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Problem this snippet solves:

This iRule uses the STATS profile to manage an LTM maintenance page response during maintenance windows.

Implementation details here:

Code :

  set TITLE "iRule Maintenance Window Control"
  set PROFILE_NAME "maintenance_window"

  # Look for embedded commands to control the maintenance window.

  switch -glob [string tolower [HTTP::uri]] {
    "/enable*" {

      # Extract the maintenance window day, start time, and end time from the URI. 
      # If not there, return an error message.

      set params [split [HTTP::uri] "/"]
      if { [llength $params] < 5 } {
        HTTP::respond 200 content "

Usage: http://[HTTP::host]/enable/day_number/start_hour/end_hour

" } else { # Update the maintenance window values in the statistics profile. STATS::set $PROFILE_NAME "day" [lindex $params 2] STATS::set $PROFILE_NAME "start_time" [lindex $params 3] STATS::set $PROFILE_NAME "end_time" [lindex $params 4] HTTP::respond 200 content "

Maintenance Window enabled

" } } "/disable" { # By zero'ing out the values in the statistics profile, the maintenance window is not enforced. STATS::set $PROFILE_NAME "day" 0 STATS::set $PROFILE_NAME "start_time" 0 STATS::set $PROFILE_NAME "end_time" 0 HTTP::respond 200 content "

Maintenance Window disabled

" } "/check" { # Return the current time and the current settings for the maintenance window set day [STATS::get $PROFILE_NAME "day"] set start_time [STATS::get $PROFILE_NAME "start_time"] set end_time [STATS::get $PROFILE_NAME "end_time"] set l [split [clock format [clock seconds] -format {%u %H %M}] " "] set cur_day [lindex $l 0] set cur_time [expr [expr [lindex $l 1]*100] + [lindex $l 2]] HTTP::respond 200 content "

Current Date and time: $cur_day, $cur_time

Maintenance Window: $day, $start_time - $end_time

" } "/usage" { # Usage instructions for the commands HTTP::respond 200 content "

Usage: http://[HTTP::host]/\[command\]

  • /enable/day_of_week_number(1:mon-7:sun)/start_time(hhmm)/end_time(hhmm) - enable maintenance window.
  • /disable - disable maintenance window.
  • /check - check if in maintenance window.
  • /usage - display this usage message
" } default { # no secret command entered, so check the maintenance window # Get the values from the statistics profile. set day [STATS::get $PROFILE_NAME "day"] set start_time [STATS::get $PROFILE_NAME "start_time"] set end_time [STATS::get $PROFILE_NAME "end_time"] if { ($day ne 0) and ($start_time ne 0) and ($end_time ne 0) } { # Use the TCL "clock" command to get the current time settings. set l [split [clock format [clock seconds] -format {%u %H %M}] " "] set cur_day [lindex $l 0] set cur_time [expr [expr [lindex $l 1]*100] + [lindex $l 2]] if { ($cur_day eq $day) && ($cur_time >= $start_time) && ($cur_time <= $end_time) } { # The current time is in the maintenance window, so either issue a HTTP::redirect here to a # prettied up page, or you can do as I've done here, and return a HTML response direction # to the client. HTTP::respond 200 content "

This site is down for maintenance, please come back at $end_time ...

" } else { # Not in maintenance window, so allow connection to continue to application. } } } } }
Version history
Last update:
‎18-Mar-2015 12:44
Updated by: