The Following example shows how to change an existing $schema to a replicated
storage type, add some replicated (readonly) databases, and perform reporting
-tasks
+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
- $schema->storage->create_replicants(
+ $schema->storage->connect_replicants(
[$dsn1, $user, $pass, \%opts],
[$dsn1, $user, $pass, \%opts],
[$dsn1, $user, $pass, \%opts],
- ## This is just going to use the standard DBIC connect method, so it
- ## supports everything that method supports, such as connecting to an
- ## existing database handle.
- [$dbh],
);
-
=head1 DESCRIPTION
This class defines the following attributes.
-=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,
- 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
- /],
-);
-
-
-=head2 current_replicant
-
-Replicant storages (slaves) handle all read only traffic. The assumption is
-that your database will become readbound well before it becomes write bound
-and that being able to spread your read only traffic around to multiple
-databases is going to help you to scale traffic.
-
-This attribute returns the next slave to handle a read request. Your L</pool>
-attribute has methods to help you shuffle through all the available replicants
-via it's balancer object.
-
-This attribute defines the following reader/writer methods
-
-=over 4
-
-=item get_current_replicant
-
-Returns the contained L<DBIx::Class::Storage::DBI> replicant
-
-=item set_current_replicant
-
-Set the attribute to a given L<DBIx::Class::Storage::DBI> (or subclass) object.
-
-=back
-
-We split the reader/writer to make it easier to selectively override how the
-replicant is altered.
-
-=cut
-
-has 'current_replicant' => (
- is=> 'rw',
- reader=>'get_current_replicant',
- writer=>'set_current_replicant',
- isa=>'DBIx::Class::Storage::DBI',
- lazy_build=>1,
- handles=>[qw/
- select
- select_single
- columns_info_for
- /],
-);
-
-
=head2 pool_type
Contains the classname which will instantiate the L</pool> object. Defaults
has 'pool_type' => (
is=>'ro',
isa=>'ClassName',
- required=>1,
- lazy=>1,
- default=>'DBIx::Class::Storage::DBI::Replicated::Pool',
+ lazy_build=>1,
handles=>{
'create_pool' => 'new',
},
);
-
=head2 balancer_type
The replication pool requires a balance class to provider the methods for
has 'balancer_type' => (
is=>'ro',
isa=>'ClassName',
- required=>1,
- lazy=>1,
- default=>'DBIx::Class::Storage::DBI::Replicated::Balancer',
+ lazy_build=>1,
handles=>{
'create_balancer' => 'new',
},
);
-
=head2 pool
Is a <DBIx::Class::Storage::DBI::Replicated::Pool> or derived class. This is a
isa=>'DBIx::Class::Storage::DBI::Replicated::Pool',
lazy_build=>1,
handles=>[qw/
+ connect_replicants
replicants
has_replicants
- create_replicants
num_replicants
delete_replicant
/],
);
-
=head2 balancer
Is a <DBIx::Class::Storage::DBI::Replicated::Balancer> or derived class. This
is=>'ro',
isa=>'DBIx::Class::Storage::DBI::Replicated::Balancer',
lazy_build=>1,
- handles=>[qw/next_storage/],
+);
+
+=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<DBIx::Class::Storage::DBI> interface.
+
+=head2 read_handler
+
+Defines an object that implements the read side of L<BIx::Class::Storage::DBI>.
+
+=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<BIx::Class::Storage::DBI>.
+
+=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<DBIx::Class::Schema> when instantiating it's storage passed itself as the
+first argument. We need to invoke L</new> on the underlying parent class, make
+sure we properly give it a L<Moose> 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, @_);
+
+ ## 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 $class->meta->new_object(
+ __INSTANCE__ => $obj,
+ %$storage_type_args,
+ @_,
+ );
+}
+
=head2 _build_master
Lazy builder for the L</master> attribute.
DBIx::Class::Storage::DBI->new;
}
+=head2 _build_pool_type
-=head2 _build_current_replicant
-
-Lazy builder for the L</current_replicant_storage> attribute.
