X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FDBIx%2FClass%2FStorage%2FDBI%2FReplicated.pm;h=a70a8b56c3d6910b63b3e4c103cfbd16c7d5df69;hb=161fb22350bdfb511af2cc96d2a556a4296c20e8;hp=d736c41a6cff4457f88b7df013c16aa5eb22645c;hpb=2156bbddf88e67ebe429789d0018c708cddfcbe4;p=dbsrgits%2FDBIx-Class.git diff --git a/lib/DBIx/Class/Storage/DBI/Replicated.pm b/lib/DBIx/Class/Storage/DBI/Replicated.pm index d736c41..a70a8b5 100644 --- a/lib/DBIx/Class/Storage/DBI/Replicated.pm +++ b/lib/DBIx/Class/Storage/DBI/Replicated.pm @@ -1,14 +1,12 @@ package DBIx::Class::Storage::DBI::Replicated; -use strict; -use warnings; - +use Moose; use DBIx::Class::Storage::DBI; -use DBD::Multi; - -use base qw/Class::Accessor::Fast/; +use DBIx::Class::Storage::DBI::Replicated::Pool; +use DBIx::Class::Storage::DBI::Replicated::Balancer; +use Scalar::Util qw(blessed); -__PACKAGE__->mk_accessors( qw/read_source write_source/ ); +extends 'DBIx::Class::Storage::DBI', 'Moose::Object'; =head1 NAME @@ -17,41 +15,21 @@ DBIx::Class::Storage::DBI::Replicated - ALPHA Replicated database support =head1 SYNOPSIS The Following example shows how to change an existing $schema to a replicated -storage type and update it's connection information to contain a master DSN and -an array of slaves. +storage type, add some replicated (readonly) databases, and perform reporting +tasks. ## Change storage_type in your schema class - $schema->storage_type( '::DBI::Replicated' ); + $schema->storage_type( ['::DBI::Replicated', {balancer=>'::Random'}] ); + + ## Add some slaves. Basically this is an array of arrayrefs, where each + ## arrayref is database connect information - ## Set your connection. - $schema->connect( - $dsn, $user, $password, { - AutoCommit => 1, - ## Other standard DBI connection or DBD custom attributes added as - ## usual. Additionally, we have two custom attributes for defining - ## slave information and controlling how the underlying DBD::Multi - slaves_connect_info => [ - ## Define each slave like a 'normal' DBI connection, but you add - ## in a DBD::Multi custom attribute to define how the slave is - ## prioritized. Please see DBD::Multi for more. - [$slave1dsn, $user, $password, {%slave1opts, priority=>10}], - [$slave2dsn, $user, $password, {%slave2opts, priority=>10}], - [$slave3dsn, $user, $password, {%slave3opts, priority=>20}], - ## add in a preexisting database handle - [$dbh, '','', {priority=>30}], - ## DBD::Multi will call this coderef for connects - [sub { DBI->connect(< DSN info >) }, '', '', {priority=>40}], - ## If the last item is hashref, we use that for DBD::Multi's - ## configuration information. Again, see DBD::Multi for more. - {timeout=>25, failed_max=>2}, - ], - }, + $schema->storage->connect_replicants( + [$dsn1, $user, $pass, \%opts], + [$dsn1, $user, $pass, \%opts], + [$dsn1, $user, $pass, \%opts], ); - ## Now, just use the schema as normal - $schema->resultset('Table')->find(< unique >); ## Reads will use slaves - $schema->resultset('Table')->create(\%info); ## Writes will use master - =head1 DESCRIPTION Warning: This class is marked ALPHA. We are using this in development and have @@ -64,203 +42,486 @@ one master and numerous slave database connections. All write-type queries (INSERT, UPDATE, DELETE and even LAST_INSERT_ID) are routed to master database, all read-type queries (SELECTs) go to the slave database. -For every slave database you can define a priority value, which controls data -source usage pattern. It uses L, so first the lower priority data -sources used (if they have the same priority, the are used randomized), than -if all low priority data sources fail, higher ones tried in order. +Basically, any method request that L would normally +handle gets delegated to one of the two attributes: L or to +L. Additionally, some methods need to be distributed +to all existing storages. This way our storage class is a drop in replacement +for L. + +Read traffic is spread across the replicants (slaves) occuring to a user +selected algorithm. The default algorithm is random weighted. + +TODO more details about the algorithm. -=head1 CONFIGURATION +=head1 ATTRIBUTES -Please see L for most configuration information. +This class defines the following