Custom Cloudwatch Plugins CW_MemoryUsage Part-3

The following plugin pushes the memory consumption of the vm to the cloudwatch which you can use to set the alarms and also can use for the autoscaling or taking actions when combined with the events.

#!/bin/bash
#
#  About                : Check used memory in percentage
#
#  Name                 : cw_memory.sh


DIR=$(dirname $0);
PLUGIN_NAME='cw_memory';

# Include configuration file
source ${DIR}/../conf/plugin.conf;


#Get Current Instance ID
INSTANCE_ID=(`wget -q -O - http://169.254.169.254/latest/meta-data/instance-id`);
#Get Hostname
HOST_ID=(`wget -q -O - http://169.254.169.254/latest/meta-data/hostname`);

# Help
usage() {
        echo "Usage: $0 [-n ] [-d ] [-m ] " 1>&2;
        exit 1;
}

# Logger
logger(){

 SEVERITY=$1;
 MESSAGE=$2;
 DATE=`date +"[%Y-%b-%d %H:%M:%S.%3N]"`;

 echo -e "${DATE} [${SEVERITY}] [${PLUGIN_NAME}] [${INSTANCE_ID}] [${HOST_ID}] ${MESSAGE}" >> ${DIR}/../logs/appcwmon.log;

}

# Process Arguments

if [ $# -eq 0 ]; then
        # When no argument is passed
        logger ERROR "Invalid arguments passed";
        usage;
fi


while getopts ":n:d:m:a:" o; do
    case "${o}" in
        n)
            NAMESPACE=${OPTARG}
            if [ -z "${NAMESPACE}" ]; then
                logger ERROR "Invalid Namespace passed";
                usage;
            fi
            ;;
        d)
            DIMENSION=${OPTARG};
            DNAME=${DIMENSION%=*};
            DVALUE=${DIMENSION#*=};

            if [ -z "${DIMENSION}" ] || [ -z "${DNAME}" ] || [ "${DNAME}" == "${DVALUE}" ]; then
                logger ERROR "Invalid dimension passed <${DIMENSION}>";
                usage;
            fi

            # If Dimension name is 'InstanceId' then Value is not required to be passed
            if [ "${DNAME}" != 'InstanceId' ] && [ -z "${DVALUE}" ]; then
                logger ERROR "Invalid dimension passed <${DIMENSION}>";
                usage;
            fi
            ;;
        m)
            METRICS=${OPTARG}
            if [ -z "${METRICS}" ]; then
                logger ERROR "Invalid metrics passed <${METRICS}>";
                usage;
            fi
            ;;
        *)
            usage
            ;;
    esac
done
shift $((OPTIND-1))

# Input Validation
if [ -z "${NAMESPACE}" ] || [ -z "${DNAME}" ] || [ -z "$METRICS" ]; then
    logger ERROR "Invalid arguments passed";
    usage
fi


##########################################################
##########################################################


# If "INSTANCE_ID" is passed as Dimension, then use actual AWS Instanec ID as Dimension
if [ "${DNAME}" == "InstanceId" ]; then
        DVALUE=${INSTANCE_ID};
fi

##########################

UNIT="Percent"

# Get Total Memory
#MEM_TOTAL=$(free -m | grep 'Mem' | awk '{print $2}' 2>&1);
MEM_TOTAL=$(awk '/^MemTotal/ {print $2}' /proc/meminfo 2>&1);

if [ "$?" -ne "0" ]; then
        logger ERROR "${NAMESPACE} ${METRICS} ${DNAME}=${DVALUE} | value=NULL | ${MEM_TOTAL}";
        exit 1;
fi;

MEM_FREE=$(awk '/^MemFree/ {print $2}' /proc/meminfo 2>&1);

if [ "$?" -ne "0" ]; then
        logger ERROR "${NAMESPACE} ${METRICS} ${DNAME}=${DVALUE} | value=NULL | ${MEM_FREE}";
        exit 1;
fi;

MEM_BUFFER=$(awk '/^Buffers/ {print $2}' /proc/meminfo 2>&1);

if [ "$?" -ne "0" ]; then
        logger ERROR "${NAMESPACE} ${METRICS} ${DNAME}=${DVALUE} | value=NULL | ${MEM_BUFFER}";
        exit 1;
fi;

MEM_CACHED=$(awk '/^Cached/ {print $2}' /proc/meminfo 2>&1);

if [ "$?" -ne "0" ]; then
        logger ERROR "${NAMESPACE} ${METRICS} ${DNAME}=${DVALUE} | value=NULL | ${MEM_CACHED}";
        exit 1;
fi;

# Memory Used (In Percentage)
let "VALUE=((MEM_TOTAL - (MEM_FREE + MEM_BUFFER + MEM_CACHED))*100)/MEM_TOTAL";

if [ "$?" -ne "0" ]; then
        logger ERROR "${NAMESPACE} ${METRICS} ${DNAME}=${DVALUE} | value=NULL | ${VALUE}";
        exit 1;
fi;

## Pushing Cloudwatch Metric data
OUTPUT=$(/usr/local/bin/aws cloudwatch put-metric-data --namespace ${NAMESPACE} --metric-name ${METRICS} --dimensions ${DNAME}=${DVALUE} --value ${VALUE} --unit ${UNIT} 2>&1);

if [ "$?" -ne "0" ]; then
        logger ERROR "${NAMESPACE} ${METRICS} ${DNAME}=${DVALUE} | value=${VALUE} unit=${UNIT} | ${OUTPUT}";
        exit 1;
fi;

logger INFO "${NAMESPACE} ${METRICS} ${DNAME}=${DVALUE} | value=${VALUE} unit=${UNIT}";

# Success
exit 0;