+Lazy builder for the L</pool_type> attribute.
=cut
-sub _build_current_replicant {
- my $self = shift @_;
- $self->next_storage($self->pool);
+sub _build_pool_type {
+ return 'DBIx::Class::Storage::DBI::Replicated::Pool';
}
-
=head2 _build_pool
Lazy builder for the L</pool> attribute.
=cut
sub _build_pool {
- my $self = shift @_;
- $self->create_pool;
+ shift->create_pool;
}
+=head2 _build_balancer_type
+
+Lazy builder for the L</balancer_type> attribute.
+
+=cut
+
+sub _build_balancer_type {
+ return 'DBIx::Class::Storage::DBI::Replicated::Balancer';
+}
=head2 _build_balancer
-Lazy builder for the L</balancer> attribute.
+Lazy builder for the L</balancer> 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;
+ $self->create_balancer(
+ pool=>$self->pool,
+ master=>$self->master);
}
+=head2 _build_write_handler
-=head2 around: create_replicants
-
-All calls to create_replicants needs to have an existing $schema tacked onto
-top of the args
+Lazy builder for the L</write_handler> attribute. The default is to set this to
+the L</master>.
=cut
-around 'create_replicants' => sub {
- my ($method, $self, @args) = @_;
- $self->$method($self->schema, @args);
-};
-
+sub _build_write_handler {
+ return shift->master;
+}
-=head2 after: get_current_replicant_storage
+=head2 _build_read_handler
-Advice on the current_replicant_storage attribute. Each time we use a replicant
-we need to change it via the storage pool algorithm. That way we are spreading
-the load evenly (hopefully) across existing capacity.
+Lazy builder for the L</read_handler> attribute. The default is to set this to
+the L</balancer>.
=cut
-after 'current_replicant' => sub {
- my $self = shift @_;
- my $next_replicant = $self->next_storage($self->pool);
+sub _build_read_handler {
+ return shift->balancer;
+}
-warn '......................';
- $self->set_current_replicant($next_replicant);
-};
+=head2 around: connect_replicants
+
+All calls to connect_replicants needs to have an existing $schema tacked onto
+top of the args, since L<DBIx::Storage::DBI> needs it.
+
+=cut
+around 'connect_replicants' => sub {
+ my ($method, $self, @args) = @_;
+ $self->$method($self->schema, @args);
+};
=head2 all_storages
);
}
+=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);
+}
+
+=head2 set_balanced_storage
+
+Sets the current $schema to be use the </balancer> 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
$self->pool->connected_replicants;
}
-
=head2 ensure_connected
Make sure all the storages are connected.
}
}
-
=head2 limit_dialect
Set the limit_dialect for all existing storages
}
}
-
=head2 quote_char
Set the quote_char for all existing storages
}
}
-
=head2 name_sep
Set the name_sep for all existing storages
}
}
-
=head2 set_schema
Set the schema object for all existing storages
}
}
-
=head2 debug
set a debug flag across all storages
}
}
-
=head2 debugobj
set a debug object across all storages
}
}
-
=head2 debugfh
set a debugfh object across all storages
}
}
-
=head2 debugcb
set a debug callback across all storages
}
}
-
=head2 disconnect
disconnect everything
}
}
-
-=head2 DESTROY
-
-Make sure we pass destroy events down to the storage handlers
-
-=cut
-
-sub DESTROY {
- my $self = shift;
- ## TODO, maybe we can just leave this alone ???
-}
-
-
-=head1 AUTHOR
-
-Norbert Csongrádi <bert@cpan.org>
-
-Peter Siklósi <einon@einon.hu>
-
-John Napiorkowski <john.napiorkowski@takkle.com>
-
-=head1 LICENSE
-
-You may distribute this code under the same terms as Perl itself.
-
-=cut
-
-1;
-
-__END__
-
-use strict;
-use warnings;
-
-use DBIx::Class::Storage::DBI;
-use DBD::Multi;
-
-use base qw/Class::Accessor::Fast/;
-
-__PACKAGE__->mk_accessors( qw/read_source write_source/ );
-
-=head1 NAME
-
-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.
