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 requieres 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 occurence 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 occurence.
- 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 occurence 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 possiblities 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 occuring (as in add_callback)
filehandle => the related file descriptor. Notice that the
user is in charge of performing the I/O
operation itslef (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 occured 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.