FCGI app reloading on every request

[John Nagle]

I'm converting a web app from CGI to FCGI. The application works fine
under FCGI, but it's being reloaded for every request, which makes FCGI
kind of pointless. I wrote a little FCGI app which prints when the program is
loaded and when it gets a request. And indeed, the program gets reloaded for
each HTTP request. Something is probably misconfigured. But what?

I'm using Apache with "mod_fcgid", configured via Plesk. Plesk
sets up "/etc/httpd/conf.d/fcgid.conf" with:

# added by psa-mod-fcgid-configurator
<IfModule mod_fcgid.c>
IdleTimeout 3600
ProcessLifeTime 7200
MaxProcessCount 64
DefaultMaxClassProcessCount 8
IPCConnectTimeout 30
IPCCommTimeout 45
DefaultInitEnv RAILS_ENV production
</IfModule>

which seems reasonable enough, even though I'm not using
Rails or Ruby.

On the Python side, I'm using Python 2.5 on Linux, with Alan
Saddi's "fcgi.py" module.

Everything seems to work correctly, and there are no errors in the Apache
error log. But performance is terrible because the Python code
is reloaded for each request. I can only get about five transactions
a second through, on an dedicated server, with each transaction
doing a simple MySQL request. All the time is going into program loading;
the database is mostly idle.

John Nagle

[=?ISO-8859-1?Q?=22Martin_v=2E_L=F6wis=22?=]

John Nagle schrieb:

I'm converting a web app from CGI to FCGI. The application works fine
under FCGI, but it's being reloaded for every request, which makes FCGI
kind of pointless. I wrote a little FCGI app which prints when the
program is loaded and when it gets a request. And indeed, the program
gets reloaded for
each HTTP request. Something is probably misconfigured. But what?

The most likely reason is that your FastCGI server voluntarily choses
to exit after one request. Can you share the mainloop of your
application?

Regards,
Martin

[John Nagle]

Martin v. Löwis wrote:

John Nagle schrieb:

> I'm converting a web app from CGI to FCGI. The application works fine
under FCGI, but it's being reloaded for every request, which makes FCGI
kind of pointless. I wrote a little FCGI app which prints when the
program is loaded and when it gets a request. And indeed, the program
gets reloaded for
each HTTP request. Something is probably misconfigured. But what?

The most likely reason is that your FastCGI server voluntarily choses
to exit after one request. Can you share the mainloop of your
application?

Regards,
Martin

It turns out that's not the problem.

What's actually happening is that FCGI isn't running at all.
My .fcgi file is being executed by Apache's CGI handler, and
"fcgi.py" recognizes this, then reads the parameters as if
a CGI program. So it works just like a CGI program: one
load per request. Not sure why Apache is doing that yet.
I'm looking at Apache configuration files now.

The main loop is in "fcgi.py", which calls the
user application as a function. The user app doesn't have the
option of exiting after one request, short of aborting without
returning a result.

John Nagle

[=?ISO-8859-1?Q?Michael_Str=F6der?=]

John Nagle wrote:

>
What's actually happening is that FCGI isn't running at all.
My .fcgi file is being executed by Apache's CGI handler, and
"fcgi.py" recognizes this, then reads the parameters as if
a CGI program. So it works just like a CGI program: one
load per request. Not sure why Apache is doing that yet.
I'm looking at Apache configuration files now.

Are you running mod_fastcgi oder mod_fcgid?

Disclaimer: I don't claim to be an expert in that. My web2ldap source
distribution contains two examples configuration files for each of the
modules above for FastCGI over Unix Domain Socket( see directory
<web2ldap-dir>/etc/httpd/, comments of sample-mod_fcgid.conf
misleading). web2ldap can also be deployed as (multi-threaded)
FastCGI-server.

Ciao, Michael.

[John Nagle]

Michael Ströder wrote:

John Nagle wrote:

> What's actually happening is that FCGI isn't running at all.
My .fcgi file is being executed by Apache's CGI handler, and
"fcgi.py" recognizes this, then reads the parameters as if
a CGI program. So it works just like a CGI program: one
load per request. Not sure why Apache is doing that yet.
I'm looking at Apache configuration files now.

Are you running mod_fastcgi oder mod_fcgid?

I'm using mod_fcgid.

This is running on a dedicated server at APlus.net,
running Red Hat Fedora Core 6, Python 2.5, and managed with Plesk 8.2.
I just turned on fcgid from the Plesk control panel ("Physical hosting
setup page for domain", checked "FastCGI"), and enabled the standard
FCGI configuration, which is actually mod_fcgid.

The Python app is launched from "cgi-bin" with a file ending in
".fcgi". It uses Alan Saddi's "fcgi.py" module to interface with
an FCGI server. Python programs that use "fcgi.py" will also run
as standard CGI programs, for debug purposes. And that's what's
happening. I modified my test Python program to patch
"fcgi.CGIrequest._end" with a version that logged its calls,
and that's being called. This indicates that "fcgi.py" is running
in CGI mode, not FCGI mode. My test program is reloaded for every
HTTP request, as indicated by debug output, so it really is running
in CGI mode, with the expected low performance.

What's wierd is that the ".fcgi" suffix files get executed at all.
I'd expect them to be either ignored or run properly with FCGI.

John Nagle

[Thorsten Kampe]

* John Nagle (Mon, 03 Sep 2007 21:26:01 -0700)

I'm converting a web app from CGI to FCGI. The application works fine
under FCGI, but it's being reloaded for every request, which makes FCGI
kind of pointless. I wrote a little FCGI app which prints when the program is
loaded and when it gets a request. And indeed, the program gets reloaded for
each HTTP request. Something is probably misconfigured. But what?
[...]
On the Python side, I'm using Python 2.5 on Linux, with Alan
Saddi's "fcgi.py" module.

Do you use fcgi.py or flup? Go for flup
"What's the difference between flup's fcgi module and your previous
fcgi.py?

Feature-wise, very little, as I do try to keep both implementations in
sync. The most significant difference is that flup's fcgi module uses
thread pooling, fcgi.py simply starts a new thread for each
connection/request. flup's code is refactored and modularized, to
minimize duplicated code between all 6 servers."

http://trac.saddi.com/flup/wiki/Flup...cebetweenflups
fcgimoduleandyourpreviousfcgi.py

[=?UTF-8?B?Ik1hcnRpbiB2LiBMw7Z3aXMi?=]

Anything executable in the

cgi-bin directory is being launched as a CGI program. A file
named "example.foo", if executable, will launch as a CGI program.
Nothing launches with FCGI.

Perhaps you have a SetHandler declaration somewhere that makes all
files CGI by default? I would advise against Sethandler, and
recommend AddHandler instead.

Regards,
Martin

[=?ISO-8859-1?Q?Michael_Str=F6der?=]

John Nagle wrote:

This is running on a dedicated server at APlus.net,
running Red Hat Fedora Core 6, Python 2.5, and managed with Plesk 8.2.
I just turned on fcgid from the Plesk control panel ("Physical hosting
setup page for domain", checked "FastCGI"), and enabled the standard
FCGI configuration, which is actually mod_fcgid.
[..]
What's wierd is that the ".fcgi" suffix files get executed at all.
I'd expect them to be either ignored or run properly with FCGI.

Then I would ask APlus.net what's really going on there.

Ciao, Michael.