#!/usr/bin/python
import boto.ec2.cloudwatch
import sys
import datetime
 
try:
    metName = sys.argv[1]
    funcName = sys.argv[2]
    dimSpace = sys.argv[3]
    region = sys.argv[4]
    accessKey = sys.argv[5]
    secretKey = sys.argv[6]
 
except:
    print "Usage: GetFromCloudwatch.py MetricName Function Dimension Region AWS_ACCESS_KEY AWS_SECRET_ACCESS_KEY"
    print "Example: GetFromCloudwatch.py FreeableMemory Average \"CacheClusterId=ElsticCacheName\" us-east-1 ACCESS_KEY SECRET_ACCESS_KEY"
    print "         GetFromCloudwatch.py CPUUtilization Average \"DBInstanceIdentifier=RDSName\" us-east-1 ACCESS_KEY SECRET_ACCESS_KEY"
    print "         GetFromCloudwatch.py ApproximateNumberOfMessagesVisible Average \"QueueName=SQSName\" us-east-1 ACCESS_KEY SECRET_ACCESS_KEY"
    sys.exit(1)
 
dim = {}
firstSplit = dimSpace.split(',')
for word in firstSplit:
    secondSplit = word.split('=')
    dim[secondSplit[0]] = secondSplit[1]
 
regions = boto.ec2.cloudwatch.regions()
 
reg = ''
for r in regions:
    if region == r.name:
        reg = r
 
c = boto.ec2.cloudwatch.CloudWatchConnection(aws_access_key_id=accessKey, aws_secret_access_key=secretKey, region=reg)
metrics = c.list_metrics(dimensions=dim)
 
end = datetime.datetime.utcnow()
start = end - datetime.timedelta(minutes=15)
 
dataPoints = [];
for met in metrics:
    if met.name == metName:
        dataPoints = met.query(start, end, funcName)
 
if len(dataPoints) > 0:
    max = datetime.datetime.utcnow() - datetime.timedelta(hours=1)
    index = 0
    for i in range(0,len(dataPoints)):
        if max < dataPoints[i][u'Timestamp']:
            max = dataPoints[i][u'Timestamp']
            index = i
    for key in dataPoints[index].keys():
        if funcName in key:
            value = dataPoints[index][key]
    print value
else:
    print 'Error! No response from Amazon.'
    sys.exit(2)