Re: Help -- how to fork an Apache process in mod_perl safely? Not Apache2:Subprocess...
William T wrote:
There are all kinds of problems that you'll encounter and have to solve
if you fork. I found it's better to call at(1) to start another
seperate process immediatly. If you need to pass data JSON worked
really well for me.
Thanks, that's what I ended up doing. First I ended up having to move
the processing into an external script call anyway, and then I tried
Apache2::SubProcess, and it ended up working, but my script was randomly
receiving TERM signals... it's handleable of course, but I decided to go
with the 'at' technique, it's safer that way, I suppose.
On Aug 25, 2009 5:12 AM, Victor Danilchenko vic...@askonline.net
mailto:vic...@askonline.net wrote:
Hi all,
I need to be able to fork an Apache process in daemon form, to
do some housekeeping which might potentially take a few seconds.
However, when I do that, I start getting SQL errors (of the
connection lost type) in the browser. I do the fairly standard
cleanup to daemonize the child process, but of course it needs to
retain the SQL socket open. Here is my forking code:
sub modperl_kamikaze_fork () {
# You will have to do CORE::exit(0) at the end of the execution.
$SIG{CHLD} = 'IGNORE';
get_m-flush_buffer;
defined (my $kid = fork) or die Cannot fork: $!\n;
return $kid if $kid;
my $r = get_r;
close STDIN; open STDIN, '/dev/null'
or die Can't read /dev/null: $!;
close STDOUT; open STDOUT, '/dev/null'
or die Can't write to /dev/null: $!;
close STDERR; open STDERR, '/tmp/form.log'
or die Cannot open /tmp/fork.log\n;
setsid
or die Can't start a new session: $!;
my $oldfh = select STDERR;
local $| = 1;
select $oldfh;
warn Child (PID $$) spawned.\n;
$r-child_terminate;
}
The Apache2:Subprocess doesn't help me, because I need not to
spawn an external process, but to finish processing in mod_perl
context -- just without bugging the user with it.
Any ideas on how to either fork better, or how to solve this
without forking (e.g. is there a way to 'append' a function call to
the request after the rest of the request is completed)?
Many thanks in advance.
--
Victor Danilchenko
Senior Software Engineer, AskOnline.net
vic...@askonline.net mailto:vic...@askonline.net - 617-273-0119
--
Victor Danilchenko
Senior Software Engineer, AskOnline.net
vic...@askonline.net - 617-273-0119
Help -- how to fork an Apache process in mod_perl safely? Not Apache2:Subprocess...
Hi all,
I need to be able to fork an Apache process in daemon form, to do some
housekeeping which might potentially take a few seconds. However, when I
do that, I start getting SQL errors (of the connection lost type) in
the browser. I do the fairly standard cleanup to daemonize the child
process, but of course it needs to retain the SQL socket open. Here is
my forking code:
sub modperl_kamikaze_fork () {
# You will have to do CORE::exit(0) at the end of the execution.
$SIG{CHLD} = 'IGNORE';
get_m-flush_buffer;
defined (my $kid = fork) or die Cannot fork: $!\n;
return $kid if $kid;
my $r = get_r;
close STDIN; open STDIN, '/dev/null'
or die Can't read /dev/null: $!;
close STDOUT; open STDOUT, '/dev/null'
or die Can't write to /dev/null: $!;
close STDERR; open STDERR, '/tmp/form.log'
or die Cannot open /tmp/fork.log\n;
setsid
or die Can't start a new session: $!;
my $oldfh = select STDERR;
local $| = 1;
select $oldfh;
warn Child (PID $$) spawned.\n;
$r-child_terminate;
}
The Apache2:Subprocess doesn't help me, because I need not to spawn an
external process, but to finish processing in mod_perl context -- just
without bugging the user with it.
Any ideas on how to either fork better, or how to solve this without
forking (e.g. is there a way to 'append' a function call to the request
after the rest of the request is completed)?
Many thanks in advance.
--
Victor Danilchenko
Senior Software Engineer, AskOnline.net
vic...@askonline.net - 617-273-0119
Re: Help -- how to fork an Apache process in mod_perl safely? Not Apache2:Subprocess...
