Django settings for ECS (awsvpc network mode)

ecs.py

"""
AWS ECS django settings
"""

import requests
from .settings import *  # may look different for your project


def get_ecs_task_ips():
    """
    Retrieve the internal ip address(es) for task, if running with AWS ECS and awsvpc networking mode
    Used to get ips to add to ALLOWED_HOSTS setting, for load balancer health checks
    See https://docs.aws.amazon.com/AmazonECS/latest/developerguide/task-metadata-endpoint.html
    Uses V2 endpoint: http://169.254.170.2/v2/metadata (v3 not yet available on fargate)
    :return: list of internal ip addresses
    """
    ip_addresses = []
    try:
        r = requests.get("http://169.254.170.2/v2/metadata", timeout=0.01)
    except requests.exceptions.RequestException:
        return []
    if r.ok:
        task_metadata = r.json()
        for container in task_metadata['Containers']:
            for network in container['Networks']:
                if network['NetworkMode'] == 'awsvpc':
                    ip_addresses.extend(network['IPv4Addresses'])
    return list(set(ip_addresses))


# Add ip(s) to ALLOWED HOSTS django setting
ALLOWED_HOSTS += ecs_task_ips()