Forum Discussion
Deon
Nimbostratus
NimbostratusMultiple iRule Redirects, event disable, TCP::close
We have multiple iRules and each can do a redirect based on a condition in HTTP_REQUEST event. I added an event disable after the redirect in each iRule so that I don't have multiple redirects happening. I just noticed a side effect with this setup in that the event remains disabled for the duration of the connection and if a subsequent request comes on the same connection then the iRule does not function like I desire it to. I realize this is because the event disable is scoped to the connection and not the particular request. I've read the posts that discuss setting a local variable and checking the value of that in the other iRules. This seems like a lot of logic to add to many different iRules. Is there an alternative way of doing this with TCP::close following the redirect?
What is the downside of the following with the TCP::close added?
when HTTP_REQUEST {
if { ([HTTP::uri] equals "/") } {
HTTP::redirect "https://www.mycompany.com/myapproot"
TCP::close
event disable
}
}
Thanks
-Deon
5 Replies
Michael_YatesHi Deon,
As you found out the "event disable" will disable the HTTP_REQUEST Event for the duration of the connection.
What you can do is a "return" to escape the event from further processing.
http://devcentral.f5.com/wiki/iRules.return.ashx
Give it a try and see if it corrects your issue.
Hope this helps.- nitass
Employee
What you can do is a "return" to escape the event from further processing.i understand return does not stop processing other event.
What is the downside of the following with the TCP::close added?i do not see any downside except client has to create a new tcp connection.[root@iris:Active] config b virtual bar list virtual bar { snat automap pool foo destination 172.28.17.33:http ip protocol tcp rules { myrule myrule2 } profiles { http {} tcp {} } } [root@iris:Active] config b rule myrule list rule myrule { when HTTP_REQUEST priority 100 { if {[HTTP::uri] equals "/"} { HTTP::redirect "http://172.28.17.33/myapproot" TCP::close event disable } log local0. "client [IP::remote_addr]:[TCP::remote_port], uri [HTTP::uri]" } } [root@iris:Active] config b rule myrule2 list rule myrule2 { when HTTP_REQUEST { log local0. "client [IP::remote_addr]:[TCP::remote_port], uri [HTTP::uri]" } } [root@iris:Active] config tail -f /var/log/ltm Oct 15 16:47:58 local/tmm info tmm[4601]: Rule myrule : client 192.168.206.102:62770, uri / since redirect was sent on existing tcp connection, http event was not triggered. [root@iris:Active] config b rule myrule list rule myrule { when HTTP_REQUEST priority 100 { if {[HTTP::uri] equals "/"} { HTTP::redirect "http://172.28.17.33/myapproot" TCP::close event disable } log local0. "client [IP::remote_addr]:[TCP::remote_port], uri [HTTP::uri]" } } [root@iris:Active] config tail -f /var/log/ltm Oct 15 17:09:48 local/tmm info tmm[4601]: Rule myrule : client 192.168.206.102:62848, uri / Oct 15 17:09:48 local/tmm info tmm[4601]: Rule myrule2 : client 192.168.206.102:62848, uri / Oct 15 17:09:48 local/tmm info tmm[4601]: Rule myrule : client 192.168.206.102:62849, uri /myapproot Oct 15 17:09:48 local/tmm info tmm[4601]: Rule myrule2 : client 192.168.206.102:62849, uri /myapproot [root@iris:Active] config b rule myrule list rule myrule { when HTTP_REQUEST priority 100 { if {[HTTP::uri] equals "/"} { HTTP::redirect "http://172.28.17.33/myapproot" TCP::close event disable } log local0. "client [IP::remote_addr]:[TCP::remote_port], uri [HTTP::uri]" } } [root@iris:Active] config tail -f /var/log/ltm Oct 15 17:11:40 local/tmm info tmm[4601]: Rule myrule : client 192.168.206.102:62860, uri / Oct 15 17:11:40 local/tmm info tmm[4601]: Rule myrule : client 192.168.206.102:62861, uri /myapproot Oct 15 17:11:40 local/tmm info tmm[4601]: Rule myrule2 : client 192.168.206.102:62861, uri /myapproot 
DeonHi nitass. Thanks for the assistance. I think your testing scenarios show the TCP::close and the event disable together accomplish what I need. I appreciate your help.
Magnum_IPIt is a happy day when you find the answer to the exact issue you are having on DevCentral ;-) The solution works like a charm. A thought that did cross my mind was if there was any potential performance hit from creating new tcp connections per request especially on an https virtual server? I will need to lab this up and run a test.
- Arie
Altostratus
Another option is to set a semaphore everywhere an iRule uses HTTP::response (HTTP::redirect counts as an HTTP::response). Although not as efficient, it does make it easier to prevent multiple responses - especially if there are multiple iRules and multiple iRule developers.
