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lib/ApacheLog/Compressor.pm  view on Meta::CPAN

package ApacheLog::Compressor;
# ABSTRACT: Convert Apache/CLF data to binary format
use strict;
use warnings;

use Socket qw(inet_aton inet_ntoa);
use Date::Parse qw(str2time);
use List::Util qw(min);
use URI;
use URI::Escape qw(uri_unescape);
use DateTime;
use Encode qw(encode_utf8 decode_utf8 FB_DEFAULT is_utf8 FB_CROAK);
use POSIX qw{strftime};

our $VERSION = '0.005';

=head1 NAME

ApacheLog::Compressor - convert Apache / CLF log files into a binary format for transfer

=head1 VERSION

version 0.005

=head1 SYNOPSIS

 use ApacheLog::Compressor;
 use Sys::Hostname qw(hostname);

 # Write all data to bzip2-compressed output file
 open my $out_fh, '>', 'compressed.log.bz2' or die "Failed to create output file: $!";
 binmode $out_fh;
 my $zip = IO::Compress::Bzip2->new($out_fh, BlockSize100K => 9);

 # Provide a callback to send data through to the file
 my $alc = ApacheLog::Compressor->new(
	on_write	=> sub {
		my ($self, $pkt) = @_;
		$zip->write($pkt);
	}
 );

 # Input file - normally use whichever one's just been closed + rotated
 open my $fh, '<', '/var/log/apache2/access.log.1' or die "Failed to open log: $!";

 # Initial packet to identify which server this came from
 $alc->send_packet('server',
 	hostname	=> hostname(),
 );

 # Read and compress all the lines in the files
 while(my $line = <$fh>) {
	 $alc->compress($line);
 }
 close $fh or die $!;
 $zip->close;

 # Dump the stats in case anyone finds them useful
 $alc->stats;

=head1 DESCRIPTION

Converts data from standard Apache log format into a binary stream which is typically 20% - 60% the size of the original file.
Intended for cases where log data needs transferring from multiple high-volume servers for analysis (potentially in realtime
via tail -f).

The log format is a simple dictionary replacement algorithm: each field that cannot be represented in a fixed-width datatype
is replaced with an indexed value, allowing the basic log line packet to be fixed size with additional packets containing the
first instance of each variable-width data item.

Example:

lib/ApacheLog/Compressor.pm  view on Meta::CPAN

=head2 default_format

Returns the default format used for parsing log lines.

This is an arrayref containing key => value pairs, see L</FORMAT SPECIFICATION> for
more details.

=cut

sub default_format {
	my $self = shift;
	return [
		type		=> { type => 'C1' },
		vhost		=> { id => 0x03, type => 'n1', regex => qr{([^ ]+)} },
		duration	=> { type => 'N1', regex => qr{(\d+)} },
		ip		=> {
			type => 'N1',
			regex => qr{(\S+)\s+\S+},
			process_in => sub {
				my ($self, $data) = @_;
				$data->{ip} = unpack('N1', inet_aton($data->{ip}));
			},
			process_out => sub {
				my ($self, $data) = @_;
				$data->{ip} = inet_ntoa(pack('N1', $data->{ip}));
			}
		},
		user		=> { id => 0x04, type => 'n1', regex => qr{(\S+)} },
		timestamp	=> {
			id => 0x02,
			regex => qr{\[([^\]]+)\]},
			process_in => sub {
				my ($self, $data) = @_;
				$data->{timestamp} = str2time($data->{timestamp});
			}
		},
		method		=> {
			type => 'C1',
			regex => qr{"([^ ]+)},
			process_in => sub {
				my ($self, $data) = @_;
				$data->{method} = $HTTP_METHOD{$data->{method}};
			},
			process_out => sub {
				my ($self, $data) = @_;
				$data->{method} = $HTTP_METHOD_LIST[$data->{method}];
			}
		},
		url		=> {
			id => 0x07,
			type => 'N1',
			regex => qr{([^ ]+)},
			process_in => sub {
				my ($self, $data) = @_;
				return $data->{url} = '' unless defined $data->{url};

				($data->{url}, $data->{query}) = split /\?/, $data->{url}, 2;
# Dodgy UTF8 handling, currently disabled - no guarantee that URLs are UTF8 anyway
#				if(length $data->{url}) {
				# URI::Escape's uri_unescape but in byte mode so we can check utf8 decoding manually
#					my $txt = $data->{url};
#					$txt = encode_utf8($txt); # turn OFF utf8
#					$txt =~ s/%([0-9A-Fa-f]{2})/pack("C1", hex($1))/ge; # expand
#					$txt = decode_utf8($txt); # turn ON utf8 where applicable
#					$data->{url} = $txt;
#				}
#				if(defined $data->{query} && length $data->{query}) {
				# URI::Escape's uri_unescape but in byte mode so we can check utf8 decoding manually
#					(my $txt = $data->{query}) =~ s/%([0-9A-Fa-f]{2})/pack("C1", hex($1))/eg;
#					$data->{query} = decode_utf8($txt, FB_DEFAULT);
#				}
			}
		},
		query		=> { id => 0x0A, type => 'N1', },
		ver		=> {
			type => 'C1',
			regex => qr{HTTP/(\d+\.\d+)"},
			process_in => sub {
				my ($self, $data) = @_;
				$data->{ver} = ($data->{ver} eq '1.0' ? 0 : 1);
			}, process_out => sub {
				my ($self, $data) = @_;
				$data->{ver} = ($data->{ver} ? '1.1' : '1.0');
			}
		},
		result		=> { type => 'n1', regex => qr{(\d+)} },
		size		=> {
			type => 'N1',
			regex => qr{(\d+|-)},
			process_in => sub {
				my ($self, $data) = @_;
				$data->{size} = ($data->{size} eq '-') ? -1 : $data->{size};
			}, process_out => sub {
				my ($self, $data) = @_;
				$data->{size} = ($data->{size} == 4294967295) ? '-' : $data->{size};
			}
		},
		refer		=> { id => 0x06, type => 'n1', regex => qr{"([^"]*)"} },
		useragent	=> { id => 0x05, type => 'n1', regex => qr{"([^"]*)"} },
	];
}

=head2 update_mapping

Refresh the mapping from format keys and internal definitions.

