Commit | Line | Data |
2156bbdd |
1 | package DBIx::Class::Storage::DBI::Replicated; |
f5d3a5de |
2 | |
ecb65397 |
3 | BEGIN { |
a34b0c89 |
4 | use DBIx::Class; |
70c28808 |
5 | die('The following modules are required for Replication ' . DBIx::Class::Optional::Dependencies->req_missing_for ('replicated') . "\n" ) |
a34b0c89 |
6 | unless DBIx::Class::Optional::Dependencies->req_ok_for ('replicated'); |
ecb65397 |
7 | } |
8 | |
b2e4d522 |
9 | use Moose; |
26ab719a |
10 | use DBIx::Class::Storage::DBI; |
2bf79155 |
11 | use DBIx::Class::Storage::DBI::Replicated::Pool; |
26ab719a |
12 | use DBIx::Class::Storage::DBI::Replicated::Balancer; |
6a151f58 |
13 | use DBIx::Class::Storage::DBI::Replicated::Types qw/BalancerClassNamePart DBICSchema DBICStorageDBI/; |
41916570 |
14 | use MooseX::Types::Moose qw/ClassName HashRef Object/; |
b2e4d522 |
15 | use Scalar::Util 'reftype'; |
e666c5fd |
16 | use Hash::Merge; |
7da56142 |
17 | use List::Util qw/min max reduce/; |
1abccf54 |
18 | use Context::Preserve 'preserve_context'; |
ed7ab0f4 |
19 | use Try::Tiny; |
9901aad7 |
20 | |
21 | use namespace::clean -except => 'meta'; |
2bf79155 |
22 | |
e8c31aec |
23 | =encoding utf8 |
24 | |
2bf79155 |
25 | =head1 NAME |
26 | |
ecb65397 |
27 | DBIx::Class::Storage::DBI::Replicated - BETA Replicated database support |
2bf79155 |
28 | |
29 | =head1 SYNOPSIS |
30 | |
31 | The Following example shows how to change an existing $schema to a replicated |
48580715 |
32 | storage type, add some replicated (read-only) databases, and perform reporting |
955a6df6 |
33 | tasks. |
2bf79155 |
34 | |
3da4f736 |
35 | You should set the 'storage_type attribute to a replicated type. You should |
d4daee7b |
36 | also define your arguments, such as which balancer you want and any arguments |
3da4f736 |
37 | that the Pool object should get. |
38 | |
ce854fd3 |
39 | my $schema = Schema::Class->clone; |
64cdad22 |
40 | $schema->storage_type( ['::DBI::Replicated', {balancer=>'::Random'}] ); |
ce854fd3 |
41 | $schema->connection(...); |
d4daee7b |
42 | |
fd323bf1 |
43 | Next, you need to add in the Replicants. Basically this is an array of |
3da4f736 |
44 | arrayrefs, where each arrayref is database connect information. Think of these |
45 | arguments as what you'd pass to the 'normal' $schema->connect method. |
d4daee7b |
46 | |
64cdad22 |
47 | $schema->storage->connect_replicants( |
48 | [$dsn1, $user, $pass, \%opts], |
49 | [$dsn2, $user, $pass, \%opts], |
50 | [$dsn3, $user, $pass, \%opts], |
51 | ); |
d4daee7b |
52 | |
3da4f736 |
53 | Now, just use the $schema as you normally would. Automatically all reads will |
54 | be delegated to the replicants, while writes to the master. |
55 | |
7e38d850 |
56 | $schema->resultset('Source')->search({name=>'etc'}); |
d4daee7b |
57 | |
3da4f736 |
58 | You can force a given query to use a particular storage using the search |
59 | attribute 'force_pool'. For example: |
d4daee7b |
60 | |
d7c37d66 |
61 | my $rs = $schema->resultset('Source')->search(undef, {force_pool=>'master'}); |
3da4f736 |
62 | |
d7c37d66 |
63 | Now $rs will force everything (both reads and writes) to use whatever was setup |
fd323bf1 |
64 | as the master storage. 'master' is hardcoded to always point to the Master, |
3da4f736 |
65 | but you can also use any Replicant name. Please see: |
212cc5c2 |
66 | L<DBIx::Class::Storage::DBI::Replicated::Pool> and the replicants attribute for more. |
3da4f736 |
67 | |
68 | Also see transactions and L</execute_reliably> for alternative ways to |
69 | force read traffic to the master. In general, you should wrap your statements |
70 | in a transaction when you are reading and writing to the same tables at the |
71 | same time, since your replicants will often lag a bit behind the master. |
212cc5c2 |
72 | |
d7c37d66 |
73 | If you have a multi-statement read only transaction you can force it to select |
74 | a random server in the pool by: |
75 | |
76 | my $rs = $schema->resultset('Source')->search( undef, |
77 | { force_pool => $db->storage->read_handler->next_storage } |
78 | ); |
d4daee7b |
79 | |
2bf79155 |
80 | =head1 DESCRIPTION |
81 | |
7e38d850 |
82 | Warning: This class is marked BETA. This has been running a production |
ccb3b897 |
83 | website using MySQL native replication as its backend and we have some decent |
7e38d850 |
84 | test coverage but the code hasn't yet been stressed by a variety of databases. |
48580715 |
85 | Individual DBs may have quirks we are not aware of. Please use this in first |
7e38d850 |
86 | development and pass along your experiences/bug fixes. |
2bf79155 |
87 | |
88 | This class implements replicated data store for DBI. Currently you can define |
89 | one master and numerous slave database connections. All write-type queries |
90 | (INSERT, UPDATE, DELETE and even LAST_INSERT_ID) are routed to master |
