variable change, reduce noise

- s/cntFailures/cntNotify/; 
- emit status only on state transitions, can get noisy if testing once a minute in crontab
  - uses file names to track node status

path-loss.sh

@@ -17,27 +17,52 @@ nodes=( \
   )
 
 # local variables
-cntFailures=0
-status=""
+cntNotify=0
+status="|"
 tmpLog=$(mktemp)
 tmpPing=$(mktemp)
 
 # preload output
 date > ${tmpLog}
 
-# loop through nodes nd test
+# loop through nodes and test
 for node in  ${!nodes[*]}; do
   echo -e ${txtSeparator} >> ${tmpLog};
   echo "checking node ${nodes[${node}]}:" >> ${tmpLog};
   echo "" >> ${tmpLog}
+
   ping -W 1 -c ${nAttempts} ${node} > ${tmpPing}
   cat ${tmpPing} >> ${tmpLog}
+
   value=$(grep transmitted ${tmpPing} | cut -d ' ' -f 4)
-  if [[ nTrigger -ge value ]]; then
-    ((cntFailures++));
-    mtr -w -b --report ${node} >> ${tmpLog};
-    status="${status} ${nodes[${node}]}"
+  if [[ nTrigger -ge value ]]; then flagNxt="dn"
+  else flagNxt="up"; fi
+
+  flagPrv="na"
+
+  if [[ -f /tmp/pl.dn.${node} ]]; then
+    flagPrv="dn"
+    if test "up" = "${flagNxt}"; then
+      rm /tmp/pl.dn.${node}
     fi
+  fi
+
+  if [[ -f /tmp/pl.up.${node} ]]; then
+    flagPrv="up"
+    if test "dn" = "${flagNxt}"; then
+      rm /tmp/pl.up.${node}
+    fi
+  fi
+
+  if test "${flagPrv}" != "${flagNxt}"; then
+    touch /tmp/pl.${flagNxt}.${node}
+    ((cntNotify++));
+    mtr -w -b --report ${node} >> ${tmpLog};
+    status="${status} ${nodes[${node}]} ${flagPrv}>${flagNxt} |"
+    echo "" >> ${tmpLog}
+    echo "Above State Change: ${flagPrv}>${flagNxt}" >> ${tmpLog}
+  fi
+
 done
 
 # footer
@@ -45,7 +70,7 @@ echo -e ${txtSeparator} >> ${tmpLog};
 date >> ${tmpLog}
 
 # notify on failure
-if [[ cntFailures -gt 0 ]]; then
+if [[ cntNotify -gt 0 ]]; then
   cat ${tmpLog} | mail -s "${txtSubject}:${status}" ${txtEmail};
 fi