=cut

sub update_mapping {
	my $self = shift;
	my %fmt = @{ $self->{format} };
	$self->{format_hash} = \%fmt;
	$self->{packet_handler} = {
		0x00 => 'log',
		0x01 => 'server',
		0x80 => 'reset',
		map { $fmt{$_}->{id} => $_ } grep { exists $fmt{$_}->{id} } keys %fmt
	};

# Extract information from format strings so that we know how big the packets are and where the data goes
	my @fmt = @{$self->{format}};
	my $pack_str = '';
	my $log_len = 0;
	my @format_keys;
	my @regex;
	ITEM:
	while(@fmt) {
		my $k = shift(@fmt);
		my $v = shift(@fmt);
		$v = { type => $v } unless ref $v;
		if(exists $v->{regex}) {
			push @regex, $v->{regex};
			push @{$self->{log_regex_keys}}, $k;
		}
		if(exists $v->{process_in}) {
			push @{$self->{log_process}}, $v->{process_in};
		}
		if(exists $v->{process_out}) {
			push @{$self->{log_process_out}}, $v->{process_out};
		}

		my $type = $v->{type};
		next ITEM unless $type;

		push @format_keys, $k;
		$pack_str .= $type;

# Obviously these will need updating if we use any other pack() datatypes
		if($type =~ /^C(\d+)/) {
			$log_len += $1;
		} elsif($type =~ /^n(\d+)/) {
			$log_len += 2 * $1;
		} elsif($type =~ /^N(\d+)/) {
			$log_len += 4 * $1;
		} else {
			die "no idea what $type is";
		}
	}
	my $regex = join(' ', @regex);
	$self->{log_regex} = qr{^$regex};
	$self->{log_format} = $pack_str;
	$self->{log_record_length} = $log_len;
	$self->{format_keys} = \@format_keys;
	return $self;
}

=head2 cached

Returns the index for the given type and value, generating a packet if no previous value was found.

=cut

sub cached {
	my $self = shift;
	my ($type, $v) = @_;
	$v = '' unless defined $v;
	my $id = $self->{entry_cache}->{$type}->{$v};
	unless(defined $id) {
		push @{ $self->{entry_index}->{$type} }, $v;
		++$self->{entry_count}->{$type};
		$id = $self->{entry_cache}->{$type}->{$v} = scalar(@{ $self->{entry_index}->{$type} }) - 1;
		$self->send_packet($type, id => $id, data => encode_utf8($v));
	}
	return $id;
}

=head2 from_cache

Read a value from the cache, for expanding compressed log format entries.

=cut

sub from_cache {
	my $self = shift;
	my ($type, $id) = @_;
	die "ID $id not found for $type\n" unless defined $self->{entry_index}->{$type}->[$id];
	return $self->{entry_index}->{$type}->[$id];
}

=head2 set_key

Set a cache index key to a value when expanding a packet stream.

=cut

sub set_key {
	my $self = shift;
	my $type = shift;
	my %args = @_;
	my $v = decode_utf8($args{data});
	$self->{entry_cache}->{$type}->{$v} = $args{id};
	$self->{entry_index}->{$type}->[$args{id}] = $v;
	$self->{"on_set_$type"}->($self, $args{id}, $v) if $self->{"on_set_$type"};
	$self->{"on_set_key"}->($self, $type, $args{id}, $v) if $self->{on_set_key};
	return $self;
}

=head2 compress

General compression function. Given a line of data, sends packets as required to transmit that information.

=cut

sub compress {
	my $self = shift;
	my $txt = shift;
	my %data;
	@data{@{$self->{log_regex_keys}}} = $txt =~ m!$self->{log_regex}!
		or return $self->invoke_event(bad_data => $txt);
	$data{type} = 0;
	$_->($self, \%data) for @{$self->{log_process}};
	return if exists($self->{filter}) && !$self->{filter}->($self, \%data);

	if(!defined($self->{timestamp}) || $data{timestamp} != $self->{timestamp}) {
		$self->{timestamp} = $data{timestamp};
		$self->send_packet('timestamp', timestamp => $self->{timestamp});
	}

	my @fmt = @{$self->{format}};
	my @data;
	while(@fmt) {
		my $k = shift(@fmt);
		my $v = shift(@fmt);
		if($v->{type}) {
			$data{$k} = $self->cached($k, $data{$k}) if exists $v->{id};
			push @data, $data{$k};
		}
	}
	$self->write_packet(pack($self->{log_format}, @data));

	# Recycle everything after 5m entries
	if($self->{log_packet_count}++ >= 5000000) {
		$self->send_packet('reset');
		$self->{log_packet_count} = 0;
	}
	return $self;
}

=head2 send_packet

Generate and send a packet for the given type.

=cut

sub send_packet {
	my $self = shift;
	my $type = shift;

# Try the specific method for this packet if we have one
	my $method = "packet_$type";