From d98d9643a8ce1acb36bce39af04154634fd7a61e Mon Sep 17 00:00:00 2001
From: Daniel Jakots <djakots@evolix.ca>
Date: Fri, 17 Feb 2017 10:18:14 -0500
Subject: [PATCH] implement a check to see if the script is already running

---
 bgpd-check-peers.sh | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/bgpd-check-peers.sh b/bgpd-check-peers.sh
index 0fb4efd..a5c6f18 100644
--- a/bgpd-check-peers.sh
+++ b/bgpd-check-peers.sh
@@ -15,9 +15,20 @@ PATH=$HOME/bin:/bin:/sbin:/usr/bin:/usr/sbin:/usr/local/bin:/usr/local/sbin:.
 
 _MAILTO="noc@example.com"
 _TMPDIR=/tmp/check-bgp
+_HOSTNAME=$(hostname)
 
 mkdir -p "${_TMPDIR}"
 
+# Don't try to run if it's already running
+if [ -e "${_PIDFILE}" ]; then
+    echo "$(date)" >> "${_TMPDIR}"/log
+    # for debug purpose
+    echo "bgpd was already running" | mail -s "[BGP] ${_HOSTNAME}" foo@example.com
+    exit 1
+else
+    echo $$ >> "${_PIDFILE}"
+fi
+
 if [[ -f "${_TMPDIR}"/bgp-status ]] ; then
     mv "${_TMPDIR}"/bgp-status "${_TMPDIR}"/bgp-status.old
 else
@@ -45,7 +56,8 @@ done <"${_TMPDIR}"/peers-list
 different=$(diff -q "${_TMPDIR}"/bgp-status.old "${_TMPDIR}"/bgp-status)
 
 if ! [[ -n "${different}" ]] ; then
-	exit 0
+    rm -f "${_PIDFILE}"
+    exit 0
 fi
 
 # It changed so we're going to send a mail
@@ -77,11 +89,10 @@ if [[ -f "${_TMPMAILDIR}"/bodynok ]] ; then
     cat "${_TMPMAILDIR}"/bodynok >> "${_TMPMAILDIR}"/body
 fi
 
-_HOSTNAME=$(hostname)
-
 cat "${_TMPMAILDIR}"/body | mail -s "[BGP] ${_HOSTNAME} - State change" "${_MAILTO}"
 
 # cleaning
 if [[ -d  "${_TMPMAILDIR}" ]] ; then
     rm -rf  "${_TMPMAILDIR}"
 fi
+rm -f "${_PIDFILE}"