Current File : //proc/self/root/usr/share/perl5/Munin/Node/SpoolReader.pm
package Munin::Node::SpoolReader;
# $Id$
use strict;
use warnings;
use Carp;
use IO::File;
use Fcntl qw(:DEFAULT :flock);
use Munin::Common::Defaults;
use Munin::Common::SyncDictFile;
use Munin::Node::Logger;
use Munin::Node::Config;
my $config = Munin::Node::Config->instance;
sub new
{
my ($class, %args) = @_;
$args{spooldir} or croak "no spooldir provided";
opendir $args{spooldirhandle}, $args{spooldir}
or croak "Could not open spooldir '$args{spooldir}': $!";
$args{metadata} = _init_metadata($args{spooldir});
# TODO: paranoia check? except dir doesn't (currently) have to be
# root-owned.
return bless \%args, $class;
}
#prepare tied hash for metadata persisted to $spooldir/SPOOL-META
#should we pull these methods into a base class or create a spool manager class?
sub _init_metadata
{
my $spooldir = shift;
my %metadata;
tie %metadata, 'Munin::Common::SyncDictFile', $spooldir . "/SPOOL-META";
return \%metadata;
}
#retrieve metadata value for key
sub get_metadata
{
my ($self, $key) = @_;
return ${ $self->{metadata} }{$key};
}
#set metadata key:value and persist
sub set_metadata
{
my ($self, $key, $value) = @_;
${ $self->{metadata} }{$key} = $value;
}
# returns all output for all services since $timestamp.
sub fetch
{
my ($self, $timestamp) = @_;
my $return_str = '';
my @plugins = $self->_get_spooled_plugins();
logger("timestamp:$timestamp, plugins:@plugins") if $config->{DEBUG};
foreach my $plugin (@plugins) {
$return_str .= $self->_cat_multigraph_file($plugin, $timestamp);
}
return $return_str;
}
sub list
{
my ($self) = @_;
my @plugins = $self->_get_spooled_plugins();
return join(" ", sort @plugins) . "\n";
}
sub _cat_multigraph_file
{
my ($self, $service, $timestamp, $max_samples_per_service) = @_;
# Default $max_samples_per_service is 5, in order to have a 5x time
# increase in catchup. This enables to not overwhelm the munin-update when
# there is big backlog to handle. Use "0" to send an infinite number of
# samples
$max_samples_per_service = 5 if (! defined $max_samples_per_service);
my $data = "";
rewinddir $self->{spooldirhandle}
or die "Unable to reset the spool directory handle: $!";
my $nb_samples_sent = 0;
foreach my $file (readdir $self->{spooldirhandle}) {
next unless $file =~ m/^munin-daemon\.$service\.(\d+)\.(\d+)$/;
next unless $1+$2 >= $timestamp;
open my $fh, '<', "$self->{spooldir}/$file"
or die "Unable to open spool file: $!";
flock($fh, LOCK_SH);
my $epoch;
# wind through to the start of the first results after $timestamp
while (<$fh>) {
($epoch) = m/^timestamp (\d+)/ or next;
logger("Timestamp: $epoch") if $config->{DEBUG};
last if ($epoch > $timestamp);
}
if (eof $fh) {
logger("Epoch $timestamp not found in spool file for '$service'")
if $config->{DEBUG};
next;
}
# The timestamp isn't part of the multigraph protocol,
# just part of spoolfetch, so we have to filter it out,
# and replace each value line with its current value
while (<$fh>) {
chomp;
if (m/^timestamp (\d+)/) {
# epoch is updated
$epoch = $1;
next;
}
# Prepend the currently active timestamp, if neither a specific (numeric) nor an
# undefined ("N") epoch is included in the value line. The regular expression is
# supposed to match the following types of content:
# foo.value 12.3
# bar.value N:45.7
if (m/^(\w+)\.value\s+(?:N:)?([^:]+)$/) {
$_ = "$1.value $epoch:$2";
}
$data .= $_ . "\n";
}
# We just emitted something
$nb_samples_sent ++;
if ($max_samples_per_service && $nb_samples_sent > $max_samples_per_service) {
logger("Already sent $nb_samples_sent for '$service', ending.") if $config->{DEBUG};
last;
}
}
return $data;
}
sub _get_spooled_plugins
{
my ($self) = @_;
rewinddir $self->{spooldirhandle}
or die "Unable to reset the spool directory handle: $!";
my %seen;
return map { m/^munin-daemon\.(.*)\.\d+\.\d+$/ && ! $seen{$1}++ ? $1 : () }
readdir $self->{spooldirhandle};
}
1;
__END__
=head1 NAME
Munin::Node::SpoolReader - Reading side of the spool functionality
=head1 SYNOPSIS
my $spool = Munin::Node::SpoolReader->new(spooldir => $spooldir);
print $spool->fetch(1234567890);
=head1 METHODS
=over 4
=item B<new($args)>
Constructor. 'spooldir' should be the directory L<Munin::Node::SpoolWriter> is
writing to.
=item B<fetch($timestamp)>
Fetches all the plugin results that have been recorded since C<$timestamp>,
in a form suitable to be sent straight over the wire.
=item B<list()>
Lists all the plugin that have been recorded in the spool, in a form suitable
to be sent straight over the wire.
=back
=cut
# vim: sw=4 : ts=4 : et
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