This ESM syslog filter module example watches for a single mnemonic (supplied via the first CLI argument) and escalates the severity of the message to that specified by the second CLI argument.

#  ===================================================================
#  Embedded Syslog Manager                           ||        ||
#                                                    ||        ||
#  Severity Escalation Filter                       ||||      ||||
#                                               ..:||||||:..:||||||:..
#                                              ------------------------
#                                              C i s c o  S y s t e m s 
#  ====================================================================
#
# Usage: Set CLI Args to "mnemonic new_severity"
#
# Namespace: global
# Check for null message
if { [string length $::orig_msg] == 0} {
   return ""
}
 
if { [info exists ::cli_args] } {
    set args [split $::cli_args]
    if { [ string compare -nocase [lindex $args 0] $::mnemonic ] == 0 } {
        set ::severity [lindex $args 1]
        set sev_index [ string first [lindex $args 0] $::orig_msg ] 
        if {  $sev_index >= 2 } {
           incr sev_index -2
           return [string replace $::orig_msg $sev_index $sev_index \
              [lindex $args 1]]
        }
    }
}
return $::orig_msg

This ESM syslog filter module example is divided into two files for readability. The first file allows the user to configure those messages that they want to count and how often to summarize (correlation window) by populating the msg_to_watch array. The actual procedures are in the counting_guts.tcl file. Note the use of the separate namespace “counting” to avoid conflict with other ESM filters that may also perform background processing.

#  ===================================================================
#  Embedded Syslog Manager                           ||        ||
#                                                    ||        ||
#  Message Counting Filter                          ||||      ||||
#                                               ..:||||||:..:||||||:..
#                                              ------------------------
#                                              C i s c o  S y s t e m s 

# ====================================================================

#
# Usage: 
# 1) Define the location for the counting_guts.tcl script
#
# 2) Define message categories to count and how often to dump them (sec)
#    by populating the "msg_to_watch" array below.
#    Here we define category as facility-severity-mnemonic
#    Change dump time to 0 to disable counting for that category
#
# Namespace: counting
namespace eval ::counting {
    set sub_script_url tftp://172.16.0.0/12/ESM/counting_guts.tcl
    array set msg_to_watch {
        SYS-5-CONFIG_I            5
    }
#  ======================= End User Setup ==============================
# Initialize processes for counting
    if { [info exists init] == 0 } {
       source $sub_script_url
       set position $module_position
    }
# Process the message
process_category
} ;# end namespace counting

Message Counting Support Module (counting_guts.tcl)

#  ===================================================================
#  Embedded Syslog Manager                           ||        ||
#                                                    ||        ||
#  Message Counting Support Module                  ||||      ||||
#                                               ..:||||||:..:||||||:..
#  (No User Modification)                      ------------------------
#                                              C i s c o  S y s t e m s 

# ====================================================================

 
 
namespace eval ::counting {
 
# namespace variables
 
array set cat_msg_sev {}
array set cat_msg_traceback {}
array set cat_msg_pid {}
array set cat_msg_proc {}
array set cat_msg_ts {}
array set cat_msg_buginfseq {}
array set cat_msg_name {}
array set cat_msg_fac {}
array set cat_msg_format {}
array set cat_msg_args {}
array set cat_msg_count {}
array set cat_msg_dump_ts {}
 
