = @_; |
809 | |
810 | if ($cursor_class) { |
811 | $_->cursor_class($cursor_class) for $self->all_storages; |
812 | } |
813 | $self->master->cursor_class; |
814 | } |
d4daee7b |
815 | |
7e38d850 |
816 | =head1 GOTCHAS |
817 | |
818 | Due to the fact that replicants can lag behind a master, you must take care to |
819 | make sure you use one of the methods to force read queries to a master should |
820 | you need realtime data integrity. For example, if you insert a row, and then |
821 | immediately re-read it from the database (say, by doing $row->discard_changes) |
822 | or you insert a row and then immediately build a query that expects that row |
823 | to be an item, you should force the master to handle reads. Otherwise, due to |
824 | the lag, there is no certainty your data will be in the expected state. |
825 | |
826 | For data integrity, all transactions automatically use the master storage for |
827 | all read and write queries. Using a transaction is the preferred and recommended |
828 | method to force the master to handle all read queries. |
829 | |
830 | Otherwise, you can force a single query to use the master with the 'force_pool' |
831 | attribute: |
832 | |
833 | my $row = $resultset->search(undef, {force_pool=>'master'})->find($pk); |
834 | |
835 | This attribute will safely be ignore by non replicated storages, so you can use |
836 | the same code for both types of systems. |
837 | |
838 | Lastly, you can use the L</execute_reliably> method, which works very much like |
839 | a transaction. |
840 | |
841 | For debugging, you can turn replication on/off with the methods L</set_reliable_storage> |
842 | and L</set_balanced_storage>, however this operates at a global level and is not |
843 | suitable if you have a shared Schema object being used by multiple processes, |
844 | such as on a web application server. You can get around this limitation by |
845 | using the Schema clone method. |
846 | |
847 | my $new_schema = $schema->clone; |
848 | $new_schema->set_reliable_storage; |
d4daee7b |
849 | |
7e38d850 |
850 | ## $new_schema will use only the Master storage for all reads/writes while |
851 | ## the $schema object will use replicated storage. |
852 | |
f5d3a5de |
853 | =head1 AUTHOR |
854 | |
64cdad22 |
855 | John Napiorkowski <john.napiorkowski@takkle.com> |
f5d3a5de |
856 | |
c4d3fae2 |
857 | Based on code originated by: |
f5d3a5de |
858 | |
64cdad22 |
859 | Norbert Csongrádi <bert@cpan.org> |
860 | Peter Siklósi <einon@einon.hu> |
2156bbdd |
861 | |
f5d3a5de |
862 | =head1 LICENSE |
863 | |
864 | You may distribute this code under the same terms as Perl itself. |
865 | |
866 | =cut |
867 | |
c354902c |
868 | __PACKAGE__->meta->make_immutable; |
869 | |
f5d3a5de |
870 | 1; |