Custom 503 Error Page

[Douglas A. Seifert]

> > > > Hmm... that doesn't seem to work either.  Is it possible that `return xxx;` 
> > > > always generates the internal response?
> > > >
> > > > The only thing that would achieve the desired result in this case is 
> > > > proxying to some blackhole which would cause the 503 to be caught and 
> > > > rewritten according to the error_page directive.
> > > 
> > > Oops. Sorry, I missed. The real problem is that with suggested 
> > > configuration (i.e. always return 503 at server level) there 
> > > is no way to reach /system/maintenance.html file for nginx.
> > > 
> > > So, it tries to get /system/maintenance.html for error body, and 
> > > gets yet another 503. So it has to return hardcoded content.
> > > 
> > > The only solution is to allow nginx to access 
> > > /system/maintenance.html somehow. Something like this:
> > > 
> > >      error_page 503 /system/maintenance.html;
> > > 
> > >      location / {
> > >          if (-f ...) {
> > >              return 503;
> > >          }
> > >      }
> > > 
> > >      location /system/maintenance.html {
> > >          # allow requests here - do not return 503
> > >      }
> > > 
> > > The if{} block should be in all locations where access should be 
> > > disallowed, but not for /system/maintenance.html itself.
> > > 
> > > Maxim Dounin
> > > 
> > 
> > Doing it that way gets me the custom content, but with a 200 OK
> > response. :(  I'm afraid the only way I will be able to do this is to
> > recompile nginx with the default 503 content set to what I want it to be
> > (that's my current workaround).  Or dig up my extremely rusty C skills
> > and try to figure out the bug, if any.
> 
> The way suggested by Maxim should work. Are you sure that yo do not use
> 
>      error_page 503 = /system/maintenance.html;
> 
> instead of
> 
>      error_page 503 /system/maintenance.html;
> 

I had forgotten to pull the rewrite directive out of the if:

I had 

if (-f ...) {
  rewrite ^(.*)$ /system/maintenance.html last;
  return 503;
}

Taking the rewrite directive out fixed it.

For those interested, the final config that does what I want is below.
I imagine a more complicated config will be harder to deal with because
I will have to make sure the check for the maintenance page stays out of
the top level of the config.

test.conf
----------------------------------------
# user and group to run as
#user  www www;

# number of nginx workers
worker_processes  6;

# pid of nginx master process
pid /usr/local/www/nginx.pid;

# Number of worker connections. 1024 is a good default
events {
  worker_connections 1024;
}

# start the http module where we config http access.
http {
  # pull in mime-types. You can break out your config 
  # into as many include's as you want to make it cleaner
  include /usr/local/nginx/conf/mime.types;

  # set a default type for the rare situation that
  # nothing matches from the mimie-type include
  default_type  application/octet-stream;

  # configure log format
  log_format main '$remote_addr - $remote_user [$time_local] '
                  '"$request" $status  $body_bytes_sent "$http_referer"
'
                  '"$http_user_agent" "$http_x_forwarded_for"';

  # main access log
  access_log  /usr/local/www/log/nginx_access.log  main;

  # main error log
  error_log  /usr/local/www/log/nginx_error.log debug;

  # no sendfile on OSX
  sendfile on;

  # These are good default values.
  tcp_nopush        on;
  tcp_nodelay       off;
  # output compression saves bandwidth 
  gzip            on;
  gzip_http_version 1.0;
  gzip_comp_level 2;
  gzip_proxied any;
  gzip_types      text/plain text/html text/css application/x-javascript
text/xml application/xml application/xml+rss text/javascript;

 server {

    # port to listen on. Can also be set to an IP:PORT
    listen *:8080;
    
    # Set the max size for file uploads to 50Mb
    client_max_body_size 50M;

    # sets the domain[s] that this vhost server requests for
    server_name .foo.com *;

    # doc root
    root /usr/local/www/test;

    # vhost specific access log
    access_log  /usr/local/www/log/nginx.vhost.access.log  main;

    # this rewrites all the requests to the maintenance.html
    # page if it exists in the doc root. This is for capistrano's
    # disable web task
    error_page   500 502 504  /500.html;
    error_page   503 /system/maintenance.html;
    location /system/maintenance.html {
      # Allow requests
    }

    location / {
      if (-f $document_root/system/maintenance.html) {
        return 503;
      }
    }

  }

}
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