91 | database, all read-type queries (SELECTs) go to the slave database. |
92 | |
93 | Basically, any method request that L<DBIx::Class::Storage::DBI> would normally |
bca099a3 |
94 | handle gets delegated to one of the two attributes: L</read_handler> or to |
95 | L</write_handler>. Additionally, some methods need to be distributed |
2bf79155 |
96 | to all existing storages. This way our storage class is a drop in replacement |
97 | for L<DBIx::Class::Storage::DBI>. |
98 | |
48580715 |
99 | Read traffic is spread across the replicants (slaves) occurring to a user |
2bf79155 |
100 | selected algorithm. The default algorithm is random weighted. |
101 | |
bca099a3 |
102 | =head1 NOTES |
103 | |
48580715 |
104 | The consistency between master and replicants is database specific. The Pool |
faaba25f |
105 | gives you a method to validate its replicants, removing and replacing them |
7e38d850 |
106 | when they fail/pass predefined criteria. Please make careful use of the ways |
ecb65397 |
107 | to force a query to run against Master when needed. |
108 | |
109 | =head1 REQUIREMENTS |
110 | |
a34b0c89 |
111 | Replicated Storage has additional requirements not currently part of |
aa8b2277 |
112 | L<DBIx::Class>. See L<DBIx::Class::Optional::Dependencies> for more details. |
2bf79155 |
113 | |
114 | =head1 ATTRIBUTES |
115 | |
116 | This class defines the following attributes. |
117 | |
2ce6e9a6 |
118 | =head2 schema |
119 | |
120 | The underlying L<DBIx::Class::Schema> object this storage is attaching |
121 | |
122 | =cut |
123 | |
124 | has 'schema' => ( |
125 | is=>'rw', |
6a151f58 |
126 | isa=>DBICSchema, |
2ce6e9a6 |
127 | weak_ref=>1, |
128 | required=>1, |
129 | ); |
130 | |
26ab719a |
131 | =head2 pool_type |
2bf79155 |
132 | |
fd323bf1 |
133 | Contains the classname which will instantiate the L</pool> object. Defaults |
26ab719a |
134 | to: L<DBIx::Class::Storage::DBI::Replicated::Pool>. |
2bf79155 |
135 | |
136 | =cut |
137 | |
26ab719a |
138 | has 'pool_type' => ( |
dcdf7b2c |
139 | is=>'rw', |
41916570 |
140 | isa=>ClassName, |
2ce6e9a6 |
141 | default=>'DBIx::Class::Storage::DBI::Replicated::Pool', |
64cdad22 |
142 | handles=>{ |
143 | 'create_pool' => 'new', |
144 | }, |
2bf79155 |
145 | ); |
146 | |
f068a139 |
147 | =head2 pool_args |
148 | |
149 | Contains a hashref of initialized information to pass to the Balancer object. |
212cc5c2 |
150 | See L<DBIx::Class::Storage::DBI::Replicated::Pool> for available arguments. |
f068a139 |
151 | |
152 | =cut |
153 | |
154 | has 'pool_args' => ( |
dcdf7b2c |
155 | is=>'rw', |
41916570 |
156 | isa=>HashRef, |
64cdad22 |
157 | lazy=>1, |
64cdad22 |
158 | default=>sub { {} }, |
f068a139 |
159 | ); |
160 | |
161 | |
26ab719a |
162 | =head2 balancer_type |
2bf79155 |
163 | |
164 | The replication pool requires a balance class to provider the methods for |
165 | choose how to spread the query load across each replicant in the pool. |
166 | |
167 | =cut |
168 | |
26ab719a |
169 | has 'balancer_type' => ( |
dcdf7b2c |
170 | is=>'rw', |
9901aad7 |
171 | isa=>BalancerClassNamePart, |
2ce6e9a6 |
172 | coerce=>1, |
173 | required=>1, |
174 | default=> 'DBIx::Class::Storage::DBI::Replicated::Balancer::First', |
64cdad22 |
175 | handles=>{ |
176 | 'create_balancer' => 'new', |
177 | }, |
2bf79155 |
178 | ); |
179 | |
17b05c13 |
180 | =head2 balancer_args |
181 | |
182 | Contains a hashref of initialized information to pass to the Balancer object. |
212cc5c2 |
183 | See L<DBIx::Class::Storage::DBI::Replicated::Balancer> for available arguments. |
17b05c13 |
184 | |
185 | =cut |
186 | |
187 | has 'balancer_args' => ( |
dcdf7b2c |
188 | is=>'rw', |
41916570 |
189 | isa=>HashRef, |
64cdad22 |
190 | lazy=>1, |
191 | required=>1, |
192 | default=>sub { {} }, |
17b05c13 |
193 | ); |
194 | |
26ab719a |
195 | =head2 pool |
2bf79155 |
196 | |
370f78d4 |
197 | Is a L<DBIx::Class::Storage::DBI::Replicated::Pool> or derived class. This is a |
26ab719a |
198 | container class for one or more replicated databases. |
2bf79155 |
199 | |
200 | =cut |
201 | |
26ab719a |
202 | has 'pool' => ( |
64cdad22 |
203 | is=>'ro', |
204 | isa=>'DBIx::Class::Storage::DBI::Replicated::Pool', |
205 | lazy_build=>1, |
206 | handles=>[qw/ |
6f7344b8 |
207 | connect_replicants |
64cdad22 |
208 | replicants |
209 | has_replicants |
210 | /], |
2bf79155 |
211 | ); |
212 | |
26ab719a |
213 | =head2 balancer |
2bf79155 |
214 | |
370f78d4 |
215 | Is a L<DBIx::Class::Storage::DBI::Replicated::Balancer> or derived class. This |
216 | is a class that takes a pool (L<DBIx::Class::Storage::DBI::Replicated::Pool>) |
2bf79155 |
217 | |
26ab719a |
218 | =cut |
2bf79155 |
219 | |
26ab719a |
220 | has 'balancer' => ( |
dcdf7b2c |
221 | is=>'rw', |
64cdad22 |
222 | isa=>'DBIx::Class::Storage::DBI::Replicated::Balancer', |
223 | lazy_build=>1, |
224 | handles=>[qw/auto_validate_every/], |
26ab719a |
