Multi-part Irule

Hi Kevin,

I think this will work for you. If you run into any issues, check /var/log/ltm for debug output. You can add more debug statements to see what's happening. Once you're done testing, you can comment out the log statements to save resources.

 
 when HTTP_REQUEST { 
  
    log local0. "[IP::client_addr]:[TCP::client_port]: New request to [HTTP::uri]" 
  
     Check if URI contains /forms 
    if {[HTTP::uri] contains "/forms"} { 
  
       log local0. "[IP::client_addr]:[TCP::client_port]: active members: [active_members SECOND_POOL]" 
  
        Use the second pool if it has available members 
       if {[active_members SECOND_POOL] > 0}{ 
          pool SECOND_POOL 
  
       } else { 
           Second pool was down, so use the third pool 
          pool THIRD_POOL 
       } 
    } 
 } 
 

Aaron

Thanks for your help, man! I'll test everything out and reply with the outcome.

 

 

Kevin

Well, that worked wonderfully! Thanks again for your help. Unfortunately, and as always, the plot thickens.

 

 

The guy I had originally discussed this change with didn't give me all the facts. Here be the situation:

 

 

Any http request coming into "http://www.site1.org/forms" must be somehow be redirected to "http://www.site2.com/forms".

 

 

The problem is that "/forms/" has subdirectories. Therefore I don't think a simple redirect will do the trick. Also, since it's the URL which needs changed and not just the uri, a uri rewrite won't work either. I tried it but was unsuccessful. Is there a way to do some kind of partial URL rewrite while still leaving "/forms/..." and trailing subdirectories intact?

 

 

For example, the iRule you put together for me would take a request for "www.site1.org/forms/sub1/sub2" and redirect it to "www.site2.org/forms" without keeping "/sub1/sub2".

 

 

Is this even possible?

Can you list out the logic for what should be redirected to a new URL, what should be sent to a pool and what if anything you want rewritten as before the request is sent to the pool? If you can include the Host and/or URI checks you want to use, we can provide some more examples.

 

 

In general, you can get the host value using HTTP::host, you can get the URI using HTTP::uri, you can issue a redirect using HTTP::redirect, and you can specify a pool using the pool command.

 

 

The wiki pages have more detail on the commands (Click here).

 

 

Aaron

Here's some slightly updated code:

 

 

 

 
 when HTTP_REQUEST {  
   log local0. "[IP::client_addr]:[TCP::client_port]: New request to [HTTP::uri]"  
    Check if URI contains /forms  
   if {[HTTP::uri] starts_with "/forms"} {  
     if { [HTTP::host ne "site2.com" } { 
       HTTP::redirect "http://site2.com[HTTP::uri]" 
     } else { 
       log local0. "[IP::client_addr]:[TCP::client_port]: active members: [active_members SECOND_POOL]"  
        Use the second pool if it has available members  
       if {[active_members SECOND_POOL] > 0}{  
         pool SECOND_POOL  
       } else {  
         Second pool was down, so use the third pool  
        pool THIRD_POOL  
       }  
     }  
   } 
 } 
 

 

 

Basically this is the same iRule, except that it performs a host check, too. Basically, you set both domains to point to the VIP address. Then, when traffic comes in from site1.org with /forms at the start of the URI, it will do an HTTP redirect to site2.com while maintaining the exact same URI (we already know it contains forms, so we don't need to rebuild it or strip forms out or anything, we just keep the whole thing intact as is). It will then hit the same VIP, again, and process through the second half of the iRule, as it won't get caught by the Host check this time. Now it'll hit the pool logic portion that elah built for you, and everyone should be happy.

 

 

Make sense?

 

 

Colin