On Tue, Aug 25, 2009 at 8:11 AM, Victor Danilchenkovic...@askonline.net wrote: I need to be able to fork an Apache process in daemon form, to do some housekeeping which might potentially take a few seconds. However, when I do that, I start getting SQL errors (of the connection lost type) in the browser. I do the fairly standard cleanup to daemonize the child process, but of course it needs to retain the SQL socket open. You can't fork and keep using a database connection. You have to open a new connection in the forked process. The Apache2:Subprocess doesn't help me, because I need not to spawn an external process, but to finish processing in mod_perl context -- just without bugging the user with it. In that case, just use a cleanup handler instead. - Perrin
Re: Help -- how to fork an Apache process in mod_perl safely? Not Apache2:Subprocess...
my solution is here:
sub fork_temporary_child {
my $result = fork();
unless( $result ) {
# Do not use SQL in child
dbh-{InactiveDestroy} = 1;
disconnect_dbh;
}
return $result;
}
On Tue, Aug 25, 2009 at 7:11 AM, Victor Danilchenko vic...@askonline.netwrote:
Hi all,
I need to be able to fork an Apache process in daemon form, to do
some housekeeping which might potentially take a few seconds. However, when
I do that, I start getting SQL errors (of the connection lost type) in the
browser. I do the fairly standard cleanup to daemonize the child process,
but of course it needs to retain the SQL socket open. Here is my forking
code:
sub modperl_kamikaze_fork () {
# You will have to do CORE::exit(0) at the end of the execution.
$SIG{CHLD} = 'IGNORE';
get_m-flush_buffer;
defined (my $kid = fork) or die Cannot fork: $!\n;
return $kid if $kid;
my $r = get_r;
close STDIN; open STDIN, '/dev/null'
or die Can't read /dev/null: $!;
close STDOUT; open STDOUT, '/dev/null'
or die Can't write to /dev/null: $!;
close STDERR; open STDERR, '/tmp/form.log'
or die Cannot open /tmp/fork.log\n;
setsid
or die Can't start a new session: $!;
my $oldfh = select STDERR;
local $| = 1;
select $oldfh;
warn Child (PID $$) spawned.\n;
$r-child_terminate;
}
The Apache2:Subprocess doesn't help me, because I need not to spawn
an external process, but to finish processing in mod_perl context -- just
without bugging the user with it.
Any ideas on how to either fork better, or how to solve this without
forking (e.g. is there a way to 'append' a function call to the request
after the rest of the request is completed)?
Many thanks in advance.
--
Victor Danilchenko
Senior Software Engineer, AskOnline.net
vic...@askonline.net - 617-273-0119
Re: Help -- how to fork an Apache process in mod_perl safely? Not Apache2:Subprocess...
There are all kinds of problems that you'll encounter and have to solve if
you fork. I found it's better to call at(1) to start another seperate
process immediatly. If you need to pass data JSON worked really well for
me.
-wjt
On Aug 25, 2009 5:12 AM, Victor Danilchenko vic...@askonline.net wrote:
Hi all,
I need to be able to fork an Apache process in daemon form, to do
some housekeeping which might potentially take a few seconds. However, when
I do that, I start getting SQL errors (of the connection lost type) in the
browser. I do the fairly standard cleanup to daemonize the child process,
but of course it needs to retain the SQL socket open. Here is my forking
code:
sub modperl_kamikaze_fork () {
# You will have to do CORE::exit(0) at the end of the execution.
$SIG{CHLD} = 'IGNORE';
get_m-flush_buffer;
defined (my $kid = fork) or die Cannot fork: $!\n;
return $kid if $kid;
my $r = get_r;
close STDIN; open STDIN, '/dev/null'
or die Can't read /dev/null: $!;
close STDOUT; open STDOUT, '/dev/null'
or die Can't write to /dev/null: $!;
close STDERR; open STDERR, '/tmp/form.log'
or die Cannot open /tmp/fork.log\n;
setsid
or die Can't start a new session: $!;
my $oldfh = select STDERR;
local $| = 1;
select $oldfh;
warn Child (PID $$) spawned.\n;
$r-child_terminate;
}
The Apache2:Subprocess doesn't help me, because I need not to spawn
an external process, but to finish processing in mod_perl context -- just
without bugging the user with it.
Any ideas on how to either fork better, or how to solve this without
forking (e.g. is there a way to 'append' a function call to the request
after the rest of the request is completed)?
Many thanks in advance.
--
Victor Danilchenko
Senior Software Engineer, AskOnline.net
vic...@askonline.net - 617-273-0119
