package DBIx::Class::Storage::DBI::Replicated::Pool;
use Moose;
-use MooseX::AttributeHelpers;
use DBIx::Class::Storage::DBI::Replicated::Replicant;
use List::Util 'sum';
use Scalar::Util 'reftype';
use DBI ();
use Carp::Clan qw/^DBIx::Class/;
use MooseX::Types::Moose qw/Num Int ClassName HashRef/;
+use DBIx::Class::Storage::DBI::Replicated::Types 'DBICStorageDBI';
+use Try::Tiny;
use namespace::clean -except => 'meta';
=head1 DESCRIPTION
In a replicated storage type, there is at least one replicant to handle the
-read only traffic. The Pool class manages this replicant, or list of
+read-only traffic. The Pool class manages this replicant, or list of
replicants, and gives some methods for querying information about their status.
=head1 ATTRIBUTES
This is an integer representing a time since the last time the replicants were
validated. It's nothing fancy, just an integer provided via the perl L<time|perlfunc/time>
-builtin.
+built-in.
=cut
=head2 replicants
A hashref of replicant, with the key being the dsn and the value returning the
-actual replicant storage. For example if the $dsn element is something like:
+actual replicant storage. For example, if the $dsn element is something like:
"dbi:SQLite:dbname=dbfile"
=item delete_replicant ($key)
-removes the replicant under $key from the pool
+Removes the replicant under $key from the pool
=back
has 'replicants' => (
is=>'rw',
- metaclass => 'Collection::Hash',
+ traits => ['Hash'],
isa=>HashRef['Object'],
default=>sub {{}},
- provides => {
- 'set' => 'set_replicant',
- 'get' => 'get_replicant',
- 'empty' => 'has_replicants',
- 'count' => 'num_replicants',
- 'delete' => 'delete_replicant',
- 'values' => 'all_replicant_storages',
+ handles => {
+ 'set_replicant' => 'set',
+ 'get_replicant' => 'get',
+ 'has_replicants' => 'is_empty',
+ 'num_replicants' => 'count',
+ 'delete_replicant' => 'delete',
+ 'all_replicant_storages' => 'values',
},
);
+around has_replicants => sub {
+ my ($orig, $self) = @_;
+ return !$self->$orig;
+};
+
+has next_unknown_replicant_id => (
+ is => 'rw',
+ traits => ['Counter'],
+ isa => Int,
+ default => 1,
+ handles => {
+ 'inc_unknown_replicant_id' => 'inc',
+ },
+);
+
+=head2 master
+
+Reference to the master Storage.
+
+=cut
+
+has master => (is => 'rw', isa => DBICStorageDBI, weak_ref => 1);
+
=head1 METHODS
This class defines the following methods.
my $dsn;
my $replicant = do {
-# yes this is evil, but it only usually happens once
+# yes this is evil, but it only usually happens once (for coderefs)
+# this will fail if the coderef does not actually DBI::connect
no warnings 'redefine';
my $connect = \&DBI::connect;
local *DBI::connect = sub {
$self->connect_replicant($schema, $connect_info);
};
- if (!$dsn && !$connect_coderef) {
- $dsn = $connect_info->[0];
- $dsn = $dsn->{dsn} if (reftype($dsn)||'') eq 'HASH';
- }
- $replicant->dsn($dsn);
+ my $key;
- my ($key) = ($dsn =~ m/^dbi\:.+\:(.+)$/i);
+ if (!$dsn) {
+ if (!$connect_coderef) {
+ $dsn = $connect_info->[0];
+ $dsn = $dsn->{dsn} if (reftype($dsn)||'') eq 'HASH';
+ }
+ else {
+ # all attempts to get the DSN failed
+ $key = "UNKNOWN_" . $self->next_unknown_replicant_id;
+ $self->inc_unknown_replicant_id;
+ }
+ }
+ if ($dsn) {
+ $replicant->dsn($dsn);
+ ($key) = ($dsn =~ m/^dbi\:.+\:(.+)$/i);
+ }
+ $replicant->id($key);
$self->set_replicant($key => $replicant);
+
push @newly_created, $replicant;
}
$replicant->_determine_driver
});
- DBIx::Class::Storage::DBI::Replicated::Replicant->meta->apply($replicant);
+ Moose::Meta::Class->initialize(ref $replicant);
+
+ DBIx::Class::Storage::DBI::Replicated::Replicant->meta->apply($replicant);
+
+ # link back to master
+ $replicant->master($self->master);
+
return $replicant;
}
connect. For the master database this is desirable, but since replicants are
allowed to fail, this behavior is not desirable. This method wraps the call
to ensure_connected in an eval in order to catch any generated errors. That
-way a slave can go completely offline (ie, the box itself can die) without
+way a slave can go completely offline (e.g. the box itself can die) without
bringing down your entire pool of databases.
=cut
sub _safely {
my ($self, $replicant, $name, $code) = @_;
- eval {
- $code->()
- };
- if ($@) {
- $replicant
- ->debugobj
- ->print(
- sprintf( "Exception trying to $name for replicant %s, error is %s",
- $replicant->_dbi_connect_info->[0], $@)
- );
- return;
- }
- return 1;
+ return try {
+ $code->();
+ 1;
+ } catch {
+ $replicant->debugobj->print(sprintf(
+ "Exception trying to $name for replicant %s, error is %s",
+ $replicant->_dbi_connect_info->[0], $_)
+ );
+ undef;
+ };
}
=head2 connected_replicants
defined by L</maximum_lag>. Replicants that fail any of these tests are set to
inactive, and thus removed from the replication pool.
-This tests L<all_replicants>, since a replicant that has been previous marked
-as inactive can be reactived should it start to pass the validation tests again.
+This tests L</all_replicants>, since a replicant that has been previous marked
+as inactive can be reactivated should it start to pass the validation tests again.
See L<DBIx::Class::Storage::DBI> for more about checking if a replicating
connection is not following a master or is lagging.