Provided by: libtaktuk-perl_3.7.7-1_all 
NAME
TakTuk::Pilot - Perl module that ease "taktuk(1)" execution and related I/O management
SYNOPSIS
use TakTuk::Pilot;
our @line_counter;
sub output_callback(%) {
my %parameters = @_;
my $field = $parameters{fields};
my $rank = $field->{rank};
my $argument = $parameters{argument};
$argument->[$rank] = 1 unless defined($argument->[$rank]);
print "$field->{host}-$rank : ".
"$argument->[$rank] > $field->{line}\n";
$argument->[$rank]++;
}
sub user_input_callback(%) {
my %parameters = @_;
my $taktuk = $parameters{taktuk};
my $descriptor = $parameters{filehandle};
my $buffer;
my $result = sysread($descriptor, $buffer, 1024);
warn "Read error $!" if not defined($result);
# basic parsing, we assume input is buffered on a line basis
chomp($buffer);
if (length($buffer)) {
print "Executing $buffer\n";
$taktuk->send_command("broadcast exec [ $buffer ]");
}
if (not $result) {
print "Terminating\n";
$taktuk->remove_descriptor(type=>'read',
filehandle=>$descriptor);
$taktuk->send_termination();
}
}
die "This script requires as arguments hostnames to contact\n"
unless scalar(@ARGV);
my $taktuk = TakTuk::Pilot->new();
$taktuk->add_callback(callback=>\&output_callback, stream=>'output',
argument=>\@line_counter,
fields=>['host', 'rank', 'line']);
$taktuk->add_descriptor(type=>'read', filehandle=>\*STDIN,
callback=>\&user_input_callback);
$taktuk->run(command=>"taktuk -s -m ".join(" -m ", @ARGV));
DESCRIPTION
The TakTuk::Pilot Perl module ease the use of TakTuk from within a Perl program (see
taktuk(1) for a detailed description of TakTuk). It transparently manages I/O exchanges as
well as TakTuk data demultiplexing and decoding.
CONSTRUCTOR
new()
Creates a new TakTuk object on which the following method can be called.
METHODS
add_callback(%)
Adds a callback function associated to some TakTuk output stream to the calling TakTuk
object. This callback function will be called by TakTuk::Pilot for each batch of
output data incoming from the related stream. The hash passed as argument to this
function call may contain the following fields:
callback => reference to the callback fonction (mandatory)
stream => stream related to this callback, might be
'default' (mandatory)
fields => reference to an array of fields names relevant
to the user
argument => scalar that should be passed to each callback
function call
The callback function should accept a hash as argument. This hash will be populated
with the following fields :
taktuk => reference to the taktuk object calling this
callback
argument => scalar given at callback addition or undef
stream => stream on which output data came
fields => reference to a hash containing a
fieldname/value pair for each field requested
upon callback addition
send_command($)
Sends to the calling TakTuk object the command passed as argument. Note that if the
TakTuk object is not running, this command will be buffered and executed upon run.
send_termination()
Sends to the calling TakTuk object a termination command. As for "send_command", if
the TakTuk object is not running, this command will be issued upon run.
run(%)
Runs TakTuk, executing pending commands and waiting for TakTuk output. Note that this
function is blocking: it waits for TakTuk outputs, possibly calls related callback
functions and returns when TakTuk terminates. Thus, all TakTuk commands should be
given either before calling "run" or within a callback function.
