package MogileFS::ReplicationPolicy;
use strict;
=head1 NAME
MogileFS::ReplicationPolicy - base class for file replication policies
=head1 DESCRIPTION
A MogileFS replication policy class implements policy for how files
should be replicated around.
....
=cut
# parse a policy description string, instantiating object(s) along the way
# given $str can be either a scalar, or a scalarref that's eaten away as it's parsed.
sub new_from_policy_string {
my ($class, $str_a) = @_;
# simple case for normal callers: they give us a scalar, but internally
# we work with it as a scalarref that we eat away while parsing.
my $strref = ref $str_a ? $str_a : \$str_a;
$$strref =~ s/^\s*([\w:]+)// or die "Failed to parse policy string: $$strref";
my ($polclass) = ($1);
$polclass = "MogileFS::ReplicationPolicy::$polclass" unless $polclass =~ /:/;
my $rv = eval "use $polclass; 1";
if ($@ || !$rv) {
die "Failed to load replication policy class $polclass: $@\n";
}
return $polclass->new_from_policy_args($strref);
}
# returns:
# 0: replication sufficient
# undef: no suitable recommendations currently.
# >0: devid to replicate to.
sub replicate_to {
my ($self, %args) = @_;
my $fid = delete $args{fid}; # fid scalar to copy
my $on_devs = delete $args{on_devs}; # arrayref of device objects
my $all_devs = delete $args{all_devs}; # hashref of { devid => MogileFS::Device }
my $failed = delete $args{failed}; # hashref of { devid => 1 } of failed attempts this round
my $min = delete $args{min}; # configured min devcount for this class
warn "Unknown parameters: " . join(", ", sort keys %args) if %args;
die "Missing parameters" unless $on_devs && $all_devs && $failed && $fid;
die "UNIMPLEMENTED 'replicate_to' in " . (ref($self) || $self);
}
1;