svn commit: r1647005 - in /httpd/httpd/trunk: CHANGES docs/manual/mod/mod_proxy_fcgi.xml modules/proxy/mod_proxy_fcgi.c

[co...@apache.org]

Author: covener
Date: Sat Dec 20 15:38:27 2014
New Revision: 1647005

URL: http://svn.apache.org/r1647005
Log:
Allow (a hokey) opt-in to connection reuse for mod_proxy_fcgi + TCP.  

Connection reuse has been disabled since r1032345 at the end of
2011. 

Attempt to reverse the polarity of the connection reuse doc which
has been wrong for a long time.


Modified:
    httpd/httpd/trunk/CHANGES
    httpd/httpd/trunk/docs/manual/mod/mod_proxy_fcgi.xml
    httpd/httpd/trunk/modules/proxy/mod_proxy_fcgi.c

Modified: httpd/httpd/trunk/CHANGES
URL: http://svn.apache.org/viewvc/httpd/httpd/trunk/CHANGES?rev=1647005&r1=1647004&r2=1647005&view=diff
==============================================================================
--- httpd/httpd/trunk/CHANGES [utf-8] (original)
+++ httpd/httpd/trunk/CHANGES [utf-8] Sat Dec 20 15:38:27 2014
@@ -1,6 +1,9 @@
                                                          -*- coding: utf-8 -*-
 Changes with Apache 2.5.0
 
+  *) mod_proxy_fcgi: Enable opt-in to TCP connection reuse by explicitly
+     setting proxy option disablereuse=off. [Eric Covener] PR 57378.
+ 
   *) mod_proxy_fcgi: Remove proxy:balancer:// prefix from SCRIPT_FILENAME
      passed to fastcgi backends. [Eric Covener]
 

Modified: httpd/httpd/trunk/docs/manual/mod/mod_proxy_fcgi.xml
URL: http://svn.apache.org/viewvc/httpd/httpd/trunk/docs/manual/mod/mod_proxy_fcgi.xml?rev=1647005&r1=1647004&r2=1647005&view=diff
==============================================================================
--- httpd/httpd/trunk/docs/manual/mod/mod_proxy_fcgi.xml (original)
+++ httpd/httpd/trunk/docs/manual/mod/mod_proxy_fcgi.xml Sat Dec 20 15:38:27 2014
@@ -68,30 +68,26 @@
       </highlight>
     </example>
 
-    <p>This application should be able to handle multiple concurrent
-    connections.  <module>mod_proxy</module> enables connection reuse by
-    default, so after a request has been completed the connection will be
-    held open by that httpd child process and won't be reused until that
-    httpd process routes another request to the application.  If the
-    FastCGI application is unable to handle enough concurrent connections
-    from httpd, requests can block waiting for the application to close
-    an existing connection.  One way to resolve this is to disable connection
-    reuse on the <directive>ProxyPass</directive> directive, as shown in
-    the following example:</p>
+    <p> <module>mod_proxy_fcgi</module> disables connection reuse by
+    default, so after a request has been completed the connection will NOT be
+    held open by that httpd child process and won't be reused.  If the
+    FastCGI application is able to handle concurrent connections
+    from httpd, you can opt-in to connection reuse as shown in the following
+    example:</p>
 
-    <example><title>Single application instance, no connection reuse</title>
+    <example><title>Single application instance, connection reuse</title>
     <highlight language="config">
-      ProxyPass /myapp/ fcgi://localhost:4000/ disablereuse=on
+      ProxyPass /myapp/ fcgi://localhost:4000/ disablereuse=off
       </highlight>
     </example>
 
     <p> The following example passes the request URI as a filesystem 
     path for the PHP-FPM daemon to run. The request URL is implicitly added 
     to the 2nd parameter. The hostname and port following fcgi:// are where
-    PHP-FPM is listening.</p>
+    PHP-FPM is listening.  Connection pooling is enabled.</p>
     <example><title>PHP-FPM</title>
     <highlight language="config">
-      ProxyPassMatch ^/myapp/.*\.php(/.*)?$ fcgi://localhost:9000/var/www/
+      ProxyPassMatch ^/myapp/.*\.php(/.*)?$ fcgi://localhost:9000/var/www/ disablereuse=off
     </highlight>
     </example>
 
@@ -101,7 +97,8 @@
     the hostname and optional port following fcgi:// are ignored.</p>
     <example><title>PHP-FPM with UDS</title>
     <highlight language="config">
-      ProxyPassMatch ^/(.*\.php(/.*)?)$ "unix:/var/run/php5-fpm.sock|fcgi://localhost/var/www/"
+      # UDS does not currently support connection reuse
+      ProxyPassMatch ^/(.*\.php(/.*)?)$ "unix:/var/run/php5-fpm.sock|fcgi://localhost/var/www/" 
     </highlight>
     </example>
 

Modified: httpd/httpd/trunk/modules/proxy/mod_proxy_fcgi.c
URL: http://svn.apache.org/viewvc/httpd/httpd/trunk/modules/proxy/mod_proxy_fcgi.c?rev=1647005&r1=1647004&r2=1647005&view=diff
==============================================================================
--- httpd/httpd/trunk/modules/proxy/mod_proxy_fcgi.c (original)
+++ httpd/httpd/trunk/modules/proxy/mod_proxy_fcgi.c Sat Dec 20 15:38:27 2014
@@ -834,11 +834,15 @@ static int proxy_fcgi_handler(request_re
         goto cleanup;
     }
 
-    /* XXX Setting close to 0 is a great way to end up with
-     *     timeouts at this point, since we lack good ways to manage the
-     *     back end fastcgi processes.  This should be revisited when we
-     *     have a better story on that part of things. */
+    /* This scheme handler does not reuse connections by default, to
+     * avoid tieing up a fastcgi that isn't expecting to work on 
+     * parallel requests.  But if the user went out of their way to
+     * type the default value of disablereuse=off, we'll allow it.
+     */  
     backend->close = 1;
+    if (worker->s->disablereuse_set && !worker->s->disablereuse) { 
+        backend->close = 0;
+    }
 
     /* Step Two: Make the Connection */
     if (ap_proxy_connect_backend(FCGI_SCHEME, backend, worker, r->server)) {