Create F5 iRule namedhttp_mirroring to mirror HTTP requests to the new pool by copy/pasting our provided iRule
when RULE_INIT {
# Log debug locally to /var/log/ltm? 1=yes, 0=no
set static::hsl_debug 1
# Pool name to clone requests to
set static::hsl_pool "httpmirrorpool"
}
when CLIENT_ACCEPTED {
if {[active_members $static::hsl_pool]==0}{
log "[IP::client_addr]:[TCP::client_port]: [virtual name] $static::hsl_pool down, not logging"
set bypass 1
return
} else {
set bypass 0
}
# Open a new HSL connection if one is not available
set hsl [HSL::open -proto TCP -pool $static::hsl_pool]
if {$static::hsl_debug}{log local0. "[IP::client_addr]:[TCP::client_port]: New hsl handle: $hsl"}
}
when HTTP_REQUEST {
# If the HSL pool is down, do not run more code here
if {$bypass}{
return
}
# Insert an XFF header if one is not inserted already
# So the client IP can be tracked for the duplicated traffic
HTTP::header insert X-Forwarded-For [IP::client_addr]
# Check for POST requests
if {[HTTP::method] eq "POST"}{
# Check for Content-Length between 1b and 1Mb
if { [HTTP::header Content-Length] >= 1 and [HTTP::header Content-Length] < 1048576 }{
HTTP::collect [HTTP::header Content-Length]
} elseif {[HTTP::header Content-Length] == 0}{
# POST with 0 content-length, so just send the headers
HSL::send $hsl "[HTTP::request]\n"
if {$static::hsl_debug}{log local0. "[IP::client_addr]:[TCP::client_port]: Sending [HTTP::request]"}
}
} else {
# Request with no payload, so send just the HTTP headers to the clone pool
HSL::send $hsl "[HTTP::request]\n"
if {$static::hsl_debug}{log local0. "[IP::client_addr]:[TCP::client_port]: Sending [HTTP::request]"}
}
}
when HTTP_REQUEST_DATA {
# The parser does not allow HTTP::request in this event, but it works
set request_cmd "HTTP::request"
if {$static::hsl_debug}{log local0. "[IP::client_addr]:[TCP::client_port]: Collected [HTTP::payload length] bytes,\
sending [expr {[string length [eval $request_cmd]] + [HTTP::payload length]}] bytes total"}
HSL::send $hsl "[eval $request_cmd][HTTP::payload]\nf"
}