225 | ); |
2bf79155 |
226 | |
cb6ec758 |
227 | =head2 master |
228 | |
229 | The master defines the canonical state for a pool of connected databases. All |
230 | the replicants are expected to match this databases state. Thus, in a classic |
231 | Master / Slaves distributed system, all the slaves are expected to replicate |
232 | the Master's state as quick as possible. This is the only database in the |
233 | pool of databases that is allowed to handle write traffic. |
234 | |
235 | =cut |
236 | |
237 | has 'master' => ( |
64cdad22 |
238 | is=> 'ro', |
6a151f58 |
239 | isa=>DBICStorageDBI, |
64cdad22 |
240 | lazy_build=>1, |
cb6ec758 |
241 | ); |
242 | |
cb6ec758 |
243 | =head1 ATTRIBUTES IMPLEMENTING THE DBIx::Storage::DBI INTERFACE |
244 | |
fd323bf1 |
245 | The following methods are delegated all the methods required for the |
cb6ec758 |
246 | L<DBIx::Class::Storage::DBI> interface. |
247 | |
cb6ec758 |
248 | =cut |
249 | |
4bea1fe7 |
250 | my $method_dispatch = { |
251 | writer => [qw/ |
64cdad22 |
252 | on_connect_do |
6f7344b8 |
253 | on_disconnect_do |
3244fdcc |
254 | on_connect_call |
255 | on_disconnect_call |
64cdad22 |
256 | connect_info |
3244fdcc |
257 | _connect_info |
64cdad22 |
258 | throw_exception |
259 | sql_maker |
260 | sqlt_type |
261 | create_ddl_dir |
262 | deployment_statements |
263 | datetime_parser |
6f7344b8 |
264 | datetime_parser_type |
265 | build_datetime_parser |
64cdad22 |
266 | last_insert_id |
267 | insert |
268 | insert_bulk |
269 | update |
270 | delete |
271 | dbh |
2ce6e9a6 |
272 | txn_begin |
64cdad22 |
273 | txn_do |
274 | txn_commit |
275 | txn_rollback |
2ce6e9a6 |
276 | txn_scope_guard |
90d7422f |
277 | _exec_txn_rollback |
278 | _exec_txn_begin |
279 | _exec_txn_commit |
64cdad22 |
280 | deploy |
0180bef9 |
281 | with_deferred_fk_checks |
6f7344b8 |
282 | dbh_do |
2ce6e9a6 |
283 | _prep_for_execute |
6f7344b8 |
284 | is_datatype_numeric |
285 | _count_select |
6f7344b8 |
286 | svp_rollback |
287 | svp_begin |
288 | svp_release |
e398f77e |
289 | relname_to_table_alias |
3244fdcc |
290 | _dbh_last_insert_id |
3244fdcc |
291 | _default_dbi_connect_attributes |
292 | _dbi_connect_info |
b9ca4ff1 |
293 | _dbic_connect_attributes |
3244fdcc |
294 | auto_savepoint |
0e773352 |
295 | _query_start |
3244fdcc |
296 | _query_end |
0e773352 |
297 | _format_for_trace |
298 | _dbi_attrs_for_bind |
3244fdcc |
299 | bind_attribute_by_data_type |
300 | transaction_depth |
301 | _dbh |
302 | _select_args |
52cef7e3 |
303 | _dbh_execute_for_fetch |
3244fdcc |
304 | _sql_maker |
3244fdcc |
305 | _dbh_execute_inserts_with_no_binds |
306 | _select_args_to_query |
5e782048 |
307 | _gen_sql_bind |
3244fdcc |
308 | _svp_generate_name |
3244fdcc |
309 | _normalize_connect_info |
310 | _parse_connect_do |
3244fdcc |
311 | savepoints |
3244fdcc |
312 | _sql_maker_opts |
313 | _conn_pid |
3244fdcc |
314 | _dbh_autocommit |
315 | _native_data_type |
316 | _get_dbh |
317 | sql_maker_class |
3244fdcc |
318 | _execute |
319 | _do_query |
3244fdcc |
320 | _dbh_execute |
5b4f3fd0 |
321 | /, Class::MOP::Class->initialize('DBIx::Class::Storage::DBIHacks')->get_method_list ], |
4bea1fe7 |
322 | reader => [qw/ |
323 | select |
324 | select_single |
325 | columns_info_for |
326 | _dbh_columns_info_for |
327 | _select |
328 | /], |
329 | unimplemented => [qw/ |
330 | _arm_global_destructor |
331 | _verify_pid |
332 | |
333 | get_use_dbms_capability |
334 | set_use_dbms_capability |
335 | get_dbms_capability |
336 | set_dbms_capability |
337 | _dbh_details |
338 | _dbh_get_info |
339 | |
75d3bdb2 |
340 | _determine_connector_driver |
341 | _describe_connection |
342 | _warn_undetermined_driver |
343 | |
4bea1fe7 |
344 | sql_limit_dialect |
345 | sql_quote_char |
346 | sql_name_sep |
347 | |
4bea1fe7 |
348 | _prefetch_autovalues |
fabbd5cc |
349 | _perform_autoinc_retrieval |
350 | _autoinc_supplied_for_op |
4bea1fe7 |
351 | |
eec07bca |
352 | _resolve_bindattrs |
353 | |
4bea1fe7 |
354 | _max_column_bytesize |
355 | _is_lob_type |
356 | _is_binary_lob_type |
5efba7fc |
357 | _is_binary_type |
4bea1fe7 |
358 | _is_text_lob_type |
402ac1c9 |
359 | |
9930caaf |
360 | _prepare_sth |
361 | _bind_sth_params |
4bea1fe7 |
362 | /,( |
363 | # the capability framework |
364 | # not sure if CMOP->initialize does evil things to DBIC::S::DBI, fix if a problem |
365 | grep |
366 | { $_ =~ /^ _ (?: use | supports | determine_supports ) _ /x } |
367 | ( Class::MOP::Class->initialize('DBIx::Class::Storage::DBI')->get_all_method_names ) |
368 | )], |
369 | }; |
370 | |
371 | if (DBIx::Class::_ENV_::DBICTEST) { |
372 | |
373 | my $seen; |
374 | for my $type (keys %$method_dispatch) { |
375 | for (@{$method_dispatch->{$type}}) { |
376 | push @{$seen->{$_}}, $type; |
377 | } |
378 | } |
cb6ec758 |
379 | |
4bea1fe7 |
380 | if (my @dupes = grep { @{$seen->{$_}} > 1 } keys %$seen) { |