attributes. + +=head2 pool_type + +Contains the classname which will instantiate the L object. Defaults +to: L. =cut -sub new { - my $proto = shift; - my $class = ref( $proto ) || $proto; - my $self = {}; +has 'pool_type' => ( + is=>'ro', + isa=>'ClassName', + lazy_build=>1, + handles=>{ + 'create_pool' => 'new', + }, +); - bless( $self, $class ); +=head2 balancer_type - $self->write_source( DBIx::Class::Storage::DBI->new ); - $self->read_source( DBIx::Class::Storage::DBI->new ); +The replication pool requires a balance class to provider the methods for +choose how to spread the query load across each replicant in the pool. - return $self; -} +=cut -sub all_sources { - my $self = shift; +has 'balancer_type' => ( + is=>'ro', + isa=>'ClassName', + lazy_build=>1, + handles=>{ + 'create_balancer' => 'new', + }, +); - my @sources = ($self->read_source, $self->write_source); +=head2 balancer_args - return wantarray ? @sources : \@sources; -} +Contains a hashref of initialized information to pass to the Balancer object. +See L for available arguments. -sub _connect_info { - my $self = shift; - my $master = $self->write_source->_connect_info; - $master->[-1]->{slave_connect_info} = $self->read_source->_connect_info; - return $master; -} +=cut -sub connect_info { - my ($self, $source_info) = @_; +has 'balancer_args' => ( + is=>'ro', + isa=>'HashRef', +); - ## if there is no $source_info, treat this sub like an accessor - return $self->_connect_info - if !$source_info; - - ## Alright, let's conect the master - $self->write_source->connect_info($source_info); - - ## Now, build and then connect the Slaves - my @slaves_connect_info = @{$source_info->[-1]->{slaves_connect_info}}; - my $dbd_multi_config = ref $slaves_connect_info[-1] eq 'HASH' - ? pop @slaves_connect_info : {}; - - ## We need to do this since SQL::Abstract::Limit can't guess what DBD::Multi is - $dbd_multi_config->{limit_dialect} = $self->write_source->sql_maker->limit_dialect - unless defined $dbd_multi_config->{limit_dialect}; - - @slaves_connect_info = map { - ## if the first element in the arrayhash is a ref, make that the value - my $db = ref $_->[0] ? $_->[0] : $_; - my $priority = $_->[-1]->{priority} || 10; ## default priority is 10 - $priority => $db; - } @slaves_connect_info; +=head2 pool + +Is a or derived class. This is a +container class for one or more replicated databases. + +=cut + +has 'pool' => ( + is=>'ro', + isa=>'DBIx::Class::Storage::DBI::Replicated::Pool', + lazy_build=>1, + handles=>[qw/ + connect_replicants + replicants + has_replicants + /], +); + +=head2 balancer + +Is a or derived class. This +is a class that takes a pool () + +=cut + +has 'balancer' => ( + is=>'ro', + isa=>'DBIx::Class::Storage::DBI::Replicated::Balancer', + lazy_build=>1, + handles=>[qw/auto_validate_every/], +); + +=head2 master + +The master defines the canonical state for a pool of connected databases. All +the replicants are expected to match this databases state. Thus, in a classic +Master / Slaves distributed system, all the slaves are expected to replicate +the Master's state as quick as possible. This is the only database in the +pool of databases that is allowed to handle write traffic. + +=cut + +has 'master' => ( + is=> 'ro', + isa=>'DBIx::Class::Storage::DBI', + lazy_build=>1, +); + +=head1 ATTRIBUTES IMPLEMENTING THE DBIx::Storage::DBI INTERFACE + +The following methods are delegated all the methods required for the +L interface. + +=head2 read_handler + +Defines an object that implements the read side of L. + +=cut + +has 'read_handler' => ( + is=>'rw', + isa=>'Object', + lazy_build=>1, + handles=>[qw/ + select + select_single + columns_info_for + /], +); + +=head2 write_handler + +Defines an object that implements the write side of L. + +=cut + +has 'write_handler' => ( + is=>'ro', + isa=>'Object', + lazy_build=>1, + lazy_build=>1, + handles=>[qw/ + on_connect_do + on_disconnect_do + connect_info + throw_exception + sql_maker + sqlt_type + create_ddl_dir + deployment_statements + datetime_parser + datetime_parser_type + last_insert_id + insert + insert_bulk + update + delete + dbh + txn_do + txn_commit + txn_rollback + sth + deploy + schema + /], +); + +=head1 METHODS + +This class defines the following