DCheck failure if pagespeed is off and no file cache path is configured

[lbensaad]

I have followed the steps here:
https://developers.google.com/speed/pagespeed/module/downstream-caching
To configure proxy caching with pagespeed, but I found that when adding "pagespeed off" in the proxy_cache server configuration file then the cpu usage will be 100% and the site does not load, and when i remove it, it works fine.
The configuration file is here: https://gist.github.com/bml13/505e5bf840a9d09143d3

What could be wrong?

[oschaaf]

@bml13 I tried to reproduce based on your configuration with static content instead of wordpress, no luck yet. I'll try some more, but meantime I have a few questions:

• Could you post more details of your system, like the OS and pagespeed version?
• Is there anything noteworthy logged to nginx's error.log when nginx is in a state where it is taking 100% cpu (or before entering that state?).
• Does the problem show up immediately after starting nginx, or after you request one or more pages?

[lbensaad]

Sorry i forget to post them.
I am using Ubuntu 14.04.2 LTS, nginx 1.6.3, ngx_pagespeed 1.9.32.3-4448
The problem is that when I added "pagespeed off" and started nginx, then the nginx error log file gets full quickly with these lines that are repeated hundreds of times right after the start of nginx and even before loading any page, and since the cpu is 100% busy then no page will load at all:

2015/04/20 11:02:09 [alert] 11704#0: [ngx_pagespeed 1.9.32.3-4448] [0420/110209:FATAL:system_cache_path.cc(209)] Check failed: path.starts_with("/").
nginx: master process /usr/sbin/nginx() [0x51de19]
nginx: master process /usr/sbin/nginx() [0x51ae32]
nginx: master process /usr/sbin/nginx() [0xa0ab39]
nginx: master process /usr/sbin/nginx() [0x661983]
nginx: master process /usr/sbin/nginx() [0x66b678]
nginx: master process /usr/sbin/nginx() [0x4da6fd]
nginx: master process /usr/sbin/nginx() [0x4452a6]
nginx: master process /usr/sbin/nginx() [0x446062]
nginx: master process /usr/sbin/nginx(ngx_spawn_process+0x170) [0x444310]
nginx: master process /usr/sbin/nginx() [0x445c7d]
nginx: master process /usr/sbin/nginx(ngx_master_process_cycle+0x1e6) [0x446846]
nginx: master process /usr/sbin/nginx(main+0x77f) [0x424e4f]
/lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xf5) [0x7f7bedd3eec5]
nginx: master process /usr/sbin/nginx() [0x4253cf]

nginx: master process /usr/sbin/nginx() [0x51de19]
nginx: master process /usr/sbin/nginx() [0x4d51f0]
nginx: master process /usr/sbin/nginx() [0x51af14]
nginx: master process /usr/sbin/nginx() [0xa0ab39]
nginx: master process /usr/sbin/nginx() [0x661983]
nginx: master process /usr/sbin/nginx() [0x66b678]
nginx: master process /usr/sbin/nginx() [0x4da6fd]
nginx: master process /usr/sbin/nginx() [0x4452a6]
nginx: master process /usr/sbin/nginx() [0x446062]
nginx: master process /usr/sbin/nginx(ngx_spawn_process+0x170) [0x444310]
nginx: master process /usr/sbin/nginx() [0x445c7d]
nginx: master process /usr/sbin/nginx(ngx_master_process_cycle+0x1e6) [0x446846]
nginx: master process /usr/sbin/nginx(main+0x77f) [0x424e4f]
/lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xf5) [0x7f7bedd3eec5]
nginx: master process /usr/sbin/nginx() [0x4253cf]

[oschaaf]

Great thanks. I think I know what happens.
You should be able to disable pagespeed without having a valid FileCachePath configured,
but currently a check fails.

I suspect a workaround to this is moving this line into the http{} block:

pagespeed FileCachePath /var/run/ngx_pagespeed_cache;

[lbensaad]

Brilliant, It is solved.
Many thanks

[jmarantz]

Let's leave this open for now. The corresponding error in Apache I think would prevent Apache from starting up and give clean error message to stdout, rather than spinning the CPU and logging hex stack traces to the error log.

We should get the nginx failure-mode here to be a little easier to diagnose.

[jeffkaufman]

@crowell is looking at this

[crowell]

currently testing a fix that will go into mod_pagespeed, I'll reference this bug when it goes in.

[crowell]

fixed in mod_pagespeed commit apache/incubator-pagespeed-mod@b4a2ed8

[mital]

how can I fix this in my ngx_pagespeed ? I am using master branch and 1.9.32.3.tar.gz psol