-
- ## Change storage_type in your schema class
- $schema->storage_type( '::DBI::Replicated' );
-
- ## 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},
- ],
- },
- );
-
- ## 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
-some basic test coverage but the code hasn't yet been stressed by a variety
-of databases. Individual DB's may have quirks we are not aware of. Please
-use this in development and pass along your experiences/bug fixes.
-
-This class implements replicated data store for DBI. Currently you can define
-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<DBD::Multi>, 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.
-
-=head1 CONFIGURATION
-
-Please see L<DBD::Multi> for most configuration information.
-
-=cut
-
-sub new {
- my $proto = shift;
- my $class = ref( $proto ) || $proto;
- my $self = {};
-
- bless( $self, $class );
-
- $self->write_source( DBIx::Class::Storage::DBI->new );
- $self->read_source( DBIx::Class::Storage::DBI->new );
-
- return $self;
-}
-
-sub all_sources {
- my $self = shift;
-
- my @sources = ($self->read_source, $self->write_source);
-
- return wantarray ? @sources : \@sources;
-}
-
-sub _connect_info {
- my $self = shift;
- my $master = $self->write_source->_connect_info;
- $master->[-1]->{slave_connect_info} = $self->read_source->_connect_info;
- return $master;
-}
-
-sub connect_info {
- my ($self, $source_info) = @_;
-
- ## 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;
-
- $self->read_source->connect_info([
- 'dbi:Multi:', undef, undef, {
- dsns => [@slaves_connect_info],
- %$dbd_multi_config,
- },
- ]);
-
- ## Return the formated connection information
- return $self->_connect_info;
-}
-
-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( @_ );
-}
-
-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 ) }
-
-sub DESTROY {
- my $self = shift;
-
- undef $self->{write_source};
- undef $self->{read_sources};
-}
-
-sub last_insert_id {
- shift->write_source->last_insert_id( @_ );
-}
-sub insert {
- shift->write_source->insert( @_ );
-}
-sub update {
- shift->write_source->update( @_ );
-}
-sub update_all {
- shift->write_source->update_all( @_ );
-}
-sub delete {
- shift->write_source->delete( @_ );
-}
-sub delete_all {
- shift->write_source->delete_all( @_ );
-}
-sub create {
- shift->write_source->create( @_ );
-}
-sub find_or_create {
- shift->write_source->find_or_create( @_ );
-}
-sub update_or_create {
- shift->write_source->update_or_create( @_ );
-}
-sub connected {
- shift->write_source->connected( @_ );
-}
-sub ensure_connected {
- shift->write_source->ensure_connected( @_ );
-}
-sub dbh {
- shift->write_source->dbh( @_ );
-}
-sub txn_do {
- shift->write_source->txn_do( @_ );
-}
-sub txn_commit {
- shift->write_source->txn_commit( @_ );
-}
-sub txn_rollback {
- shift->write_source->txn_rollback( @_ );
-}
-sub sth {
- shift->write_source->sth( @_ );
-}
-sub deploy {
- shift->write_source->deploy( @_ );
-}
-sub _prep_for_execute {
- shift->write_source->_prep_for_execute(@_);
-}
-
-sub debugobj {
- shift->write_source->debugobj(@_);
-}
-sub debug {
- shift->write_source->debug(@_);
-}
-
-sub debugfh { shift->_not_supported( 'debugfh' ) };
-sub debugcb { shift->_not_supported( 'debugcb' ) };
-
-sub _not_supported {
- my( $self, $method ) = @_;
-
- die "This Storage does not support $method method.";
-}
-
-=head1 SEE ALSO
-
-L<DBI::Class::Storage::DBI>, L<DBD::Multi>, L<DBI>
-
=head1 AUTHOR
Norbert Csongrádi <bert@cpan.org>
projects / dbsrgits/DBIx-Class.git / blobdiff