381 | die(join "\n", '', |
382 | 'The following methods show up multiple times in ::Storage::DBI::Replicated handlers:', |
383 | (map { "$_: " . (join ', ', @{$seen->{$_}}) } sort @dupes), |
384 | '', |
385 | ); |
386 | } |
bbdda281 |
387 | |
4bea1fe7 |
388 | if (my @cant = grep { ! DBIx::Class::Storage::DBI->can($_) } keys %$seen) { |
389 | die(join "\n", '', |
390 | '::Storage::DBI::Replicated specifies handling of the following *NON EXISTING* ::Storage::DBI methods:', |
391 | @cant, |
392 | '', |
393 | ); |
394 | } |
395 | } |
bbdda281 |
396 | |
4bea1fe7 |
397 | for my $method (@{$method_dispatch->{unimplemented}}) { |
398 | __PACKAGE__->meta->add_method($method, sub { |
70c28808 |
399 | my $self = shift; |
e705f529 |
400 | $self->throw_exception("$method() must not be called on ".(blessed $self).' objects'); |
4bea1fe7 |
401 | }); |
402 | } |
31a8aaaf |
403 | |
4bea1fe7 |
404 | =head2 read_handler |
584ea6e4 |
405 | |
4bea1fe7 |
406 | Defines an object that implements the read side of L<BIx::Class::Storage::DBI>. |
584ea6e4 |
407 | |
4bea1fe7 |
408 | =cut |
409 | |
410 | has 'read_handler' => ( |
411 | is=>'rw', |
412 | isa=>Object, |
413 | lazy_build=>1, |
414 | handles=>$method_dispatch->{reader}, |
e471ab87 |
415 | ); |
416 | |
4bea1fe7 |
417 | =head2 write_handler |
418 | |
419 | Defines an object that implements the write side of L<BIx::Class::Storage::DBI>, |
420 | as well as methods that don't write or read that can be called on only one |
421 | storage, methods that return a C<$dbh>, and any methods that don't make sense to |
422 | run on a replicant. |
423 | |
424 | =cut |
425 | |
426 | has 'write_handler' => ( |
427 | is=>'ro', |
428 | isa=>Object, |
429 | lazy_build=>1, |
430 | handles=>$method_dispatch->{writer}, |
7f4433eb |
431 | ); |
432 | |
4bea1fe7 |
433 | |
6d766626 |
434 | |
b2e4d522 |
435 | has _master_connect_info_opts => |
436 | (is => 'rw', isa => HashRef, default => sub { {} }); |
437 | |
438 | =head2 around: connect_info |
439 | |
48580715 |
440 | Preserves master's C<connect_info> options (for merging with replicants.) |
441 | Also sets any Replicated-related options from connect_info, such as |
dcdf7b2c |
442 | C<pool_type>, C<pool_args>, C<balancer_type> and C<balancer_args>. |
b2e4d522 |
443 | |
444 | =cut |
445 | |
446 | around connect_info => sub { |
447 | my ($next, $self, $info, @extra) = @_; |
448 | |
1fccee7b |
449 | $self->throw_exception( |
450 | 'connect_info can not be retrieved from a replicated storage - ' |
451 | . 'accessor must be called on a specific pool instance' |
452 | ) unless defined $info; |
453 | |
282a9a4f |
454 | my $merge = Hash::Merge->new('LEFT_PRECEDENT'); |
e666c5fd |
455 | |
b2e4d522 |
456 | my %opts; |
457 | for my $arg (@$info) { |
458 | next unless (reftype($arg)||'') eq 'HASH'; |
e666c5fd |
459 | %opts = %{ $merge->merge($arg, \%opts) }; |
b2e4d522 |
460 | } |
b2e4d522 |
461 | delete $opts{dsn}; |
462 | |
dcdf7b2c |
463 | if (@opts{qw/pool_type pool_args/}) { |
464 | $self->pool_type(delete $opts{pool_type}) |
465 | if $opts{pool_type}; |
466 | |
b88b85e7 |
467 | $self->pool_args( |
e666c5fd |
468 | $merge->merge((delete $opts{pool_args} || {}), $self->pool_args) |
b88b85e7 |
469 | ); |
dcdf7b2c |
470 | |
64ae1667 |
471 | ## Since we possibly changed the pool_args, we need to clear the current |
472 | ## pool object so that next time it is used it will be rebuilt. |
473 | $self->clear_pool; |
dcdf7b2c |
474 | } |
475 | |
476 | if (@opts{qw/balancer_type balancer_args/}) { |
477 | $self->balancer_type(delete $opts{balancer_type}) |
478 | if $opts{balancer_type}; |
479 | |
b88b85e7 |
480 | $self->balancer_args( |
e666c5fd |
481 | $merge->merge((delete $opts{balancer_args} || {}), $self->balancer_args) |
b88b85e7 |
482 | ); |
dcdf7b2c |
483 | |
67c43863 |
484 | $self->balancer($self->_build_balancer) |
6f7344b8 |
485 | if $self->balancer; |
dcdf7b2c |
486 | } |
487 | |
b2e4d522 |
488 | $self->_master_connect_info_opts(\%opts); |
489 | |
1abccf54 |
490 | return preserve_context { |
491 | $self->$next($info, @extra); |
492 | } after => sub { |
493 | # Make sure master is blessed into the correct class and apply role to it. |
494 | my $master = $self->master; |
495 | $master->_determine_driver; |
496 | Moose::Meta::Class->initialize(ref $master); |
cea43436 |
497 | |
1abccf54 |
498 | DBIx::Class::Storage::DBI::Replicated::WithDSN->meta->apply($master); |
0ce2d0d5 |
499 | |
1abccf54 |
500 | # link pool back to master |
501 | $self->pool->master($master); |
502 | }; |
b2e4d522 |
503 | }; |
504 | |
26ab719a |
505 | =head1 METHODS |
2bf79155 |
506 | |
26ab719a |
507 | This class defines the following methods. |
2bf79155 |
508 | |
c354902c |
509 | =head2 BUILDARGS |
2bf79155 |
510 | |
faaba25f |
511 | L<DBIx::Class::Schema> when instantiating its storage passed itself as the |
2ce6e9a6 |
