utils.py

#!/usr/bin/env python3
"""
Various utilities for use with AWS batch.
"""


import boto3

def get_latest_ecs_ami():
    """Get the ID of the latest official AWS AMI in this region that is
       suitable for use with ECS and AWS Batch."""
    ec2 = boto3.client("ec2", region_name="us-west-2")
    filters = [dict(Name='manifest-location', Values=['amazon/amzn-ami-*-amazon-ecs-optimized'])]
    got = ec2.describe_images(Filters=filters)
    sorted_amis = sorted(got['Images'], key=lambda k: k['CreationDate'])
    return sorted_amis[-1]['ImageId']

def get_latest_scratch_ami(get_all=False):
    """
    Get the ID of the latest AMI created by SciComp which is based on
    official ECS-compliant AMIs but has 1TB of scratch space on it.
    These AMIs will always be owned by the SciComp account and
    have the Type: FredHutchBatchAMI tag. (However, tags are not
    used in this function because they are only visible to the account
    that created the AMI, so instead we use the image name.)
    """
    ec2 = boto3.client("ec2", region_name="us-west-2")
    scicomp_account_number = '344850189907'
    filters = [{'Name': 'owner-id', 'Values': [scicomp_account_number]},
               {'Name': 'name',
                'Values': ['ECS image with 1TB non-encrypted scratch at /scratch. Created at *']}]
    got = ec2.describe_images(Filters=filters)
    sorted_amis = sorted(got['Images'], key=lambda k: k['CreationDate'])
    if get_all:
        return sorted_amis
    return sorted_amis[-1]['ImageId']


def get_latest_docker_image():
    """
    Returns the full name (including tag) of the latest
    supported Docker image supported by Fred Hutch for
    AWS Batch jobs. It should be an image that has
    as its ENTRYPOINT the fetch-and-run script.

    For now we are just hardcoding the name as there is
    only one image and (as of yet) no programmatic
    way to determine which is the most recent.
    """
    return "fredhutch/ls2:picard.1"

# just for testing
if __name__ == '__main__':
    print(get_latest_scratch_ami())