BEGIN {
use Carp::Clan qw/^DBIx::Class/;
-
+
## Modules required for Replication support not required for general DBIC
## use, so we explicitly test for these.
-
+
my %replication_required = (
'Moose' => '0.77',
'MooseX::AttributeHelpers' => '0.12',
'namespace::clean' => '0.11',
'Hash::Merge' => '0.11'
);
-
+
my @didnt_load;
-
+
for my $module (keys %replication_required) {
eval "use $module $replication_required{$module}";
push @didnt_load, "$module $replication_required{$module}"
if $@;
}
-
+
croak("@{[ join ', ', @didnt_load ]} are missing and are required for Replication")
- if @didnt_load;
+ if @didnt_load;
}
use Moose;
use DBIx::Class::Storage::DBI;
use DBIx::Class::Storage::DBI::Replicated::Pool;
use DBIx::Class::Storage::DBI::Replicated::Balancer;
-use DBIx::Class::Storage::DBI::Replicated::Types 'BalancerClassNamePart';
+use DBIx::Class::Storage::DBI::Replicated::Types qw/BalancerClassNamePart DBICSchema DBICStorageDBI/;
use MooseX::Types::Moose qw/ClassName HashRef Object/;
use Scalar::Util 'reftype';
use Carp::Clan qw/^DBIx::Class/;
storage type, add some replicated (readonly) databases, and perform reporting
tasks.
- ## Change storage_type in your schema class
+You should set the 'storage_type attribute to a replicated type. You should
+also define your arguments, such as which balancer you want and any arguments
+that the Pool object should get.
+
$schema->storage_type( ['::DBI::Replicated', {balancer=>'::Random'}] );
-
- ## Add some slaves. Basically this is an array of arrayrefs, where each
- ## arrayref is database connect information
-
+
+Next, you need to add in the Replicants. Basically this is an array of
+arrayrefs, where each arrayref is database connect information. Think of these
+arguments as what you'd pass to the 'normal' $schema->connect method.
+
$schema->storage->connect_replicants(
[$dsn1, $user, $pass, \%opts],
[$dsn2, $user, $pass, \%opts],
[$dsn3, $user, $pass, \%opts],
);
-
- ## Now, just use the $schema as normal
+
+Now, just use the $schema as you normally would. Automatically all reads will
+be delegated to the replicants, while writes to the master.
+
$schema->resultset('Source')->search({name=>'etc'});
-
- ## You can force a given query to use a particular storage using the search
- ### attribute 'force_pool'. For example:
-
+
+You can force a given query to use a particular storage using the search
+attribute 'force_pool'. For example:
+
my $RS = $schema->resultset('Source')->search(undef, {force_pool=>'master'});
-
- ## Now $RS will force everything (both reads and writes) to use whatever was
- ## setup as the master storage. 'master' is hardcoded to always point to the
- ## Master, but you can also use any Replicant name. Please see:
- ## L<DBIx::Class::Storage::Replicated::Pool> and the replicants attribute for
- ## More. Also see transactions and L</execute_reliably> for alternative ways
- ## to force read traffic to the master.
-
+
+Now $RS will force everything (both reads and writes) to use whatever was setup
+as the master storage. 'master' is hardcoded to always point to the Master,
+but you can also use any Replicant name. Please see:
+L<DBIx::Class::Storage::DBI::Replicated::Pool> and the replicants attribute for more.
+
+Also see transactions and L</execute_reliably> for alternative ways to
+force read traffic to the master. In general, you should wrap your statements
+in a transaction when you are reading and writing to the same tables at the
+same time, since your replicants will often lag a bit behind the master.
+
+See L<DBIx::Class::Storage::DBI::Replicated::Instructions> for more help and
+walkthroughs.
+
=head1 DESCRIPTION
Warning: This class is marked BETA. This has been running a production
MooseX::Types => 0.10
namespace::clean => 0.11
Hash::Merge => 0.11
-
+
You will need to install these modules manually via CPAN or make them part of the
Makefile for your distribution.
has 'schema' => (
is=>'rw',
- isa=>'DBIx::Class::Schema',
+ isa=>DBICSchema,
weak_ref=>1,
required=>1,
);
=head2 pool_args
Contains a hashref of initialized information to pass to the Balancer object.
-See L<DBIx::Class::Storage::Replicated::Pool> for available arguments.
+See L<DBIx::Class::Storage::DBI::Replicated::Pool> for available arguments.
=cut
=head2 balancer_args
Contains a hashref of initialized information to pass to the Balancer object.
-See L<DBIx::Class::Storage::Replicated::Balancer> for available arguments.
+See L<DBIx::Class::Storage::DBI::Replicated::Balancer> for available arguments.
=cut
has 'master' => (
is=> 'ro',
- isa=>'DBIx::Class::Storage::DBI',
+ isa=>DBICStorageDBI,
lazy_build=>1,
);
sub BUILDARGS {
my ($class, $schema, $storage_type_args, @args) = @_;
-
+
return {
schema=>$schema,
%$storage_type_args,
sub execute_reliably {
my ($self, $coderef, @args) = @_;
-
+
unless( ref $coderef eq 'CODE') {
$self->throw_exception('Second argument must be a coderef');
}
-
+
##Get copy of master storage
my $master = $self->master;
-
+
##Get whatever the current read hander is
my $current = $self->read_handler;
-
+
##Set the read handler to master
$self->read_handler($master);
-
+
## do whatever the caller needs
my @result;
my $want_array = wantarray;
-
+
eval {
if($want_array) {
@result = $coderef->(@args);
$coderef->(@args);
}
};
-
+
##Reset to the original state
$self->read_handler($current);
-
+
##Exception testing has to come last, otherwise you might leave the
##read_handler set to master.
-
+
if($@) {
$self->throw_exception("coderef returned an error: $@");
} else {
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);
}
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 $balanced_handler = $self->schema->storage->balancer;
-
+
$schema->storage->read_handler($balanced_handler);
}
}
$self->master->cursor_class;
}
-
+
=head1 GOTCHAS
Due to the fact that replicants can lag behind a master, you must take care to
my $new_schema = $schema->clone;
$new_schema->set_reliable_storage;
-
+
## $new_schema will use only the Master storage for all reads/writes while
## the $schema object will use replicated storage.
projects / dbsrgits/DBIx-Class.git / blobdiff