512 | first argument. So we need to massage the arguments a bit so that all the |
513 | bits get put into the correct places. |
2bf79155 |
514 | |
515 | =cut |
516 | |
c354902c |
517 | sub BUILDARGS { |
fd323bf1 |
518 | my ($class, $schema, $storage_type_args, @args) = @_; |
d4daee7b |
519 | |
c354902c |
520 | return { |
6f7344b8 |
521 | schema=>$schema, |
522 | %$storage_type_args, |
523 | @args |
c354902c |
524 | } |
525 | } |
2bf79155 |
526 | |
cb6ec758 |
527 | =head2 _build_master |
2bf79155 |
528 | |
cb6ec758 |
529 | Lazy builder for the L</master> attribute. |
2bf79155 |
530 | |
531 | =cut |
532 | |
cb6ec758 |
533 | sub _build_master { |
2ce6e9a6 |
534 | my $self = shift @_; |
ee356d00 |
535 | my $master = DBIx::Class::Storage::DBI->new($self->schema); |
ee356d00 |
536 | $master |
106d5f3b |
537 | } |
538 | |
26ab719a |
539 | =head2 _build_pool |
2bf79155 |
540 | |
26ab719a |
541 | Lazy builder for the L</pool> attribute. |
2bf79155 |
542 | |
543 | =cut |
544 | |
26ab719a |
545 | sub _build_pool { |
64cdad22 |
546 | my $self = shift @_; |
547 | $self->create_pool(%{$self->pool_args}); |
2bf79155 |
548 | } |
549 | |
26ab719a |
550 | =head2 _build_balancer |
2bf79155 |
551 | |
cb6ec758 |
552 | Lazy builder for the L</balancer> attribute. This takes a Pool object so that |
553 | the balancer knows which pool it's balancing. |
2bf79155 |
554 | |
555 | =cut |
556 | |
26ab719a |
557 | sub _build_balancer { |
64cdad22 |
558 | my $self = shift @_; |
559 | $self->create_balancer( |
6f7344b8 |
560 | pool=>$self->pool, |
64cdad22 |
561 | master=>$self->master, |
562 | %{$self->balancer_args}, |
563 | ); |
2bf79155 |
564 | } |
565 | |
cb6ec758 |
566 | =head2 _build_write_handler |
2bf79155 |
567 | |
cb6ec758 |
568 | Lazy builder for the L</write_handler> attribute. The default is to set this to |
569 | the L</master>. |
50336325 |
570 | |
571 | =cut |
572 | |
cb6ec758 |
573 | sub _build_write_handler { |
64cdad22 |
574 | return shift->master; |
cb6ec758 |
575 | } |
50336325 |
576 | |
cb6ec758 |
577 | =head2 _build_read_handler |
2bf79155 |
578 | |
cb6ec758 |
579 | Lazy builder for the L</read_handler> attribute. The default is to set this to |
580 | the L</balancer>. |
2bf79155 |
581 | |
582 | =cut |
583 | |
cb6ec758 |
584 | sub _build_read_handler { |
64cdad22 |
585 | return shift->balancer; |
cb6ec758 |
586 | } |
50336325 |
587 | |
cb6ec758 |
588 | =head2 around: connect_replicants |
2bf79155 |
589 | |
cb6ec758 |
590 | All calls to connect_replicants needs to have an existing $schema tacked onto |
b2e4d522 |
591 | top of the args, since L<DBIx::Storage::DBI> needs it, and any C<connect_info> |
592 | options merged with the master, with replicant opts having higher priority. |
955a6df6 |
593 | |
cb6ec758 |
594 | =cut |
955a6df6 |
595 | |
b2e4d522 |
596 | around connect_replicants => sub { |
597 | my ($next, $self, @args) = @_; |
598 | |
599 | for my $r (@args) { |
600 | $r = [ $r ] unless reftype $r eq 'ARRAY'; |
601 | |
1a58752c |
602 | $self->throw_exception('coderef replicant connect_info not supported') |
b2e4d522 |
603 | if ref $r->[0] && reftype $r->[0] eq 'CODE'; |
604 | |
605 | # any connect_info options? |
606 | my $i = 0; |
607 | $i++ while $i < @$r && (reftype($r->[$i])||'') ne 'HASH'; |
608 | |
6f7344b8 |
609 | # make one if none |
b2e4d522 |
610 | $r->[$i] = {} unless $r->[$i]; |
611 | |
612 | # merge if two hashes |
b88b85e7 |
613 | my @hashes = @$r[$i .. $#{$r}]; |
614 | |
1a58752c |
615 | $self->throw_exception('invalid connect_info options') |
b88b85e7 |
616 | if (grep { reftype($_) eq 'HASH' } @hashes) != @hashes; |
617 | |
1a58752c |
618 | $self->throw_exception('too many hashrefs in connect_info') |
b88b85e7 |
619 | if @hashes > 2; |
620 | |
282a9a4f |
621 | my $merge = Hash::Merge->new('LEFT_PRECEDENT'); |
e666c5fd |
622 | my %opts = %{ $merge->merge(reverse @hashes) }; |
b88b85e7 |
623 | |
624 | # delete them |
b2e4d522 |
625 | splice @$r, $i+1, ($#{$r} - $i), (); |
626 | |
0bd8e058 |
627 | # make sure master/replicants opts don't clash |
628 | my %master_opts = %{ $self->_master_connect_info_opts }; |
629 | if (exists $opts{dbh_maker}) { |
630 | delete @master_opts{qw/dsn user password/}; |
631 | } |
632 | delete $master_opts{dbh_maker}; |
633 | |
b2e4d522 |
634 | # merge with master |
e666c5fd |
635 | %opts = %{ $merge->merge(\%opts, \%master_opts) }; |
b2e4d522 |
636 | |
637 | # update |
638 | $r->[$i] = \%opts; |
639 | } |
640 | |
641 | $self->$next($self->schema, @args); |
955a6df6 |
642 | }; |
2bf79155 |
643 | |
2bf79155 |
644 | =head2 all_storages |
645 | |
4a0eed52 |
646 | Returns an array of all the connected storage backends. The first element |
647 | in the returned array is the master, and the rest are each of the |
2bf79155 |
648 | replicants. |
649 | |
650 | =cut |
651 | |
652 | sub all_storages { |
64cdad22 |
653 | my $self = shift @_; |