methods. + +=head2 new + +L when instantiating it's storage passed itself as the +first argument. We need to invoke L on the underlying parent class, make +sure we properly give it a L meta class, and then correctly instantiate +our attributes. Basically we pass on whatever the schema has in it's class +data for 'storage_type_args' to our replicated storage type. + +=cut + +sub new { + my $class = shift @_; + my $schema = shift @_; + my $storage_type_args = shift @_; + my $obj = $class->SUPER::new($schema, $storage_type_args, @_); - $self->read_source->connect_info([ - 'dbi:Multi:', undef, undef, { - dsns => [@slaves_connect_info], - %$dbd_multi_config, - }, - ]); + ## Hate to do it this way, but can't seem to get advice on the attribute working right + ## maybe we can do a type and coercion for it. + if( $storage_type_args->{balancer_type} && $storage_type_args->{balancer_type}=~m/^::/) { + $storage_type_args->{balancer_type} = 'DBIx::Class::Storage::DBI::Replicated::Balancer'.$storage_type_args->{balancer_type}; + eval "require $storage_type_args->{balancer_type}"; + } - ## Return the formated connection information - return $self->_connect_info; + return $class->meta->new_object( + __INSTANCE__ => $obj, + %$storage_type_args, + @_, + ); } -sub select { - shift->read_source->select( @_ ); -} -sub select_single { - shift->read_source->select_single( @_ ); -} -sub throw_exception { - shift->read_source->throw_exception( @_ ); -} -sub sql_maker { - shift->read_source->sql_maker( @_ ); -} -sub columns_info_for { - shift->read_source->columns_info_for( @_ ); -} -sub sqlt_type { - shift->read_source->sqlt_type( @_ ); -} -sub create_ddl_dir { - shift->read_source->create_ddl_dir( @_ ); -} -sub deployment_statements { - shift->read_source->deployment_statements( @_ ); -} -sub datetime_parser { - shift->read_source->datetime_parser( @_ ); -} -sub datetime_parser_type { - shift->read_source->datetime_parser_type( @_ ); -} -sub build_datetime_parser { - shift->read_source->build_datetime_parser( @_ ); -} +=head2 _build_master -sub limit_dialect { $_->limit_dialect( @_ ) for( shift->all_sources ) } -sub quote_char { $_->quote_char( @_ ) for( shift->all_sources ) } -sub name_sep { $_->quote_char( @_ ) for( shift->all_sources ) } -sub disconnect { $_->disconnect( @_ ) for( shift->all_sources ) } -sub set_schema { $_->set_schema( @_ ) for( shift->all_sources ) } +Lazy builder for the L attribute. -sub DESTROY { - my $self = shift; +=cut - undef $self->{write_source}; - undef $self->{read_sources}; +sub _build_master { + DBIx::Class::Storage::DBI->new; } -sub last_insert_id { - shift->write_source->last_insert_id( @_ ); +=head2 _build_pool_type + +Lazy builder for the L attribute. + +=cut + +sub _build_pool_type { + return 'DBIx::Class::Storage::DBI::Replicated::Pool'; } -sub insert { - shift->write_source->insert( @_ ); + +=head2 _build_pool + +Lazy builder for the L attribute. + +=cut + +sub _build_pool { + my $self = shift @_; + $self->create_pool; } -sub update { - shift->write_source->update( @_ ); + +=head2 _build_balancer_type + +Lazy builder for the L attribute. + +=cut + +sub _build_balancer_type { + return 'DBIx::Class::Storage::DBI::Replicated::Balancer::First'; } -sub update_all { - shift->write_source->update_all( @_ ); + +=head2 _build_balancer + +Lazy builder for the L attribute. This takes a Pool object so that +the balancer knows which pool it's balancing. + +=cut + +sub _build_balancer { + my $self = shift @_; + $self->create_balancer( + pool=>$self->pool, + master=>$self->master, + %{$self->balancer_args},); } -sub delete { - shift->write_source->delete( @_ ); + +=head2 _build_write_handler + +Lazy builder for the L attribute. The default is to set this to +the L. + +=cut + +sub _build_write_handler { + return shift->master; } -sub delete_all { - shift->write_source->delete_all( @_ ); + +=head2 _build_read_handler + +Lazy builder for the L attribute. The default is to set this to +the L. + +=cut + +sub _build_read_handler { + return shift->balancer; } -sub create { - shift->write_source->create( @_ ); + +=head2 around: connect_replicants + +All calls to connect_replicants needs to have an existing $schema tacked onto +top of the args, since L