# Should I count this message ?
   proc query_category {cat} {
        variable msg_to_watch
        if { [info exists msg_to_watch($cat)] } {
            return $msg_to_watch($cat)
        } else {
            return 0
        }
    }
   proc clear_category {index} {
        variable cat_msg_sev 
        variable cat_msg_traceback
        variable cat_msg_pid
        variable cat_msg_proc
        variable cat_msg_ts 
        variable cat_msg_buginfseq 
        variable cat_msg_name 
        variable cat_msg_fac
        variable cat_msg_format 
        variable cat_msg_args 
        variable cat_msg_count 
        variable cat_msg_dump_ts
        unset cat_msg_sev($index) cat_msg_traceback($index) cat_msg_pid($index)\
              cat_msg_proc($index) cat_msg_ts($index) \
              cat_msg_buginfseq($index)  cat_msg_name($index) \
              cat_msg_fac($index) cat_msg_format($index) cat_msg_args($index)\
              cat_msg_count($index) cat_msg_dump_ts($index)
    }
# send out the counted messages
   proc dump_category {category} {
        variable cat_msg_sev 
        variable cat_msg_traceback
        variable cat_msg_pid
        variable cat_msg_proc
        variable cat_msg_ts 
        variable cat_msg_buginfseq 
        variable cat_msg_name 
        variable cat_msg_fac
        variable cat_msg_format 
        variable cat_msg_args 
        variable cat_msg_count 
        variable cat_msg_dump_ts
        variable poll_interval
        set dump_timestamp [cisco_service_timestamp]
foreach index [array names cat_msg_count $category] {
      set fsm "$cat_msg_fac($index)-$cat_msg_sev($index)-$cat_msg_name($index)"
      set ::orig_msg \
        [format "%s%s: %%%s: %s %s %s %s - (%d occurence(s) between %s and %s)"\
        $cat_msg_buginfseq($index)\
          $dump_timestamp\
          $fsm \
          [uplevel 1 [linsert $cat_msg_args($index) 0 ::format
$cat_msg_format($index) ]] \
          $cat_msg_pid($index) \
          $cat_msg_proc($index) \
          $cat_msg_traceback($index) \
          $cat_msg_count($index) \
          $cat_msg_ts($index) \
          $dump_timestamp]
# Prepare for remaining ESM filters
                set ::severity $cat_msg_sev($index)
                set ::traceback $cat_msg_traceback($index)
                set ::pid $cat_msg_pid($index)
                set ::process $cat_msg_proc($index)
                set ::timestamp $cat_msg_ts($index)
                set ::buginfseq $cat_msg_buginfseq($index)
                set ::mnemonic $cat_msg_name($index)
                set ::facility $cat_msg_fac($index)
                set ::format_string $cat_msg_format($index)
                set ::msg_args [split $cat_msg_args($index)]
                esm_errmsg $counting::position
                clear_category $index 
        }
  }
# See if this message already has come through since the last dump.
# If so, increment the count, otherwise store it.
   proc process_category {} {
        variable cat_msg_sev 
        variable cat_msg_traceback
        variable cat_msg_pid
        variable cat_msg_proc
        variable cat_msg_ts 
        variable cat_msg_buginfseq 
        variable cat_msg_name 
        variable cat_msg_fac
        variable cat_msg_format 
        variable cat_msg_args 
        variable cat_msg_count 
        variable cat_msg_dump_ts
        if { [string length $::orig_msg] == 0} {
           return ""
        }
        set category "$::facility-$::severity-$::mnemonic"
        set correlation_window [expr [ query_category $category ] * 1000]
        if { $correlation_window == 0 } {
            return $::orig_msg
        } 
        set message_args [join $::msg_args]
        set index "$category,[lindex $::msg_args 0]" 
        if { [info exists cat_msg_count($index)] } {
                 incr cat_msg_count($index)
         } else {
              set cat_msg_sev($index) $::severity
              set cat_msg_traceback($index) $::traceback
              set cat_msg_pid($index) $::pid
              set cat_msg_proc($index) $::process
              set cat_msg_ts($index) $::timestamp
              set cat_msg_buginfseq($index) $::buginfseq
              set cat_msg_name($index) $::mnemonic
              set cat_msg_fac($index) $::facility
              set cat_msg_format($index) $::format_string
              set cat_msg_args($index) $message_args
              set cat_msg_count($index) 1
              set cat_msg_dump_ts($index) [clock seconds]
              catch [after $correlation_window counting::dump_category $index]
         }
         return ""
   }
# Initialized
set init 1
} ;#end namespace counting

This ESM syslog filter module applies user-defined XML tags to syslog messages:

#  ===================================================================
#  Embedded Syslog Manager                           ||        ||
#                                                    ||        ||
#  XML Tagging Filter                               ||||      ||||
#                                               ..:||||||:..:||||||:..
#                                             ------------------------
#                                             C i s c o  S y s t e m s 
#  ===================================================================
#
# Usage: Define desired tags below.
#
# Namespace: xml
# Check for null message
    if { [string length $::orig_msg] == 0} {
       return ""
    }
namespace eval xml {
####  define tags ####
set MSG_OPEN "<ios-log-msg>"
set MSG_CLOSE "</ios-log-msg>"
set FAC_OPEN   "<facility>"
set FAC_CLOSE  "</facility>"
set SEV_OPEN   "<severity>"
set SEV_CLOSE  "</severity>"
set MNE_OPEN   "<msg-id>"
set MNE_CLOSE  "</msg-id>"
set SEQ_OPEN   "<seq>"
set SEQ_CLOSE  "</seq>"
set TIME_OPEN  "<time>"
set TIME_CLOSE "</time>"
set ARGS_OPEN  "<args>"
set ARGS_CLOSE "</args>"
set ARG_ID_OPEN "<arg id="
set ARG_ID_CLOSE "</arg>"
set PROC_OPEN "<proc>"
set PROC_CLOSE "</proc>"
set PID_OPEN "<pid>"
set PID_CLOSE "</pid>"
set TRACE_OPEN "<trace>"
set TRACE_CLOSE "</trace>"
#  ======================= End User Setup ==============================
#### clear result ####
set result ""
#### message opening, facility, severity, and name ####
append result $MSG_OPEN $FAC_OPEN $::facility $FAC_CLOSE $SEV_OPEN $::severity
$SEV_CLOSE $MNE_OPEN $::mnemonic $MNE_CLOSE
#### buginf sequence numbers ####
if { [string length $::buginfseq ] > 0 } {
    append result $SEQ_OPEN $::buginfseq $SEQ_CLOSE
}
#### timestamps ####
if { [string length $::timestamp ] > 0 } {
    append result $TIME_OPEN $::timestamp $TIME_CLOSE
}
#### message args ####
if { [info exists ::msg_args] } {
    if { [llength ::msg_args] > 0 } {
        set i 0
        append result $ARGS_OPEN 
        foreach arg $::msg_args { 
            append result $ARG_ID_OPEN $i ">" $arg $ARG_ID_CLOSE
                incr i
        }
        append result $ARGS_CLOSE 
    }
}
#### traceback ####
if { [string length $::traceback ] > 0 } {
    append result $TRACE_OPEN $::traceback $TRACE_CLOSE
}
#### process ####
if { [string length $::process ] > 0 } {
    append result $PROC_OPEN $::process $PROC_CLOSE
}
#### pid ####
if { [string length $::pid ] > 0 } {
    append result $PID_OPEN $::pid $PID_CLOSE
}
#### message close ####
append result $MSG_CLOSE
return "$result"
} ;# end namespace xml

This ESM syslog filter module example watches for configuration messages and sends them to the e-mail address supplied as a CLI argument. This filter is divided into two files. The first file implements the filter, and the second file implements the Simple Mail Transfer Protocol (SMTP) client.

#  ===================================================================
#  Embedded Syslog Manager                           ||        ||
#                                                    ||        ||
#  Email Filter                                     ||||      ||||
#  (Configuration Change Warning)               ..:||||||:..:||||||:..
#                                             ------------------------
#                                              C i s c o  S y s t e m s 
#   ===================================================================
# Usage:  Provide email address as CLI argument.  Set email server IP in
#         email_guts.tcl
#
# Namespace: email
if { [info exists email::init] == 0 } {
   source tftp://123.123.123.123/ESM/email_guts.tcl
}
# Check for null message
if { [string length $::orig_msg] == 0} {
      return ""
   }
if { [info exists ::msg_args] } {
    if { [string compare -nocase CONFIG_I $::mnemonic ] == 0 } {
                email::sendmessage $::cli_args $::mnemonic \
                [string trim $::orig_msg]
    }
}
return $::orig_msg

E-Mail Support Module (email_guts.tcl)