654 | return grep {defined $_ && blessed $_} ( |
655 | $self->master, |
6412a592 |
656 | values %{ $self->replicants }, |
64cdad22 |
657 | ); |
2bf79155 |
658 | } |
659 | |
c4d3fae2 |
660 | =head2 execute_reliably ($coderef, ?@args) |
661 | |
662 | Given a coderef, saves the current state of the L</read_handler>, forces it to |
48580715 |
663 | use reliable storage (e.g. sets it to the master), executes a coderef and then |
c4d3fae2 |
664 | restores the original state. |
665 | |
666 | Example: |
667 | |
64cdad22 |
668 | my $reliably = sub { |
669 | my $name = shift @_; |
670 | $schema->resultset('User')->create({name=>$name}); |
fd323bf1 |
671 | my $user_rs = $schema->resultset('User')->find({name=>$name}); |
64cdad22 |
672 | return $user_rs; |
673 | }; |
c4d3fae2 |
674 | |
64cdad22 |
675 | my $user_rs = $schema->storage->execute_reliably($reliably, 'John'); |
c4d3fae2 |
676 | |
677 | Use this when you must be certain of your database state, such as when you just |
678 | inserted something and need to get a resultset including it, etc. |
679 | |
680 | =cut |
681 | |
682 | sub execute_reliably { |
1abccf54 |
683 | my $self = shift; |
684 | my $coderef = shift; |
d4daee7b |
685 | |
64cdad22 |
686 | unless( ref $coderef eq 'CODE') { |
687 | $self->throw_exception('Second argument must be a coderef'); |
688 | } |
d4daee7b |
689 | |
1abccf54 |
690 | ## replace the current read handler for the remainder of the scope |
691 | local $self->{read_handler} = $self->master; |
d4daee7b |
692 | |
1abccf54 |
693 | my $args = \@_; |
694 | return try { |
695 | $coderef->(@$args); |
ed7ab0f4 |
696 | } catch { |
697 | $self->throw_exception("coderef returned an error: $_"); |
64cdad22 |
698 | }; |
c4d3fae2 |
699 | } |
700 | |
cb6ec758 |
701 | =head2 set_reliable_storage |
702 | |
703 | Sets the current $schema to be 'reliable', that is all queries, both read and |
704 | write are sent to the master |
d4daee7b |
705 | |
cb6ec758 |
706 | =cut |
707 | |
708 | sub set_reliable_storage { |
64cdad22 |
709 | my $self = shift @_; |
710 | my $schema = $self->schema; |
711 | my $write_handler = $self->schema->storage->write_handler; |
d4daee7b |
712 | |
64cdad22 |
713 | $schema->storage->read_handler($write_handler); |
cb6ec758 |
714 | } |
715 | |
716 | =head2 set_balanced_storage |
717 | |
718 | Sets the current $schema to be use the </balancer> for all reads, while all |
48580715 |
719 | writes are sent to the master only |
d4daee7b |
720 | |
cb6ec758 |
721 | =cut |
722 | |
723 | sub set_balanced_storage { |
64cdad22 |
724 | my $self = shift @_; |
725 | my $schema = $self->schema; |
bd5da369 |
726 | my $balanced_handler = $self->schema->storage->balancer; |
d4daee7b |
727 | |
bd5da369 |
728 | $schema->storage->read_handler($balanced_handler); |
cb6ec758 |
729 | } |
2bf79155 |
730 | |
731 | =head2 connected |
732 | |
733 | Check that the master and at least one of the replicants is connected. |
734 | |
735 | =cut |
736 | |
737 | sub connected { |
64cdad22 |
738 | my $self = shift @_; |
739 | return |
740 | $self->master->connected && |
741 | $self->pool->connected_replicants; |
2bf79155 |
742 | } |
743 | |
2bf79155 |
744 | =head2 ensure_connected |
745 | |
746 | Make sure all the storages are connected. |
747 | |
748 | =cut |
749 | |
750 | sub ensure_connected { |
64cdad22 |
751 | my $self = shift @_; |
752 | foreach my $source ($self->all_storages) { |
753 | $source->ensure_connected(@_); |
754 | } |
2bf79155 |
755 | } |
756 | |
2bf79155 |
757 | =head2 limit_dialect |
758 | |
759 | Set the limit_dialect for all existing storages |
760 | |
761 | =cut |
762 | |
763 | sub limit_dialect { |
64cdad22 |
764 | my $self = shift @_; |
765 | foreach my $source ($self->all_storages) { |
766 | $source->limit_dialect(@_); |
767 | } |
f3e9f010 |
768 | return $self->master->limit_dialect; |
2bf79155 |
769 | } |
770 | |
2bf79155 |
771 | =head2 quote_char |
772 | |
773 | Set the quote_char for all existing storages |
774 | |
775 | =cut |
776 | |
777 | sub quote_char { |
64cdad22 |
778 | my $self = shift @_; |
779 | foreach my $source ($self->all_storages) { |
780 | $source->quote_char(@_); |
781 | } |
3fbe08e3 |
782 | return $self->master->quote_char; |
2bf79155 |
783 | } |
784 | |
2bf79155 |
785 | =head2 name_sep |
786 | |
787 | Set the name_sep for all existing storages |
788 | |
789 | =cut |
790 | |
791 | sub name_sep { |
64cdad22 |
792 | my $self = shift @_; |
793 | foreach my $source ($self->all_storages) { |
794 | $source->name_sep(@_); |
795 | } |
3fbe08e3 |
796 | return $self->master->name_sep; |
2bf79155 |
797 | } |
798 | |
2bf79155 |
799 | =head2 set_schema |
800 | |
801 | Set the schema object for all existing storages |
802 | |
803 | =cut |
804 | |
805 | sub set_schema { |
64cdad22 |
806 | my $self = shift @_; |
807 | foreach my $source ($self->all_storages) { |
808 | $source->set_schema(@_); |
