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>
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