aten_pdu: Add noop mode to mqtt publish script

roles/aten_pdu/files/aten-mqtt-publish.sh

@@ -5,6 +5,12 @@ umask 077
 
 community="public"
 
+if [ "${1:-}" = "-n" ]; then
+    _noop=true
+else
+    _noop=false
+fi
+
 mqtt_send() {
     topic="$1"
     value="$2"
@@ -48,7 +54,11 @@ do
 	for key in Current Power Voltage ; do
             topic="home/${location}/${device}/$(echo "$key" | tr '[:upper:]' '[:lower:]')"
 	    value="$(snmp_get "$name" "ATEN-PE-CFG::outlet${key}.${port}")"
-            mqtt_send "$topic" "$value"
+            if $_noop ; then
+                echo "${topic} -> ${value}"
+            else
+                mqtt_send "$topic" "$value"
+            fi
         done
     done
 done