#  ===================================================================
#  Embedded Syslog Manager                           ||        ||
#                                                    ||        ||
#  Email Support Module                             ||||      ||||
#                                               ..:||||||:..:||||||:..
#                                             ------------------------
#                                              C i s c o  S y s t e m s 
#   ===================================================================
#
# Usage: Set email host IP, from, and friendly strings below.
#
namespace eval email {
    set sendmail(smtphost)172.16.0.1 
    set sendmail(from) $::hostname
    set sendmail(friendly) $::hostname
    proc sendmessage {toList subject body} {
        variable sendmail
        set smtphost $sendmail(smtphost)
        set from $sendmail(from)
        set friendly $sendmail(friendly)
        set sockid [socket $smtphost 25]
## DEBUG
set status [catch { 
        puts $sockid "HELO $smtphost"
        flush $sockid
        set result [gets $sockid]
        puts $sockid "MAIL From:<$from>"
        flush $sockid
        set result [gets $sockid]
        foreach to $toList {
            puts $sockid "RCPT To:<$to>"
            flush $sockid
        }
        set result [gets $sockid]
        puts  $sockid "DATA "
        flush $sockid
        set result [gets  $sockid]
        puts  $sockid "From: $friendly <$from>"
        foreach to $toList {
            puts $sockid "To:<$to>"
        }
        puts  $sockid "Subject: $subject"
        puts  $sockid "\n"
        foreach line [split $body "\n"] {
            puts  $sockid " $line"
        }
        puts  $sockid "."
        puts  $sockid "QUIT"
        flush $sockid
        set result [gets  $sockid]
} result]
        catch {close $sockid }
    if {$status} then {
        return -code error $result
    }
}
} ;# end namespace email
set email::init 1

This ESM syslog filter module example watches for a given facility (first CLI argument) and routes these messages to a given stream (second CLI argument:.

#  ===================================================================
#  Embedded Syslog Manager                           ||        ||
#                                                    ||        ||
#  Stream Filter (Facility)                         ||||      ||||
#                                               ..:||||||:..:||||||:..
#                                             ------------------------
#                                              C i s c o  S y s t e m s 
#   ===================================================================
# Usage:  Provide facility and stream as CLI arguments. 
#
# Namespace: global
# Check for null message
#  ======================= End User Setup ==============================
set args [split $::cli_args]
if { [info exists ::msg_args] } {
    if { $::facility == [lindex $args 0] } {
                set ::stream [lindex $args 1]
    }
}
return $::orig_msg} 

The logging source-interface CLI command can be used to specify a source IP address in all syslog packets sent from the device. The following syslog filter module example demonstrates the use of show CLI commands (show running-config and show ip interface in this case) within a filter module to add the source IP address to syslog messages. The script looks for the local namespace variable “source_ip::init” first. If the variable is not defined in the first syslog message processed, the filter will run the show commands and use regular expressions to get the source interface and then its IP address.

Note that in this script, the show commands are run only once. If the source interface or its IP address were to be changed, the filter would have to be reinitialized to pick up the new information. (You could have the show commands run on every syslog message, but this would not scale well.)

#  ===================================================================
#  Embedded Syslog Manager                           ||        ||
#                                                    ||        ||
#  Source IP Module                                 ||||      ||||
#                                               ..:||||||:..:||||||:..
#                                             ------------------------
#                                              C i s c o  S y s t e m s 
#   ===================================================================
# Usage: Adds Logging Source Interface IP address to all messages.
#
# Namespace:source_ip
#
#  ======================= End User Setup ==============================
namespace eval ::source_ip {
    if { [info exists init] == 0 } {
       if { [catch {regexp {^logging source-interface (.*$)} [exec show
run | inc logging source-interface] match source_int}]} {
           set suffix "No source interface specified"
       } elseif { [catch {regexp {Internet address is (.*)/.*$} [exec
show ip int $source_int | inc Internet] match ip_addr}]} {
           set suffix "No IP address configured for source interface"
       } else {
           set suffix $ip_addr
       }
       set init 1
    }
 
    if { [string length $::orig_msg] == 0} {
      return ""
    }
    return "$::orig_msg - $suffix"
} ;# end namespace source_ip