Author: stas
Date: Sat Feb 19 09:12:28 2005
New Revision: 154424
URL: http://svn.apache.org/viewcvs?view=rev&rev=154424
Log:
- document that spawn_proc_prog now can be called in a scalar context
- add a code example showing how to run a detached process
Modified:
perl/modperl/docs/trunk/src/docs/2.0/api/Apache/SubProcess.pod
Modified: perl/modperl/docs/trunk/src/docs/2.0/api/Apache/SubProcess.pod
URL:
http://svn.apache.org/viewcvs/perl/modperl/docs/trunk/src/docs/2.0/api/Apache/SubProcess.pod?view=diff&r1=154423&r2=154424
==============================================================================
--- perl/modperl/docs/trunk/src/docs/2.0/api/Apache/SubProcess.pod (original)
+++ perl/modperl/docs/trunk/src/docs/2.0/api/Apache/SubProcess.pod Sat Feb 19
09:12:28 2005
@@ -41,6 +41,11 @@
}
return defined $data ? $data : '';
}
+
+ # pass @ARGV but don't ask for any communication channels
+ $command = "/tmp/argv.pl";
+ @argv = qw(foo bar);
+ $r->spawn_proc_prog($command, [EMAIL PROTECTED]);
@@ -66,6 +71,8 @@
Spawn a sub-process and return STD communication pipes:
+ $r->spawn_proc_prog($command);
+ $r->spawn_proc_prog($command, [EMAIL
PROTECTED]);
$out_fh = $r->spawn_proc_prog($command);
$out_fh = $r->spawn_proc_prog($command, [EMAIL
PROTECTED]);
($in_fh, $out_fh, $err_fh) = $r->spawn_proc_prog($command);
@@ -87,8 +94,11 @@
=item ret: ...
-In SCALAR context returns the output filehandle of the spawned
-process.
+In VOID context returns no filehandles (all std streams to the spawned
+process are closed).
+
+In SCALAR context returns the output filehandle of the spawned process
+(the in and err std streams to the spawned process are closed).
In LIST context returns the input, outpur and error filehandles of the
spawned process.
@@ -137,6 +147,41 @@
memory. Most likely the best solution here is to offload the job to
PPerl or some other daemon, with the only added complexity of
communication.
+
+To spawn a completely independent process, which will be able to run
+after Apache has been shutdown and which won't prevent Apache from
+restarting (releasing the ports Apache is listening to) call
+spawn_proc_prog() in a void context and make the script detach and
+close/reopen its communication streams. For example, spawn a process
+as:
+
+ use Apache::SubProcess ();
+ $r->spawn_proc_prog ('/path/to/detach_script.pl', $args);
+
+and the F</path/to/detach_script.pl> contents are:
+
+ # file:detach_script.pl
+ #!/usr/bin/perl -w
+ use strict;
+ use warnings;
+
+ use POSIX 'setsid';
+
+ open STDIN, '/dev/null' or die "Can't read /dev/null: $!";
+ open STDOUT, '+>>', '/path/to/apache/error_log'
+ or die "Can't write to /dev/null: $!";
+ open STDERR, '>&STDOUT' or die "Can't dup stdout: $!";
+ setsid or die "Can't start a new session: $!";
+
+ # run your code here or call exec to another program
+
+reopening (or closing) the STD streams and called C<setsid()> makes
+sure that the process is now fully detached from Apache and has a life
+of its own.
+
+
+
+
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