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package Cassandra::Client::Policy::Throttle::Adaptive;
our $AUTHORITY = 'cpan:TVDW';
$Cassandra::Client::Policy::Throttle::Adaptive::VERSION = '0.21';
use parent 'Cassandra::Client::Policy::Throttle::Default';
use 5.010;
use strict;
use warnings;
use Time::HiRes qw/CLOCK_MONOTONIC/;
use Ref::Util qw/is_blessed_ref/;
use Cassandra::Client::Error::ClientThrottlingError;
sub new {
my ($class, %args)= @_;
return bless {
ratio => $args{ratio} || 2,
time => $args{time} || 120,
window => [],
window_success => 0,
window_total => 0,
}, $class;
}
sub _process_window {
my ($self)= @_;
my $now= Time::HiRes::clock_gettime(CLOCK_MONOTONIC);
while (@{$self->{window}} && $self->{window}[0][0] < $now) {
my $entry= shift @{$self->{window}};
$self->{window_total}--;
$self->{window_success}-- if $entry->[1];
}
return;
}
sub should_fail {
my ($self)= @_;
$self->_process_window;
my $fail= ( rand() < (($self->{window_total} - ($self->{ratio} * $self->{window_success})) / ($self->{window_total} + 1)) );
return unless $fail;
$self->count(undef, 1);
return Cassandra::Client::Error::ClientThrottlingError->new;
}
sub count {
my ($self, $error, $force_error)= @_;
return if is_blessed_ref($error) && $error->isa('Cassandra::Client::Error::ClientThrottlingError');
$self->{window_total}++;
my $success= !(is_blessed_ref($error) && $error->is_timeout) && !$force_error;
push @{$self->{window}}, [ Time::HiRes::clock_gettime(CLOCK_MONOTONIC)+$self->{time}, $success ];
$self->{window_success}++ if $success;
return;
}
1;
__END__
=pod
=head1 NAME
Cassandra::Client::Policy::Throttle::Adaptive
=head1 VERSION
version 0.21
=head1 AUTHOR
Tom van der Woerdt <tvdw@cpan.org>
=head1 COPYRIGHT AND LICENSE
This software is copyright (c) 2023 by Tom van der Woerdt.
This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.
=cut
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