809 | } |
2bf79155 |
810 | } |
811 | |
2bf79155 |
812 | =head2 debug |
813 | |
814 | set a debug flag across all storages |
815 | |
816 | =cut |
817 | |
818 | sub debug { |
64cdad22 |
819 | my $self = shift @_; |
3fbe08e3 |
820 | if(@_) { |
821 | foreach my $source ($self->all_storages) { |
822 | $source->debug(@_); |
6f7344b8 |
823 | } |
64cdad22 |
824 | } |
3fbe08e3 |
825 | return $self->master->debug; |
2bf79155 |
826 | } |
827 | |
2bf79155 |
828 | =head2 debugobj |
829 | |
cea43436 |
830 | set a debug object |
2bf79155 |
831 | |
832 | =cut |
833 | |
834 | sub debugobj { |
64cdad22 |
835 | my $self = shift @_; |
cea43436 |
836 | return $self->master->debugobj(@_); |
2bf79155 |
837 | } |
838 | |
2bf79155 |
839 | =head2 debugfh |
840 | |
cea43436 |
841 | set a debugfh object |
2bf79155 |
842 | |
843 | =cut |
844 | |
845 | sub debugfh { |
64cdad22 |
846 | my $self = shift @_; |
cea43436 |
847 | return $self->master->debugfh(@_); |
2bf79155 |
848 | } |
849 | |
2bf79155 |
850 | =head2 debugcb |
851 | |
cea43436 |
852 | set a debug callback |
2bf79155 |
853 | |
854 | =cut |
855 | |
856 | sub debugcb { |
64cdad22 |
857 | my $self = shift @_; |
cea43436 |
858 | return $self->master->debugcb(@_); |
2bf79155 |
859 | } |
860 | |
2bf79155 |
861 | =head2 disconnect |
862 | |
863 | disconnect everything |
864 | |
865 | =cut |
866 | |
867 | sub disconnect { |
64cdad22 |
868 | my $self = shift @_; |
869 | foreach my $source ($self->all_storages) { |
870 | $source->disconnect(@_); |
871 | } |
2bf79155 |
872 | } |
873 | |
b2e4d522 |
874 | =head2 cursor_class |
875 | |
876 | set cursor class on all storages, or return master's |
877 | |
878 | =cut |
879 | |
880 | sub cursor_class { |
881 | my ($self, $cursor_class) = @_; |
882 | |
883 | if ($cursor_class) { |
884 | $_->cursor_class($cursor_class) for $self->all_storages; |
885 | } |
886 | $self->master->cursor_class; |
887 | } |
d4daee7b |
888 | |
3244fdcc |
889 | =head2 cursor |
890 | |
891 | set cursor class on all storages, or return master's, alias for L</cursor_class> |
892 | above. |
893 | |
894 | =cut |
895 | |
896 | sub cursor { |
897 | my ($self, $cursor_class) = @_; |
898 | |
899 | if ($cursor_class) { |
900 | $_->cursor($cursor_class) for $self->all_storages; |
901 | } |
902 | $self->master->cursor; |
903 | } |
904 | |
905 | =head2 unsafe |
906 | |
907 | sets the L<DBIx::Class::Storage::DBI/unsafe> option on all storages or returns |
908 | master's current setting |
909 | |
910 | =cut |
911 | |
912 | sub unsafe { |
913 | my $self = shift; |
914 | |
915 | if (@_) { |
916 | $_->unsafe(@_) for $self->all_storages; |
917 | } |
918 | |
919 | return $self->master->unsafe; |
920 | } |
921 | |
922 | =head2 disable_sth_caching |
923 | |
924 | sets the L<DBIx::Class::Storage::DBI/disable_sth_caching> option on all storages |
925 | or returns master's current setting |
926 | |
927 | =cut |
928 | |
929 | sub disable_sth_caching { |
930 | my $self = shift; |
931 | |
932 | if (@_) { |
933 | $_->disable_sth_caching(@_) for $self->all_storages; |
934 | } |
935 | |
936 | return $self->master->disable_sth_caching; |
937 | } |
938 | |
939 | =head2 lag_behind_master |
940 | |
941 | returns the highest Replicant L<DBIx::Class::Storage::DBI/lag_behind_master> |
942 | setting |
943 | |
944 | =cut |
945 | |
946 | sub lag_behind_master { |
947 | my $self = shift; |
948 | |
949 | return max map $_->lag_behind_master, $self->replicants; |
fd323bf1 |
950 | } |
3244fdcc |
951 | |
952 | =head2 is_replicating |
953 | |
954 | returns true if all replicants return true for |
955 | L<DBIx::Class::Storage::DBI/is_replicating> |
956 | |
957 | =cut |
958 | |
959 | sub is_replicating { |
960 | my $self = shift; |
961 | |
962 | return (grep $_->is_replicating, $self->replicants) == ($self->replicants); |
963 | } |
964 | |
965 | =head2 connect_call_datetime_setup |
966 | |
967 | calls L<DBIx::Class::Storage::DBI/connect_call_datetime_setup> for all storages |
968 | |
969 | =cut |
970 | |
971 | sub connect_call_datetime_setup { |
972 | my $self = shift; |
973 | $_->connect_call_datetime_setup for $self->all_storages; |
974 | } |
975 | |
976 | sub _populate_dbh { |
977 | my $self = shift; |
978 | $_->_populate_dbh for $self->all_storages; |
979 | } |
980 | |
981 | sub _connect { |
982 | my $self = shift; |
983 | $_->_connect for $self->all_storages; |
984 | } |
985 | |
986 | sub _rebless { |
987 | my $self = shift; |
988 | $_->_rebless for $self->all_storages; |
989 | } |
990 | |
991 | sub _determine_driver { |
992 | my $self = shift; |
993 | $_->_determine_driver for $self->all_storages; |
994 | } |
995 | |
996 | sub _driver_determined { |
997 | my $self = shift; |
fd323bf1 |
998 | |
3244fdcc |
999 | if (@_) { |
1000 | $_->_driver_determined(@_) for $self->all_storages; |
1001 | } |
1002 | |
1003 | return $self->master->_driver_determined; |
