NAME
perfSONAR_PS::Services::MP::Agent::CommandLine - A module that will run a command and return it's output.
DESCRIPTION
Inherited perfSONAR_PS::MP::Agent::Base class that allows a command to be executed. Specific tools should inherit from this class and override parse() in order to be able to format the command line output in a well understood data structure.
SYNOPSIS
# command line to run, variables are indicated with the '%...%' notation
my $command = '/bin/ping -c %count% %destination%';
# options to use, the above keys defined in $command will be
# substituted with the following values
my %options = (
'count' => 10,
'destination' => 'localhost',
);
# create and setup a new Agent
my $agent = perfSONAR_PS::Services::MP::Agent::CommandLine( $command, $options );
$agent->init();
# collect the results (i.e. run the command)
if( $mp->collectMeasurements() == 0 )
{
# get the raw datastructure for the measurement
print "Results:\n" . $self->results() . "\n";
}
# opps! something went wrong! :(
else {
print STDERR "Command: '" . $self->commandString() . "' failed with result '" . $self->results() . "': " . $agent->error() . "\n";
}
new( $command, $options, $namespace)
Creates a new agent class
$command = complete path to command line tool to run, eg /bin/ping
$options = special parsed string of arguments for the tool; this string will have variables replaced at run time
$namespace = perfSONAR_PS::XML::Namespace object
command( $string )
accessor/mutator function for the generic command to run (normally set in the constructor). This command should have variable fields marked up between '%'s. For example for a ping we would have something like:
'/bin/ping -c %count% %destination%';
This would then have the values to these variables substituted in at runtime.
commandString( $string )
accessor/mutator function for the actual command line to run; this would be the run time command after $self->command() has had the relevant variables substituted.
options( \%hash )
accessor/mutator function for the variable=value set to substitute the $self->command() line with. ie for the ping example with command(), we would have:
$self->command( '/bin/ping -c %count% %destination%' );
$self->options( {
'count' => 10,
'destination' => 'localhost',
};
which would result in /bin/ping -c 10 localhost
init( )
does anything necessary before running the collect() such as modifying the options etc. Check to see that the command exists
collectMeasurements( )
Runs the command with the options specified in constructor. The return of this method should be
-1 = something failed
0 = command ran okay
on success, this method should call the parse() method to determine the relevant performance output from the tool.
parse( )
Given the output of the command as a ref to an array of strings (\@array), and the original command line that generated those strings ($commandLine) at time $time (epoch secs),
do something with that output and store in into $self->{RESULTS}.
Return:
-1 = could not parse output
0 = everything parsed okay
The data structure is completely arbitary, but should be understood by the inherited class.