Creates mapping in YAML for AWS CloudFormation

cf_mapping_helper.py

# searches all regions and creates a CloudFormation "Mappings" 
# YAML template with;
# - AMI IDs
# - zones for regions
#
# Usage:
# modify images dictionary
# structure is like below;
#
# 'alias': {
#   'name':'put image name that you find on AWS Console'
#   'owner-id' | 'owner-alias':'put owner-id if alias is not available'    
# }
# 
# You can find image name and owner-id or owner-alias by going to console
# and looking at one of the regions. Once you find these for one region
# this program can populate rest for you.
#
# You can also use AWS CLI to collect information about AMIs as seen below.
# $ aws ec2 describe-images --image-ids ami-0932686c ami-c06d48a5 --region us-east-2
#

import boto3

images = {
    'MasterAMI': {
        'name':'RHEL-7.3_HVM_GA-20161026-x86_64-1-Hourly2-GP2',
        'owner-id':'309956199498'},
    'EnterpriseAMI': {
        'name':'RHEL-7.3_HVM_GA-20161026-x86_64-1-Hourly2-GP2',
        'owner-id':'309956199498'},        
    'MinionLin': {
        'name':'amzn-ami-hvm-2016.09.1.20170119-x86_64-gp2',
        'owner-alias':'amazon'},
    'MinionWin':{
        'name':'Windows_Server-2012-R2_RTM-English-64Bit-Base-2017.05.10',
        'owner-alias':'amazon'}
    }

AZ_PREFIX = 'TestAZ'

client = boto3.client('ec2')
response = client.describe_regions()
regions = [region['RegionName'] for region in response['Regions']]

print('Mappings:')
print('  RegionMap:')
for region in regions:
    print('    {}:'.format(region))
    client = boto3.client('ec2', region_name=region)
    for alias, image in images.items():
        filters = []
        filters.append(
            {
                'Name': 'name',
                'Values': [
                    image['name']
                ]
            })
        if 'owner-id' in image:
            filters.append(
                {
                    'Name': 'owner-id',
                    'Values': [
                        image['owner-id']
                    ]
                })
        if 'owner-alias' in image:
            filters.append(
                {
                    'Name': 'owner-alias',
                    'Values': [
                        image['owner-alias']
                    ]
                })             
        response = client.describe_images(
            DryRun=False,
            Filters=filters
        )        
        for image in response['Images']:
            print('      {}: {}'.format(alias, image['ImageId']))

    response = client.describe_availability_zones()
    zones = [zone['ZoneName'] for zone in response['AvailabilityZones'] if zone['State'] == 'available' ]
    for i in range(len(zones)):
        print('      {}{}: {}'.format(AZ_PREFIX, i, zones[i]))

Sample output:

Mappings:
  RegionMap:
    ap-south-1:
      MasterAMI: ami-7c9bef13
      EnterpriseAMI: ami-7c9bef13
      MinionLin: ami-f9daac96
      MinionWin: ami-67047908
      TestAz0: ap-south-1a
      TestAz1: ap-south-1b
    eu-west-2:
      MasterAMI: ami-9c363cf8
      EnterpriseAMI: ami-9c363cf8
      MinionLin: ami-f1949e95
      MinionWin: ami-07455263
      TestAz0: eu-west-2a
      TestAz1: eu-west-2b
   ....
     ....