1004 | } |
1005 | |
1006 | sub _init { |
1007 | my $self = shift; |
fd323bf1 |
1008 | |
3244fdcc |
1009 | $_->_init for $self->all_storages; |
1010 | } |
1011 | |
1012 | sub _run_connection_actions { |
1013 | my $self = shift; |
fd323bf1 |
1014 | |
3244fdcc |
1015 | $_->_run_connection_actions for $self->all_storages; |
1016 | } |
1017 | |
1018 | sub _do_connection_actions { |
1019 | my $self = shift; |
fd323bf1 |
1020 | |
3244fdcc |
1021 | if (@_) { |
1022 | $_->_do_connection_actions(@_) for $self->all_storages; |
1023 | } |
1024 | } |
1025 | |
1026 | sub connect_call_do_sql { |
1027 | my $self = shift; |
1028 | $_->connect_call_do_sql(@_) for $self->all_storages; |
1029 | } |
1030 | |
1031 | sub disconnect_call_do_sql { |
1032 | my $self = shift; |
1033 | $_->disconnect_call_do_sql(@_) for $self->all_storages; |
1034 | } |
1035 | |
1036 | sub _seems_connected { |
1037 | my $self = shift; |
1038 | |
1039 | return min map $_->_seems_connected, $self->all_storages; |
1040 | } |
1041 | |
1042 | sub _ping { |
1043 | my $self = shift; |
1044 | |
1045 | return min map $_->_ping, $self->all_storages; |
1046 | } |
1047 | |
bbdda281 |
1048 | # not using the normalized_version, because we want to preserve |
1049 | # version numbers much longer than the conventional xxx.yyyzzz |
7da56142 |
1050 | my $numify_ver = sub { |
1051 | my $ver = shift; |
1052 | my @numparts = split /\D+/, $ver; |
bbdda281 |
1053 | my $format = '%d.' . (join '', ('%06d') x (@numparts - 1)); |
7da56142 |
1054 | |
1055 | return sprintf $format, @numparts; |
1056 | }; |
fecb38cb |
1057 | sub _server_info { |
1058 | my $self = shift; |
1059 | |
bbdda281 |
1060 | if (not $self->_dbh_details->{info}) { |
1061 | $self->_dbh_details->{info} = ( |
fd323bf1 |
1062 | reduce { $a->[0] < $b->[0] ? $a : $b } |
7da56142 |
1063 | map [ $numify_ver->($_->{dbms_version}), $_ ], |
1064 | map $_->_server_info, $self->all_storages |
1065 | )->[1]; |
fecb38cb |
1066 | } |
1067 | |
bbdda281 |
1068 | return $self->next::method; |
fecb38cb |
1069 | } |
1070 | |
1071 | sub _get_server_version { |
1072 | my $self = shift; |
1073 | |
1074 | return $self->_server_info->{dbms_version}; |
1075 | } |
1076 | |
7e38d850 |
1077 | =head1 GOTCHAS |
1078 | |
1079 | Due to the fact that replicants can lag behind a master, you must take care to |
1080 | make sure you use one of the methods to force read queries to a master should |
1081 | you need realtime data integrity. For example, if you insert a row, and then |
47d7b769 |
1082 | immediately re-read it from the database (say, by doing $result->discard_changes) |
7e38d850 |
1083 | or you insert a row and then immediately build a query that expects that row |
1084 | to be an item, you should force the master to handle reads. Otherwise, due to |
1085 | the lag, there is no certainty your data will be in the expected state. |
1086 | |
1087 | For data integrity, all transactions automatically use the master storage for |
1088 | all read and write queries. Using a transaction is the preferred and recommended |
1089 | method to force the master to handle all read queries. |
1090 | |
1091 | Otherwise, you can force a single query to use the master with the 'force_pool' |
1092 | attribute: |
1093 | |
47d7b769 |
1094 | my $result = $resultset->search(undef, {force_pool=>'master'})->find($pk); |
7e38d850 |
1095 | |
1096 | This attribute will safely be ignore by non replicated storages, so you can use |
1097 | the same code for both types of systems. |
1098 | |
1099 | Lastly, you can use the L</execute_reliably> method, which works very much like |
1100 | a transaction. |
1101 | |
1102 | For debugging, you can turn replication on/off with the methods L</set_reliable_storage> |
1103 | and L</set_balanced_storage>, however this operates at a global level and is not |
1104 | suitable if you have a shared Schema object being used by multiple processes, |
1105 | such as on a web application server. You can get around this limitation by |
1106 | using the Schema clone method. |
1107 | |
1108 | my $new_schema = $schema->clone; |
1109 | $new_schema->set_reliable_storage; |
d4daee7b |
1110 | |
7e38d850 |
1111 | ## $new_schema will use only the Master storage for all reads/writes while |
1112 | ## the $schema object will use replicated storage. |
1113 | |
f5d3a5de |
1114 | =head1 AUTHOR |
1115 | |
64cdad22 |
1116 | John Napiorkowski <john.napiorkowski@takkle.com> |
f5d3a5de |
1117 | |
c4d3fae2 |
1118 | Based on code originated by: |
f5d3a5de |
1119 | |
f8213ab0 |
1120 | Norbert Csongrádi <bert@cpan.org> |
1121 | Peter Siklósi <einon@einon.hu> |
2156bbdd |
1122 | |
f5d3a5de |
1123 | =head1 LICENSE |
1124 | |
1125 | You may distribute this code under the same terms as Perl itself. |
1126 | |
1127 | =cut |
1128 | |
c354902c |
1129 | __PACKAGE__->meta->make_immutable; |
1130 | |
f5d3a5de |
1131 | 1; |