mrtglib(1)
NAME
MRTG_lib.pm - Library for MRTG and support scripts
SYNOPSIS
use MRTG_lib;
my ($configfile, @target_names, %globalcfg, %targetcfg);
readcfg($configfile, \@target_names, \%globalcfg, \%targetcfg);
my (@parsed_targets);
cfgcheck(\@target_names, \%globalcfg, \%targetcfg, \@parsed_targets);
DESCRIPTION
MRTG_lib is part of MRTG, the Multi Router Traffic Grapher. It was
separated from MRTG to allow other programs to easily use the same
config files. The main part of MRTG_lib is the config file parser but
some other funcions are there too.
$MRTG_lib::OS
Type of OS: WIN, UNIX, VMS
$MRTG_lib::SL
Slash in the current OS.
$MRTG_lib::PS
Path separator in PATH variable
"readcfg"
"readcfg($file, \@targets, \%globalcfg, \%targetcfg [, $prefix,
\%extrules])"
Reads a config file, parses it and fills some arrays and hashes.
The mandatory arguments are: the name of the config file, a ref to
an array which will be filled with a list of the target names, a
hashref for the global configuration, a hashref for the target
configuration.
The configuration file syntax is:
globaloption: value
targetoption[targetname]: value
aprefix*extglobal: value
aprefix*exttarget[target2]: value
E.g.
workdir: /var/stat/mrtg
target[router1]: 2:public@router1.local.net
14all*columns: 2
The global config hash has the structure
$globalcfg{configoption} = 'value'
The target config hash has the structure
$targetcfg{configoption}{targetname} = 'value'
See mrtg-reference for more information about the MRTG
configuration syntax.
"readcfg" can take two additional arguments to extend the config
file syntax. This allows programs to put their configuration into
the mrtg config file. The fifth argument is the prefix of the
extension, the sixth argument is a hash with the checkrules for
these extension settings. E.g. if the prefix is "14all" "readcfg"
will check config lines that begin with "14all*", i.e. all lines
like
14all*columns: 2
14all*graphsize[target3]: 500 200
against the rules in %extrules. The format of this hash is:
$extrules{option} = [sub{$_[0] =~ m/^\d+$/}, sub{"Error message for $_[0]"}]
i.e.
$extrules{option}[0] -> a test expression
$extrules{option}[1] -> error message if test fails
The first part of the array is a perl expression to test the value
of the option. The test can access this value in the variable
"$arg". The second part of the array is an error message to display
when the test fails. The failed value can be integrated by using
the variable "$arg".
Config settings with an different prefix than the one given in the
"readcfg" call are not checked but inserted into %globalcfg and
%targetcfg. Prefixed settings keep their prefix in the config
hashes:
$targetcfg{'14all*graphsize'}{'target3'} = '500 200'
"cfgcheck"
"cfgcheck(\@target_names, \%globalcfg, \%targetcfg,
\@parsed_targets)"
Checks the configuration read by "readcfg". Checks the values in
the config for syntactical and/or semantical errors. Sets defaults
for some options. Parses the "target[...]" options and filles the
array @parsed_targets ready for mrtg functions.
The first three arguments are the same as for "readcfg". The fourth
argument is an arrayref which will be filled with the parsed target
defs.
"cfgcheck" converts the values of target settings options, e.g.
options[router1]: bits, growright
to a hash:
$targetcfg{'option'}{'bits'}{'router1'} = 1
$targetcfg{'option'}{'growright'}{'router1'} = 1
This is not done by "readcfg" so if you don't use "cfgcheck" you
have to check the scalar variable $targetcfg{'option'}{'router1'}
(MRTG allows options to be separated by space or ',').
"ensureSL"
"ensureSL(\$pathname)"
Checks that the pathname does not contain double path separators
and ends with a path separator. It uses $MRTG_lib::SL as path
separator which will be / or \ depending on the OS.
"log2rrd"
"log2rrd ($router,\%globalcfg,\%targetcfg)"
Convert log file to rrd format. Needs rrdtool.
"datestr"
"datestr(time)"
Returns the time given in the argument as a nicely formated date
string. The argument has to be in UNIX time format (seconds since
1970-1-1).
"timestamp"
"timestamp()"
Return a string representing the current time.
"setup_loghandlers"
"setup_loghandlers(filename)"
Install signalhandlers for __DIE__ and __WARN__ making the errors
go the the specified destination. If filename is 'eventlog' mrtg
will log to the windows event logger.
"expistr"
"expistr(time)"
Returns the time given in the argument formatted suitable for HTTP
Expire-Headers.
"create_pid"
"create_pid()"
Creates a pid file for the mrtg daemon
"demonize_me"
"demonize_me()"
Puts the running program into background, detaching it from the
terminal.
"populatecache"
"populatecache(\%confcache, $host, $reread, $snmpoptshash)"
Reads the SNMP variables ifDescr, ipAdEntIfIndex, ifPhysAddress,
ifName from the host and stores the values in %confcache as
follows:
$confcache{$host}{'Descr'}{ifDescr}{oid} = (ifDescr or 'Dup')
$confcache{$host}{'IP'}{ipAdEntIfIndex}{oid} = (ipAdEntIfIndex or 'Dup')
$confcache{$host}{'Eth'}{ifPhysAddress}{oid} = (ifPhysAddress or 'Dup')
$confcache{$host}{'Name'}{ifName}{oid} = (ifName or 'Dup')
$confcache{$host}{'Type'}{ifType}{oid} = (ifType or 'Dup')
The value (at the right side of =) is 'Dup' if a value was
retrieved muliple times, the retrieved value else.
"readconfcache"
"my $confcache = readconfcache($file)"
Preload the confcache from a file.
"readfromconfcache"
"writeconfcache($confcache,$file)"
Store the current confcache into a file.
"writeconfcache"
"writeconfcache($confcache,$file)"
Store the current confcache into a file.
"storeincache"
"storeincache($confcache,$host,$method,$key,$value)"
"readfromcache"
"readfromcache($confcache,$host,$method,$key)"
"clearfromcache"
"clearfromcache($confcache,$host)"
"debug"
"debug($type, $message)"
Prints the message on STDERR if debugging is enabled for type type.
A debug type is enabled if type is in array @main::DEBUG.
AUTHORS
Rainer Bawidamann <Rainer.Bawidamann@rz.uni-ulm.de> (This Manpage)
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