Provided by: libtaktuk-perl_3.7.3-3ubuntu1_amd64 bug

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.

       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.