needs it. + +=cut + +around 'connect_replicants' => sub { + my ($method, $self, @args) = @_; + $self->$method($self->schema, @args); +}; + +=head2 all_storages + +Returns an array of of all the connected storage backends. The first element +in the returned array is the master, and the remainings are each of the +replicants. + +=cut + +sub all_storages { + my $self = shift @_; + + return grep {defined $_ && blessed $_} ( + $self->master, + $self->replicants, + ); } -sub find_or_create { - shift->write_source->find_or_create( @_ ); + +=head2 set_reliable_storage + +Sets the current $schema to be 'reliable', that is all queries, both read and +write are sent to the master + +=cut + +sub set_reliable_storage { + my $self = shift @_; + my $schema = $self->schema; + my $write_handler = $self->schema->storage->write_handler; + + $schema->storage->read_handler($write_handler); } -sub update_or_create { - shift->write_source->update_or_create( @_ ); + +=head2 set_balanced_storage + +Sets the current $schema to be use the for all reads, while all +writea are sent to the master only + +=cut + +sub set_balanced_storage { + my $self = shift @_; + my $schema = $self->schema; + my $write_handler = $self->schema->storage->balancer; + + $schema->storage->read_handler($write_handler); } + +=head2 connected + +Check that the master and at least one of the replicants is connected. + +=cut + sub connected { - shift->write_source->connected( @_ ); + my $self = shift @_; + + return + $self->master->connected && + $self->pool->connected_replicants; } + +=head2 ensure_connected + +Make sure all the storages are connected. + +=cut + sub ensure_connected { - shift->write_source->ensure_connected( @_ ); -} -sub dbh { - shift->write_source->dbh( @_ ); -} -sub txn_do { - shift->write_source->txn_do( @_ ); + my $self = shift @_; + foreach my $source ($self->all_storages) { + $source->ensure_connected(@_); + } } -sub txn_commit { - shift->write_source->txn_commit( @_ ); + +=head2 limit_dialect + +Set the limit_dialect for all existing storages + +=cut + +sub limit_dialect { + my $self = shift @_; + foreach my $source ($self->all_storages) { + $source->limit_dialect(@_); + } } -sub txn_rollback { - shift->write_source->txn_rollback( @_ ); + +=head2 quote_char + +Set the quote_char for all existing storages + +=cut + +sub quote_char { + my $self = shift @_; + foreach my $source ($self->all_storages) { + $source->quote_char(@_); + } } -sub sth { - shift->write_source->sth( @_ ); + +=head2 name_sep + +Set the name_sep for all existing storages + +=cut + +sub name_sep { + my $self = shift @_; + foreach my $source ($self->all_storages) { + $source->name_sep(@_); + } } -sub deploy { - shift->write_source->deploy( @_ ); + +=head2 set_schema + +Set the schema object for all existing storages + +=cut + +sub set_schema { + my $self = shift @_; + foreach my $source ($self->all_storages) { + $source->set_schema(@_); + } } -sub _prep_for_execute { - shift->write_source->_prep_for_execute(@_); + +=head2 debug + +set a debug flag across all storages + +=cut + +sub debug { + my $self = shift @_; + foreach my $source ($self->all_storages) { + $source->debug(@_); + } } +=head2 debugobj + +set a debug object across all storages + +=cut + sub debugobj { - shift->write_source->debugobj(@_); + my $self = shift @_; + foreach my $source ($self->all_storages) { + $source->debugobj(@_); + } } -sub debug { - shift->write_source->debug(@_); + +=head2 debugfh + +set a debugfh object across all storages + +=cut + +sub debugfh { + my $self = shift @_; + foreach my $source ($self->all_storages) { + $source->debugfh(@_); + } } -sub debugfh { shift->_not_supported( 'debugfh' ) }; -sub debugcb { shift->_not_supported( 'debugcb' ) }; +=head2 debugcb + +set a debug callback across all storages -sub _not_supported { - my( $self, $method ) = @_; +=cut - die "This Storage does not support $method method."; +sub debugcb { + my $self = shift @_; + foreach my $source ($self->all_storages) { + $source->debugcb(@_); + } } -=head1 SEE ALSO +=head2 disconnect + +disconnect everything -L, L, L +=cut + +sub disconnect { + my $self = shift @_; + foreach my $source ($self->all_storages) { + $source->disconnect(@_); + } +} =head1 AUTHOR