Improve logs: apply structure for monitoring

* Add ability to suppress logs
* Refactor variable names

odroid-xu3-fan-control.sh

@@ -3,7 +3,10 @@
 # Loud fan control script to lower speed of fun based on current
 # max temperature of any cpu
 #
-# works only on XU3 Lite with Ubuntu 14.04.1
+# See README.md for details.
+
+#set to false to suppress logs
+DEBUG=true
 
 # Make sure only root can run our script
 if (( $EUID != 0 )); then
@@ -17,11 +20,12 @@ TEMPERATURE_FILE="/sys/devices/10060000.tmu/temp"
 FAN_MODE_FILE="/sys/devices/odroid_fan.14/fan_mode"
 FAN_SPEED_FILE="/sys/devices/odroid_fan.14/pwm_duty"
 TEST_EVERY=3 #seconds
-speed_fan_to_default=80
+new_fan_speed_default=80
+LOGGER_NAME=odroid-xu3-fan-control
 
 #make sure after quiting script fan goes to auto control
 function cleanup {
-  logger -t $0 "fan-control quiting. Setting fan to auto"
+  ${DEBUG} && logger -t $LOGGER_NAME "event: quit; temp: auto"
   echo 1 > ${FAN_MODE_FILE}
 }
 trap cleanup EXIT
@@ -36,28 +40,30 @@ do
   echo 0 > ${FAN_MODE_FILE} #to be sure we can manage fan
 
   current_max_temp=`cat ${TEMPERATURE_FILE} | cut -d: -f2 | sort -nr | head -1`
-  logger -t $0 "current_max_temp: ${current_max_temp}"
+  ${DEBUG} && logger -t $LOGGER_NAME "event: read_max; temp: ${current_max_temp}"
 
+  new_fan_speed=0
   if (( ${current_max_temp} >= 75000 )); then
-    speed_fan_to=255
+    new_fan_speed=255
   elif (( ${current_max_temp} >= 70000 )); then
-    speed_fan_to=200
+    new_fan_speed=200
   elif (( ${current_max_temp} >= 68000 )); then
-    speed_fan_to=130
+    new_fan_speed=130
   elif (( ${current_max_temp} >= 66000 )); then
-    speed_fan_to=70 
+    new_fan_speed=70 
   elif (( ${current_max_temp} >= 63000 )); then
-    speed_fan_to=65 
+    new_fan_speed=65 
   elif (( ${current_max_temp} >= 60000 )); then
-    speed_fan_to=60
+    new_fan_speed=60
   elif (( ${current_max_temp} >= 58000 )); then
-    speed_fan_to=50
+    new_fan_speed=50
   elif (( ${current_max_temp} >= 55000 )); then
-    speed_fan_to=30
+    new_fan_speed=30
   else
-    speed_fan_to=2
+    new_fan_speed=2
   fi
-  echo ${speed_fan_to} > ${FAN_SPEED_FILE}
+  ${DEBUG} && logger -t $LOGGER_NAME "event: adjust; speed: ${new_fan_speed}"
+  echo ${new_fan_speed} > ${FAN_SPEED_FILE}
 
   sleep ${TEST_EVERY}
 done