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Forum Discussion

JackRodriguez's avatar
JackRodriguez
Icon for Nimbostratus rankNimbostratus
Apr 19, 2016

iRule to define pool names based on URI mapped to a value in a data group.

I have a need to configure a iRule that can take a portion of the URI and search a data group and then take the mapped value and use that in the creation of the pool name. I am not a coder and I thought this would be a fairly easy iRule to find an example but as it turned out, I could not find anything very close. I was able to "Frankenstein" a iRule together from multiple other iRule examples and I was finally able to get this working. The thing that I am most worried about however is the efficiency of my code and am I making the proper use of the "matchclass" and "class match". I took many of these examples from iRules that were written for V9 and V10 and I wonder if there is a more efficient/elegant way to write this iRule for what I am trying to accomplish. Thank you in advance.

 

when HTTP_REQUEST {
  if {[matchclass [string tolower [HTTP::path]] contains APP_DEV_uri_pool_map]} {
    set poolName "APP-BW-DEV-[class match -value [string tolower [HTTP::path]] contains APP_DEV_uri_pool_map]"
        pool $poolName
    if { $poolName equals "APP-BW-DEV-" } {
       log -noname local0.warn "uri-map-lookup-failed: from: [IP::remote_addr] for request: [HTTP::host] [HTTP::uri]"
     HTTP::respond 404 content {
  
  
  Not found
  
  Not found
  The requested page or resource was not found.
 
 }
}
}
}

Data Group

 

APP_DEV_uri_pool_map 


/pub_lead2lease := LEAD2LEASE-9001
/pub_omsorderservicev1 := OMS-ORDERS-9002
/pub_productservicev1 := OMS-PRODUCTS-9003
application delivery
data group
define pool name based on uri
iRules
LTM
matchclass
value lookup

1 Reply

  • cjunior's avatar
    cjunior
    Icon for Nacreous rankNacreous
    Apr 19, 2016

    Hi, according to documentation, "class match" is more performatic than "matchclass".

    https://devcentral.f5.com/wiki/irules.class.ashx

    I think you did a good job and I just made some changes which sounds better to me.

    when HTTP_REQUEST {
    set value [class match -value [string tolower [HTTP::path]] contains APP_DEV_uri_pool_map]
    if { $value ne "" } {
        pool APP-BW-DEV-$value
    } else {
        log local0. "uri-map-lookup-failed: from: [IP::remote_addr] for request: [HTTP::host] [HTTP::uri]"
        HTTP::respond 404 content {
            
            
            Not found
            Not found
            The requested page or resource was not found.
            
        }
    }
    unset value
}

    Maybe it should be improved with pool selection check.

    https://devcentral.f5.com/articles/irules-101-07-catch 
    when HTTP_REQUEST {
    set value [class match -value [string tolower [HTTP::path]] contains APP_DEV_uri_pool_map]
    if { $value ne "" } {
        if { [catch { pool APP-BW-DEV-$value }]  } {
            log local0.warn "uri-map-selection-failed: from: [IP::remote_addr] for request: [HTTP::host] [HTTP::uri] pool: APP-BW-DEV-$value"
            HTTP::respond 500 content {
                
                
                Internal Server Error
                Internal Server Error
                The server encountered an internal error or misconfiguration and was unable to complete your request.
                
            }
        }
    } else {
        log local0.notice "uri-map-lookup-failed: from: [IP::remote_addr] for request: [HTTP::host] [HTTP::uri]"
        HTTP::respond 404 content {
            
            
            Not found
            Not found
            The requested page or resource was not found.
            
        }
    }
    unset value
}

    Respectfully,