====== Health Monitor use TCL ======
A10 support [[http://zh.wikipedia.org/wiki/Tcl|TCL]] (Tool Command Language) to scripting health check with youself.

===== THE NOTICE FOR TCL =====
  - In A10, make sure you filaname have extension that is ".tcl"!
  - If you are just searching for a fixed sequence of characters, use string operations.
  - If you are searching for a pattern, then use [[http://en.wikipedia.org/wiki/Regular_expression|regexp]](regular expressions).

===== Config Guide Example =====
Here is copy from config guide. It open a socket connect to HTTP, and get /1.html then paeser a string.
<code tcl http_check.tcl>
# Init server status to "DOWN"
set ax_env(Result) 1
# Open a socket
if {[catch {socket $ax_env(ServerHost) $ax_env(ServerPort)} sock]} {
  puts stderr "$ax_env(ServerHost): $sock"
} else {
  fconfigure $sock -buffering none -eofchar {}
  # Send the request
  puts $sock "GET /1.html HTTP/1.0\n"
  # Wait for the response from http server
  set line [read $sock]
  if { [ regexp "HTTP/1.. (\[0-9\]+) " $line match status] } {
    puts "server $ax_env(ServerHost) response : $status"
    # Check exit code
    if { $status == 200 } {
      # Set server to be "UP"
      set ax_env(Result) 0
    }
  }
  close $sock
}
</code>

===== Check for TCP socket =====
<code tcl tcp_check.tcl>
# Init server status to "DOWN"
set ax_env(Result) 1
# Open a socket
if {[catch {socket $ax_env(ServerHost) $ax_env(ServerPort)} sock]} {
  puts stderr "$ax_env(ServerHost): $sock"
} else {
  fconfigure $sock -buffering none -eofchar {}
  # Send the request "some_string" and return
  puts $sock "talk\n"
  # Wait for the response from TCP service
  set line [read $sock]
  if { [ regexp "Works" $line ] } {
    # Set server to be "UP"
    set ax_env(Result) 0
  }
  close $sock
}
</code>