Added Docker healthcheck to README.md

Dockerfile

@@ -7,12 +7,15 @@ RUN apt-get update
 RUN apt-get install ipmitool -y
 
 ADD functions.sh /app/functions.sh
+ADD healthcheck.sh /app/healthcheck.sh
 ADD Dell_iDRAC_fan_controller.sh /app/Dell_iDRAC_fan_controller.sh
 
-RUN chmod 0777 /app/functions.sh /app/Dell_iDRAC_fan_controller.sh
+RUN chmod 0777 /app/functions.sh /app/healthcheck.sh /app/Dell_iDRAC_fan_controller.sh
 
 WORKDIR /app
 
+HEALTHCHECK --interval=30s --timeout=30s --start-period=5s --retries=3 CMD [ "/app/healthcheck.sh" ]
+
 # you should override these default values when running. See README.md
 #ENV IDRAC_HOST 192.168.1.100
 ENV IDRAC_HOST local

healthcheck.sh

@@ -0,0 +1,24 @@
+#!/bin/bash
+
+# Enable strict bash mode to stop the script if an uninitialized variable is used, if a command fails, or if a command with a pipe fails
+# Not working in some setups : https://github.com/tigerblue77/Dell_iDRAC_fan_controller/issues/48
+# set -euo pipefail
+
+source functions.sh
+
+# Check if the iDRAC host is set to 'local' or not then set the IDRAC_LOGIN_STRING accordingly
+if [[ $IDRAC_HOST == "local" ]]
+then
+  # Check that the Docker host IPMI device (the iDRAC) has been exposed to the Docker container
+  if [ ! -e "/dev/ipmi0" ] && [ ! -e "/dev/ipmi/0" ] && [ ! -e "/dev/ipmidev/0" ]; then
+    echo "/!\ Could not open device at /dev/ipmi0 or /dev/ipmi/0 or /dev/ipmidev/0, check that you added the device to your Docker container or stop using local mode. Exiting." >&2
+    exit 1
+  fi
+  IDRAC_LOGIN_STRING='open'
+else
+  echo "iDRAC/IPMI username: $IDRAC_USERNAME"
+  echo "iDRAC/IPMI password: $IDRAC_PASSWORD"
+  IDRAC_LOGIN_STRING="lanplus -H $IDRAC_HOST -U $IDRAC_USERNAME -P $IDRAC_PASSWORD"
+fi
+
+ipmitool -I $IDRAC_LOGIN_STRING sdr type temperature