Test2::Harness::Util::IPC - Utilities for IPC management.
This package provides low-level IPC tools for Test2::Harness.
All exports are optional and must be specified at import time.
- $bool = USE_P_GROUPS()
- This is a shortcut for:
use Config qw/%Config/;
$Config{'d_setpgrp'};
- swap_io($from,
$to)
- swap_io($from,
$to, \&die)
- This will close and re-open the file handle designated by
$from so that it redirects to the handle specified
in $to. It preserves the file descriptor in the
process, and throws an exception if it fails to do so.
swap_io(\*STDOUT, $fh);
# STDOUT now points to wherever $fh did, but maintains the file descriptor number '2'.
As long as the file descriptor is greater than 0 it will open
for writing. If the descriptor is 0 it will open for reading, allowing
for a swap of "STDIN" as well.
Extra effort is made to insure errors go to the real
"STDERR", specially when trying to
swap out "STDERR". If you have trouble
with this, or do not trust it, you can provide a custom coderef as a
third argument, this coderef will be used instead of
"die()" to throw exceptions.
Note that the custom die logic when you do not provide your
own bypasses the exception catching mechanism and will exit your
program. If this is not desirable then you should provide a custom die
subref.
- $pid = run_cmd(command => [...], %params)
- This function will run the specified command and return a pid to you. When
possible this will be done via "fork()"
and "exec()". When that is not possible
it uses the "system(1, ...)" trick to
spawn a new process. Some parameters do not work in the second case, and
are silently ignored.
Parameters:
- command => [$command,
sub { ... }, @args]
- command => sub {
return ($command, @args) }
- This parameter is required. This should either be an arrayref of arguments
for "exec()", or a coderef that returns
a list of arguments for "exec()". On
systems without fork/exec the arguments will be passed to
"system(1, $command, @args)" instead.
If the command arrayref has a coderef in it, the coderef will
be run and its return value(s) will be inserted in its place. This
replacement happens post-chroot
- run_in_parent
=> [sub { ... }, sub { ... }]
- An arrayref of callbacks to be run in the parent process immedietly after
the child process is started.
- run_in_child
=> [sub { ... }, sub { ... }]
- An arrayref of callbacks to be run in the child process immedietly after
fork. This parameter is silently ignored on systems without
fork/exec.
- env => { ENVVAR => $VAL,
... }
- A hashref of custom environment variables to set in the child process. In
the fork/exec model this is done post-fork, in the spawn model this is
done via local prior to the spawn.
- no_set_pgrp
=> $bool,
- Normall "setpgrp(0,0)" is called on
systems where it is supported. You can use this parameter to override the
normal behavior. setpgrp() is not called in the spawn model, so
this parameter is silently ignored there.
- chdir =>
'path/to/dir'
- ch_dir =>
'path/to/dir'
- chdir() to the specified directory for the new process. In the
fork/exec model this is done post-fork in the child. In the spawn model
this is done before the spawn, then a second chdir() puts the
parent process back to its original dir after the spawn.
- stdout =>
$handle
- stderr =>
$handle
- stdin => $handle
- Thise can be used to provide custom STDERR, STDOUT, and STDIN. In the
fork/exec model these are swapped into place post-fork in the child. In
the spawn model the swap occurs pre-spawn, then the old handles are
swapped back post-spawn.
The source code repository for Test2-Harness can be found at
http://github.com/Test-More/Test2-Harness/.
Copyright 2020 Chad Granum <exodist7@gmail.com>.
This program is free software; you can redistribute it and/or
modify it under the same terms as Perl itself.
See http://dev.perl.org/licenses/