| Stanley, Andrew S NISO/SMS 2006-06-05, 7:23 pm |
| Classification: UNCLASSIFIED
Caveats: NONE
I've been cutting and pasting POE code for sometime now and though I still
don't understand a lot of it I've been able to use it successfully. I'm now
working on a project in which I need to be able to capture the exit status
of child processes. I'd really like to be able to have each child write to
a shared hash or array but I'm not sure if that's possible.
I have a script that's almost line for line the POE Cookbook "Child Process
3" example. I saw the example in the FAQ for catching a child's exit status
with a signal handler but I'm not sure how to apply this to my code.
Specifically the hash of PIDs to wheels.
$heap->{pid_to_wheel}->{ $new_wheel->PID } = $new_wheel;
$heap->{id_to_wheel}->{ $new_wheel->ID } = $new_wheel;
Here's an example of how I tried to implement it....
POE::Session->create
( inline_states =>
{ _start => \&start_tasks,
next_task => \&start_tasks,
task_result => \&handle_task_result,
task_done => \&handle_task_done,
task_debug => \&handle_task_debug,
task_chld => \&sigchld_handler,
}
);
sub start_tasks {
my $heap = $_[HEAP];
while ( keys( %{ $heap->{task} } ) < MAX_CONCURRENT_TASKS ) {
my $next_task = shift @tasks;
last unless defined $next_task;
print "Starting task for $next_task...\n";
my $task = POE::Wheel::Run->new
( Program => sub { do_stuff($next_task,@hosts) },
StdioFilter => POE::Filter::Line->new(), # Child speaks in
lines.
StderrFilter => POE::Filter::Line->new(), # Child speaks in
lines.
StdoutEvent => "task_result",
StderrEvent => "task_debug",
CloseEvent => "task_done",
ErrorEvent => "task_chld",
);
$heap->{task}->{ $task->ID } = $task;
}
}
sub do_stuff {
my $task = shift;
my @hosts = @_;
# The Crux
foreach $host ( @hosts ) {
$return_status = &main($host);
if ( $return_status == 1 ) {
exit 1;
}
}
}
..........
Other subs
...............
sub sigchld_handler {
my ( $heap, $pid, $child_error ) = @_[ HEAP, ARG1, ARG2 ];
return unless exists $heap->{pid_to_wheel}->{$pid};
my $wheel = delete $heap->{pid_to_wheel}->{$pid};
delete $heap->{id_to_wheel}->{ $wheel->ID };
print(
"child process $pid exited with status ",
( $child_error >> 8 ),
"\n"
);
}
# Run until there are no more devices.
$poe_kernel->run();
Any help would be great.
Classification: UNCLASSIFIED
Caveats: NONE
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