#!/usr/bin/python3.4

from docker import Client
from docker.errors import APIError
from string import Template
import json
import signal
import os
from socket import getaddrinfo
import logging


def get_if_available(dict, key, defValue):
    if key in dict:
        return dict[key]
    else:
        return defValue


def analyse_proxy_data(data):
    """Extracts the data for the proxy configuration (envrionment variable
        'PROXY_DATA' and converts it to a dictionary."""
    proxy_data = {}
    for proxy_var in data.split(','):
        t = proxy_var.split(":", 1)
        proxy_data[t[0]] = t[1]
    return proxy_data


def analyse_env_vars(inspect_data):
    """Extracts the environment variables from the given result of an 'inspect
        container' call."""
    env_data = {}
    counter = 0
    if not 'Env' in inspect_data['Config'] or inspect_data['Config']['Env'] is None:
        return env_data
    for env_var in inspect_data['Config']['Env']:
        t = env_var.split("=")
        key = t[0]
        value = t[1]
        if key == 'PROXY_DATA':
            if key in env_data:
                key = "{key}{postfix}".format(key=key, postfix=counter)
                counter+=1
            env_data[key] = value
    return env_data


def handle_container(docker_client, id):
    """This function take a container's id and collects all data required
        to create a proper proxy configuration. The configuration is then
        written to the directory of temporary nginx files"""
    inspect_data = docker_client.inspect_container(id)
    env_vars = analyse_env_vars(inspect_data)
    names = []
    for key in env_vars:
        value = env_vars[key]
        proxy_data = analyse_proxy_data(value)
        names += get_if_available(proxy_data, 'server_names', '').split(';')
    logging.info('list of domains on: %s', str(names))
    return names


def get_resolving_domains_from_containers(docker_client):
    container_ids = docker_client.containers(quiet=True)

    logging.info('list of containers: %s', str(container_ids))

    domains = []
    for container_id in container_ids:
        domains.extend(handle_container(docker_client, container_id['Id']))

    logging.info('list of activated domains on containers: %s', str(domains))

    resolved_domains = []
    for domain in domains:
        try:
            getaddrinfo(domain, None)
            resolved_domains.append(domain)
        except Exception:
            pass

    logging.info('list of resolved domains on containers: %s', str(resolved_domains))

    return resolved_domains


if __name__ == '__main__':
    client = Client(base_url='unix://var/run/docker.sock', version='1.15')

    resolved_domains = get_resolving_domains_from_containers(client)

    print(str(resolved_domains))