This commands takes a hash as argument that may contain the following fields:
command => TakTuk command line to be executed
timeout => optional timeout on the wait for TakTuk output
Upon occurrence of the timeout (if one has been given), "run" will returns an "ETMOUT"
error code. Note the in this case TakTuk execution will not be terminated and should
be resumed at some point by calling "continue".
continue()
Resumes a TakTuk execution interrupted by timeout occurrence.
add_descriptor(%)
Because the call to "run" is blocking, waiting for TakTuk output, it might be
interesting to let the "TakTuk::Pilot" module monitor I/O occurrence related to other
file descriptors. This is the intent of "add_descriptor". This function takes a hash
as parameter in which the following fields might be defined:
type => 'read', 'write' or 'exception', this is the
type of I/O possibilities that should be
monitored on the descriptor, as in select
system call (mandatory).
filehandle => file descriptor to monitor (mandatory).
callback => reference to the callback function that
should be called when I/O is possible on the
file descriptor.
argument => optional scalar value that will be passed
with each call to the callback function
The callback function should also accept a hash as an argument in which the following
fields will be defined:
taktuk => reference to the TakTuk object from which
the function was called.
type => type of I/O occurring (as in add_callback)
filehandle => the related file descriptor. Notice that the
user is in charge of performing the I/O
operation itself (sysread or syswrite).
Notice also that, because of the use of a
select in TakTuk::Pilot, the use of buffered
I/O on this descriptor is strongly discouraged
argument => the argument that was given to add_descriptor
remove_descriptor(%)
Function that should be called to remove from the TakTuk object a descriptor
previously added with "add_descriptor". It takes a hash as argument in which the
following fields may be defined:
type => type of I/O (see add_descriptor)
filehandle => file descriptor to remove
quiet() / verbose()
Change verbosity of "TakTuk::Pilot" on STDOUT (default is quiet). Should not be called
when TakTuk is running.
create_session()
Call "setsid" in the TakTuk process created by "run". The main purpose of this call is
to prevent TakTuk from receiving signals sent to the process group to which the pilot
belong. Should not be called when TakTuk is running.
pid()
Returns the pid of the process spawned to run TakTuk. Should only be called when
TakTuk is running.
error_msg($)
Static function. Returns a character string that corresponds to the error code given
as argument. The error code should be one of the values returned by other
"TakTuk::Pilot" functions ("add_callback", "send_command", "send_termination", ...).
ERRORS
When an error occur in one of these functions, it returns a non nul numeric error code.
This code can take one of the following values:
TakTuk::Pilot::EARGCM
Field 'command' is missing in a call to "run".
TakTuk::Pilot::EARGCB
Field 'callback' is missing in a call to "add_callback" or "add_descriptor".
TakTuk::Pilot::EARGFH
Field 'filehandle' is missing in a call to "add_descriptor" or "remove_descriptor".
TakTuk::Pilot::EARGTP
Field 'type' is missing in a call to "add_descriptor" or "remove_descriptor".
TakTuk::Pilot::ETMOUT
A timeout occurred in a call to "run".
TakTuk::Pilot::ETKTRN
TakTuk is alredy running but "run", "verbose" or "quiet" has been called.
TakTuk::Pilot::ETKTNR
TakTuk is not running but "continue" has been called.
TakTuk::Pilot::ESPIPE
A call to "pipe" failed in "TakTuk::Pilot" (the error should be in $!).
TakTuk::Pilot::ESFORK
A call to "fork" failed in "TakTuk::Pilot" (the error should be in $!).
TakTuk::Pilot::ESCLOS
A call to "close" failed in "TakTuk::Pilot" (the error should be in $!).
TakTuk::Pilot::ESELEC
A call to "select" failed in "TakTuk::Pilot" (the error should be in $!).
TakTuk::Pilot::ETPBUG
Internal bug detected in "TakTuk::Pilot".
SEE ALSO
tatkuk(1), taktukcomm(3), TakTuk(3)
AUTHOR
The original concept of TakTuk has been proposed by Cyrille Martin in his PhD thesis.
People involved in this work include Jacques Briat, Olivier Richard, Thierry Gautier and
Guillaume Huard.
The author of the version 3 (perl version) and current maintainer of the package is
Guillaume Huard.
COPYRIGHT
The "TakTuk" communication interface library is provided under the terms of the GNU
General Public License version 2 or later.