Any way to keep apache proxy from timing out? - apache

I can't find in the docs if it's possible to keep apache from timing out on a proxy request. I'm trying to setup a socket server and am looking for this as an option.

Did you try ProxyTimeout directive, and set it to a relatively big number in seconds as specified in http://httpd.apache.org/docs/2.2/mod/mod_proxy.html#proxytimeout

Related

does Apache do any DNS lookups on the Host header

I have received some results from a security scan that say that something is executing DNS A record look-ups on the URL in the Host header.
Having looked at the application code I can't see any such requests so I'm looking further up the stack.
I don't think Apache should be doing this but it's using mod_headers and mod_rewrite and maybe there is a configuration item in there that I have overlooked.
A long time ago, I came across an Apache httpd that was configured to do a reverse-lookup for IP-addresses before logging. While this was long denied, some requests were served quickly, while others took a long time (depending on the time required for the reverse lookup). And it became obvious once we looked at the logs (DNS names mixed with IP-addresses)
I don't see any reason why Headers and Rewrite would ever need to resolve any of the domains - they're purely working on strings/regexp.
Recommendation to figure out what's going on: Capture the traffic and figure out what domains/addresses are looked up when. With DNS still being largely unencrypted, this might be fairly easy, and point you to the smoking gun.

Increase request timeout in Ember server

When using my Ember application in the Ember server ("ember serve"), any request that takes over 1.00 minutes fails with a 502 error. However, when I build my app, and use my local Apache server, requests don't fail for several minutes.
How do I increase the request timeout in Ember server? I don't see any options anywhere to set this value, nor can I find any sort of documentation online.
The following may help.
As specified here, you can add the timeout in ms in the hash returned by ajaxOptions in the adapter.
https://discuss.emberjs.com/t/how-to-set-ajax-timeout-for-ember-rsvp-or-store-findrecord/8386/4
They have also mentioned the limitation that If
If Ember stop receiding from Jquery, this will not be an option.
I fixed this myself. It wasn't a problem with Ember server after all. The problem was my ember proxy was pointing to an Apache server, which in-turn proxied the API server. The Apache ProxyPass setting was missing the timeout argument, so it was defaulting to 60 seconds. I needed to add a timeout to my ProxyPass setting in my httpd.conf file, like so:
ProxyPass /api https://localhost:8081/api timeout=180

Configure Access-Control-Allow-Origin for monit

I am trying to grab json data from monit and display it on a status page for management to see the current status of a handful of processes. This info would be displayed in Confluence running on the same machine but since Confluence (apache) and monit are running on different ports it is considered to be cross domain.
I know I can write a server side process to serve this data but that seems to be overkill and would actually take longer that it took to set monit up in the first place :)
The simplest solution is to configure monit's headers (Access-Control-Allow-Origin) to allow the other server. Does anyone know how to do this? I suspect there is a way since M/Monit would run into the same issue. I have tried some blind attempts on the "httpd... allow" lines but it complains about the syntax with x.x.x.x:port or using keyword "port" in that location.
ok... going to answer my own question (sort of).
First, I think I may have asked the question wrong. I don't deal with a lot of cross domain issues. Sorry about that.
But here is what I did to get to the monit info from the other servers: pretty simple using proxies in apache where the main server is:
ProxyPass /monit http://localhost:2812
ProxyPassReverse /monit http://mainserver/monit
ProxyPass /monit2 http://server2:2812
ProxyPassReverse /monit2 http://mainserver/monit2
I did this for each of the servers and tested that I can get to either the monit web interface or to the _status?format=json sub pages. I can now call them using ajax on our main web page.
This also has the benefit that I can lock down the monit access control to just the main server but have the info show on a more visible page. :)
I don't think you would need a proxy to just display monit's api or http info. It depends on how you have your network and dns configured. If you'd like to use only localhost, then that might be necessary. But, monit does have a facility to use global host ip access using allow directives in it's own config rc file

