[Catalyst] fastcgi, production catalyst and sigpipe

[Ruben Fonseca]

Hi! I have a Catalyst website in production, but started to hit some  
problems lately. But first a little about my configuration:

Catalyst website using the standard and the latest stable modules.
Linux + Apache 2 + fastcgi running in external mode.
fastcgi server (FCGIProcessManager) with 2 Catalyst children.

The problem is that, once a day, at random time, my application  
simply dies, and the only error I see on apache logs is:

FastCGI: server "/tmp/etrading-secure.fcgi" stderr : FastCGI: server  
(pid 8122): safe exit after SIGTERM, referer: https://__mysite__"

Digging on the situation, I put strace saving the system calls of  
both the fcgiprocessmanager (8120), and the 2 Catalyst children  
(8121, 8122) and found this:

- The first child (8121) receives a SIGPIPE and imediatly dies! Here  
are the last lines of strace before 8121 dies:

8121  18:17:20 write(4, "\1\6\0\1\26J\6\0\"POST\">\n\t\t\t\t\t<input  
type"..., 5744) = -1 EPIPE (Broken pipe)
8121  18:17:20 --- SIGPIPE (Broken pipe) @ 0 (0) ---

I thing SIGPIPE is sent when the client closes the connection before  
all data is sent by Catalyst. But why does it terminate?

- The process manager (8120) sees SIGPIPE and sends SIGTERM to the  
other child (8122). After the child dies, it turns itself down:

8120  15:42:58 waitpid(-1, [{WIFSIGNALED(s) && WTERMSIG(s) ==  
SIGPIPE}], 0) = 8121
8120  18:17:20 --- SIGCHLD (Child exited) @ 0 (0) ---
8120  18:17:20 write(2, "FastCGI: manager (pid 8120): ser"..., 69) = 69
8120  18:17:20 getppid()
(...)
8120  18:17:20 write(2, "FastCGI: manager (pid 8120): sen"..., 56) = 56
8120  18:17:20 kill(8122, SIGTERM)      = 0
8120  18:17:20 waitpid(-1, [{WIFEXITED(s) && WEXITSTATUS(s) == 0}],  
0) = 8122
8120  18:17:21 --- SIGCHLD (Child exited) @ 0 (0) ---
8120  18:17:21 write(2, "FastCGI: manager (pid 8120): ser"..., 68) = 68
8120  18:17:21 write(2, "FastCGI: manager (pid 8120): dyi"..., 61) = 61
(...)
8120  18:17:21 exit_group(0)            = ?

What do you think is wrong here? I think that the catalyst  
application should not die when it receives a SIGPIPE. But it could  
be another problem. Please advice me. If you need more information  
about my environment, please ask!

Cheers,
Rúben