#!/bin/bash

# Nick's bash script to create CPU gauges from AWS CloudWatch
# Source: http://www.linickx.com/archives/3153/amazon-cloudwatch-cpu-gauge

# Setup some Time Variables
NowMins=`date "+%M"`
NowHrs=`date "+%H"`
Today=`date "+%Y-%m-%d"`

# The last five minute reading is avilable every ten mintues
FiveMinsAgo=$(($NowMins - 10))

# If our calcualtion is a negative number correct hours and minutes
if [ $FiveMinsAgo -lt 0 ]
then
	FiveMinsAgo=$(($FiveMinsAgo + 60))
	NowHrs=$(($NowHrs - 1))
fi

# Re-Apply leading zero that gets dropped by calculations
if [ $FiveMinsAgo -lt 10 ]
then
        FiveMinsAgo="0"$FiveMinsAgo
fi

#Formate Start Time for API Tools
StartTime=$Today"T"$NowHrs":"$FiveMinsAgo":00.000Z"

# Get Results from API Tools
Result=`mon-get-stats CPUUtilization --namespace "AWS/EC2" --statistics "Maximum"  --dimensions "InstanceId=i-123456" --start-time $StartTime `

Percent=`echo $Result | awk '{print $3}'`

Chart="https://chart.googleapis.com/chart?chs=200x125&cht=gom&chd=t:"$Percent"&chl="$Percent"%&chco=00AA0066,FF804066,AA000066&chf=bg,s,FFFFFF00"

curl $Chart -o cpu.png