Apache timeout in perl CGI tool

I am running a Perl CGI tool that executes a system command (Unix) which may run for a few seconds up to an hour.
After the script is finished, the tool should display the results log on the screen (in a browser).
The problem is that after about 5 minutes I get a timeout message "Gateway Time-out" - the system command continue to run but I'm unable to display to the user the results of the run.
In the Apache config file (httpd.conf): Timeout 300.
Is there a simple way ordering the Apache to increase the timeout only for a specific run?
I don't really want to change the Apache timeout permanently (or should I?) and not dramatically update the code (a lot of regression tests).
Thanks in advance.
Mike
Make the script generate some output every once in a while. The timeout is not for running the program to completion, but is a timeout while Apache is waiting for data. So if you manage to get your program to output something regularly while running, you will be fine.
Note that HTTP clients, i.e. browsers, also have their own timeout. If your browser does not get any new data from the web server five minutes (typically), the browser will declare a timeout and give up even if the server is still processing. If your long running processing gives some output every now and then, it will help against browser timeouts too!
For completeness:
Though the accepted answer is the best (it's variously known as KeepAlive packets in TCP/IP, or Tickle packets way back in appletalk days) you did ask if you can do dynamic Apache config.
An apache module could do this. Oh, but that's a pain to write in C.
Remember that mod_perl (and to some extent mod_python, though it's deprecated) do not only handlers but wrap the internal config in perl as well. You could write something complicated to increase the timeout in certain situations. But, this would be a bear to write and test, and you're better off doing what Krisku says.
There doesn't seem to be any way to specify a timeout on the <!--#include virtual=... --> directive, but if you use mod_cgid instead of mod_cgi then starting with Apache 2.4.10 there's a configurable timeout parameter available which you can specify in httpd.conf or .htaccess:
CGIDScriptTimeout nnns
...where nnn is the number of seconds that Apache will allow a cogitating CGI script to continue to run.
Caveat: If you use PHP with Apache, then your Apache is presumably configured in /etc/httpd/conf.modules.d/00-mpm.conf to use "prefork" MPM (because PHP requires it unless built with thread-safe flags), and the default Apache installation used mod_cgi with the prefork MPM, so you'll probably need to edit /etc/httpd/conf.modules.d/01-cgi.conf to tell Apache to use mod_cgid instead of mod_cgi.
Although the comment in 01-cgi.conf says, "mod_cgid should be used with a threaded MPM; mod_cgi with the prefork MPM," that doesn't seem to be correct, because mod_cgid seems to work fine with prefork MPM and PHP, for me, with Apache 2.4.46.
Although that doesn't give you complete control over server timeouts, you could specify a different CGIDScriptTimeout setting for a particular directory (e.g., put your slow .cgi files in the ./slowstuff/ folder).
(Of course, as krisku mentioned in the accepted answer, changing CGIDScriptTimeout won't solve the problem of the user's web browser timing out.)

Apache Mod_cache configuration with Tomcat and Max-age directives

I have the following system configured:
Tomcat -> Apache
Now, I have some URLs on which I have Max-Age, LastModified and Etags set.
My expectation is when Client1 makes a call to the server, the page should get served from tomcat, but should get cached in the mod_cache module of Apache. So that when next client makes a call, the page is served from Apache and it doesnt have to hit the Tomcat server, if the page is still fresh. If the page isnt fresh, Apache should make a Conditional Get to validate the content it has.
Can someone tell me if there is any fundamental mistake in this thinking? It doesnt happen to work that way. In my case, when client2 makes a call, it goes straight to the Tomcat server(not even a Conditional Get).
Is my thinking incorrect or my Apache configuration incorrect?! Thanks
The "What can be cached" section of the docs has a good summary of factors - such as response codes, GET request, presence of Authorization header and so on - which permit caching.
Also, set the Apache LogLevel to debug in httpd.conf, and you will get a clear view of whether or not each request got cached. Check the error logs.
You should be able to trace through what is happening based on these two.