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brad9iner_11512's avatar
brad9iner_11512
Icon for Altostratus rankAltostratus
Feb 08, 2017

iRule to log how many requests are being caught by existing iRule

So I have an existing iRule that handles some redirecting of a specific context path over to the root context path:

when HTTP_REQUEST {
  set context_root "/audit"
  if { [HTTP::path] starts_with $context_root } {
    switch [HTTP::path] {
      "/audit" {
        HTTP::uri "/?[HTTP::query]"
        HTTP::path "/"
      }
      default {
        set substr_uri [substr [HTTP::uri] [string length $context_root]]
        set substr_path [substr [HTTP::path] [string length $context_root]]
        HTTP::uri $substr_uri
        HTTP::path $substr_path
      }
    }
  }
}

What I am wanting to capture are the source IPs of requests that are coming in with that /audit context path. Is it possible to add in some HSL to this existing iRule? Or would it be better to create a new HSL iRule to capture that traffic first before it gets captured by the above iRule?

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  • Kai_Wilke's avatar
    Kai_Wilke
    Icon for MVP rankMVP
    Feb 08, 2017

    Hi Brad,

    Performance-wise it's slightly more effective to integrate the HSL command into the existing iRule. In this case your F5 doesn't need to parse the HTTP::path twice to check if 

    /audit*
    is requested.

    Management-wise its up to you. Both approaches are absolute valid...

    The integration of HSL is rather simple. You may take a look to the iRule below to see how the HSL can be integrated in your existing iRule.

    when CLIENT_ACCEPTED {
  set hsl_handle [HSL::open -proto  -pool ]
}
when HTTP_REQUEST {
  set context_root "/audit"
  if { [HTTP::path] starts_with $context_root } {
    HSL::send $hsl_handle "<135> Audit access: [IP::client_addr]\n"
    switch [HTTP::path] {
      "/audit" {
        HTTP::uri "/?[HTTP::query]"
        HTTP::path "/"
      }
      default {
        set substr_uri [substr [HTTP::uri] [string length $context_root]]
        set substr_path [substr [HTTP::path] [string length $context_root]]
        HTTP::uri $substr_uri
        HTTP::path $substr_path
      }
    }
  }
}

    Cheers, Kai