Arch::Run(3) run subprocesses and capture output


use Gtk2 -init;
use Arch::Run qw(poll run_async LINES);
my $window = Gtk2::Window->new;
my $label = Gtk2::Label->new;
my $pbar = Gtk2::ProgressBar->new;
my $vbox = Gtk2::VBox->new;
$vbox->add($label); $vbox->add($pbar); $window->add($vbox);
$window->signal_connect(destroy => sub { Gtk2->main_quit; });
$window->set_default_size(200, 48); $window->show_all;
sub set_str { $label->set_text($_[0]); }
my $go = 1; # keep progress bar pulsing
Glib::Timeout->add(100, sub { $pbar->pulse; poll(0); $go; });
command => [ 'du', '-hs', glob('/usr/share/*') ],
mode => LINES,
datacb => sub { chomp(my $str = $_[0]); set_str($str); },
exitcb => sub { $go = 0; set_str("exit code: $_[0]"); },


Arch::Run allows the user to run run subprocesses and capture their output in a single threaded environment without blocking the whole application.

You can use either poll to wait for and handle process output, or use handle_output and handle_exits to integrate Arch::Run with your applications main loop.


The following functions are available: run_with_pipe, run_async, get_output_handle, handle_output, poll, wait, killall, observe, unobserve.
run_with_pipe $command
run_with_pipe $executable $argument ...
Fork and exec a program with STDIN and STDOUT connected to pipes. In scalar context returns the output handle, STDIN will be connected to /dev/null. In list context, returns the output and input handle.

The programs standard error handle (STDERR) is left unchanged.

run_async %args
Run a command asyncronously in the background. Returns the subprocesses pid.

Valid keys for %args are:

command => $command
command => [ $executable $argument ... ]
Program and parameters.
mode => $accum_mode
Control how output data is accumulated and passed to data and finish callbacks.

$accum_mode can be one of

No accumulation. Pass output to data callback as it is received.
Accumulate output in lines. Pass every line separately to data callback.
Accumulate all data. Pass complete command output as one block to data callback.
datacb => $data_callback
Codeblock or subroutine to be called when new output is available. Receives one parameter, the accumulated command output.
exitcb => $exit_callback
Codeblock or subroutine to be called when subprocess exits. Receives a single parameter, the commands exit code. (Or maybe not. We have to handle SIG{CHLD} then. But maybe we have to do so anyway.)
get_output_handle $pid
Returns the STDOUT handle of process $pid. You should never directly read from the returned handle. Use IO::Select or IO::Poll to wait for output and call handle_output to process the output.
handle_output $pid
Handle available output from process $pid.

ATTENTION: Call this method only if there really is output to be read. It will block otherwise.

poll $timeout
Check running subprocesses for available output and run callbacks as appropriate. Wait at most $timeout seconds when no output is available.

Returns the number of processes that had output available.

wait $pid
Wait for subprocess $pid to terminate, repeatedly calling poll. Returns the processes exit status or "undef" if poll has already been called after the processes exit.
killall [$signal]
Send signal $signal (SIGINT if omitted) to all managed subprocesses, and wait until every subprocess to terminate.
observe $observer
Register an observer object that wishes to be notified of running subprocesses. $observer should implement one or more of the following methods, depending on which event it wishes to receive.
->cmd_start $pid $executable $argument ...
Called whenever a new subprocess has been started. Receives the subprocesses PID and the executed command line.
->cmd_output_raw $pid $data
Called whenever a subprocess has generated output. Receives the subprocesses PID and a block of output data.

NOTE: $data is not preprocesses (e.g. split into lines). cmd_output_raw receives data block as if RAW mode was used.

->cmd_exit $pid $exitcode
Called whenever a subprocess exits. Receives the subprocesses PID and exit code.
unobserve $observer
Remove $observer from observer list.