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Ryan_126004's avatar
Ryan_126004
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Jun 06, 2014

table command causing abort of rule event HTTP_REQUEST

Hello everyone, This is my first dig into iRules, and I'm hitting an issue with the table command that is aborting my rule. I'm essentially trying to rate limit requests per URI per ASPNET Session ...
application delivery
deployment
devops
iRules
LTM
session
table
nitass's avatar
nitass
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Pending rule event HTTP_REQUEST aborted for ... (listener: /Common/Drupal_HTTP)

i may be wrong but i think it means connection is terminated (for whatever reason) before irule is complete.

by the way, these are my comments.

1) for static variable (e.g. maxReqs, cooldownTimer, sampleTimer, timeout),

static

https://clouddocs.f5.com/api/irules/static.html

2) in No session cookie found. Quitting section, you may use "return" to exit the current event. event disable does not exit from the event.

event

https://clouddocs.f5.com/api/irules/event.html

 

 irule

[root@ve11a:Active:In Sync] config  tmsh list ltm rule qux
ltm rule qux {
    when HTTP_REQUEST {
  log local0. "priority 500: before"
  event HTTP_REQUEST disable
  log local0. "priority 500: after"
}
when HTTP_REQUEST priority 600 {
  log local0. "priority 600"
}
when HTTP_RESPONSE {
  log local0. "priority 500"
}
}

 /var/log/ltm

[root@ve11a:Active:In Sync] config  tail -f /var/log/ltm
Jun  8 11:45:34 ve11a info tmm[9801]: Rule /Common/qux HTTP_REQUEST: priority 500: before
Jun  8 11:45:34 ve11a info tmm[9801]: Rule /Common/qux HTTP_REQUEST: priority 500: after
Jun  8 11:45:35 ve11a info tmm[9801]: Rule /Common/qux HTTP_RESPONSE: priority 500

 

3) in set currCount [table add $key 1] section, when will table add return null?

table

https://clouddocs.f5.com/api/irules/table.html

Ryan_126004's avatar
Ryan_126004
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Jun 08, 2014
Thanks for the feedback on static variables and return versus event commands. I'll adjust my rule. If the rule is being aborted because the connection is terminated before it completes execution, then.. I'm a bit confused. Without the iRule, the web page loads just fine. Would this also be if the HTTP request completes before the rule is completely executed? When I access the server with the iRule in place, I get no response at all. Is there maybe a better event to trigger this on that would prevent these issues? I'm essentially trying to stop the connection to the backend server and return HTTP 429 is it hits too many requests per URI over 30 seconds. The currCount would return 0 if it's the first attempt at that URI for the current ASPNET Session ID in the last 30 seconds.