Problems with multi-threaded FastCGI server

Thierry Pierron <t.pierron-E+nNfmQdIM/[email protected]> Tue, 18 Apr 2006 15:20:37 -0400

Newsgroups	gmane.comp.web.fastcgi.devel
Message-ID	<[email protected]>

Hello,

First, I know that this has already been asked on this list, but I 
wonder the lack of answer. The problem is simple : I can't make work 
the multi-threaded example provided with libfcgi. I'm running fastcgi 
with Apache 2.0.54 on Win32 with fcgi sdk that can be found here 
http://www.fastcgi.com/dist/.

As far as I've investigated, I got a timeout in the apache log, saying 
that fastcgi server has not respond for 30 seconds. It seems that 
whenever a thread leave the FCGX_Accept_r() function, the connection is 
broken as soon as another thread enter it : I can see the content of 
the first FCGX_FPrintF, just before the sleep(), and then I got the 
classical apache Internal error message.

If I protect the whole loop by a mutex, it works fine, though it's like 
having mono-threaded application.

I included the threaded.c example slighty modified to work with Win32 
API. I wonder if anyone succeed to make it work as a FastCGI server...


-- 
Thierry Pierron
Polkadots Software Inc.
2501 Dollard
Lasalle, QC
H8N 1S2 Canada

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threaded.c (text/plain, 1.7 KB)

/*
 * threaded.c -- A simple multi-threaded FastCGI application.
 */

#include <process.h>
#include <windows.h>
#include <sys/types.h>
#include "fcgiapp.h"

#define THREAD_COUNT 20

static int counts[THREAD_COUNT];

static CRITICAL_SECTION accept_mutex;
static CRITICAL_SECTION counts_mutex;

static void doit(void *a)
{
    int rc, i, thread_id = (int)a;
    FCGX_Request request;
    char *server_name;

    FCGX_InitRequest(&request, 0, 0);

    for (;;)
    {
        /* Some platforms require accept() serialization, some don't.. */
        EnterCriticalSection(&accept_mutex);
        rc = FCGX_Accept_r(&request);
        LeaveCriticalSection(&accept_mutex);

        if (rc < 0)
            break;

        server_name = FCGX_GetParam("SERVER_NAME", request.envp);

        FCGX_FPrintF(request.out,
            "Content-type: text/html\r\n"
            "\r\n"
            "<title>FastCGI Hello! (multi-threaded C, fcgiapp library)</title>"
            "<h1>FastCGI Hello! (multi-threaded C, fcgiapp library)</h1>"
            "Thread %d, Process xyz<p>"
            "Request counts for %d threads running on host <i>%s</i><p><code>",
            thread_id, THREAD_COUNT, server_name ? server_name : "?");

        FCGX_FFlush(request.out);

        Sleep(2000);

        EnterCriticalSection(&counts_mutex);
        ++counts[thread_id];
        for (i = 0; i < THREAD_COUNT; i++)
            FCGX_FPrintF(request.out, "%5d " , counts[i]);
        LeaveCriticalSection(&counts_mutex);

        FCGX_Finish_r(&request);
    }
}

int main(void)
{
    int i;

    FCGX_Init();

    InitializeCriticalSection(&accept_mutex);
    InitializeCriticalSection(&counts_mutex);

    for (i = 1; i < THREAD_COUNT; i++)
        _beginthread(doit, 0, (void*)i);

    doit(0);

    return 0;
}