building_manager.py

#!/usr/bin/env python3
""" Python module to assist creating and maintaining docker openHab stacks."""
import crypt
import logging
import os
from shutil import copy2
from subprocess import PIPE, run

import bcrypt
import docker
from PyInquirer import prompt
from ruamel.yaml import YAML

# Configure YAML
yaml = YAML()
yaml.indent(mapping=4, sequence=4, offset=2)

# Log level during development is info
logging.basicConfig(level=logging.WARNING)

# Directories for config generation
CUSTOM_DIR = 'custom_configs'
TEMPLATE_DIR = 'template_configs'
COMPOSE_NAME = 'docker-stack.yml'
SKELETON_NAME = 'docker-skeleton.yml'
TEMPLATES_NAME = 'docker-templates.yml'
CONFIG_DIRS = ['mosquitto', 'nodered', 'ssh', 'traefik', 'volumerize']
TEMPLATE_FILES = [
    'mosquitto/mosquitto.conf', 'nodered/nodered_package.json',
    'nodered/nodered_settings.js', 'ssh/sshd_config', 'traefik/traefik.toml'
]
EDIT_FILES = {
    "mosquitto_passwords": "mosquitto/mosquitto_passwords",
    "sftp_users": "ssh/sftp_users.conf",
    "traefik_users": "traefik/traefik_users",
    "id_rsa": "ssh/id_rsa",
    "host_key": "ssh/ssh_host_ed25519_key",
    "known_hosts": "ssh/known_hosts",
    "backup_config": "volumerize/backup_config.json"
}
CONSTRAINTS = {"building": "node.labels.building"}
SERVICES = {
    "sftp": "sftp_X",
    "openhab": "openhab_X",
    "nodered": "nodered_X",
    "mqtt": "mqtt_X"
}

# Default Swarm port
SWARM_PORT = 2377
# UID for admin
UID = 9001
# Username for admin
ADMIN_USER = 'ohadmin'

# ******************************
# Compose file functions {{{
# ******************************


def generate_initial_compose(base_dir):
    """Creates the initial compose using the skeleton

    :base_dir: Folder to place configuration files into
    """
    base_path = base_dir + '/' + CUSTOM_DIR
    template_path = base_dir + '/' + TEMPLATE_DIR
    # compose file
    compose = base_path + '/' + COMPOSE_NAME
    # skeleton file
    skeleton = template_path + '/' + SKELETON_NAME

    with open(skeleton, 'r') as skeleton_f, open(compose, 'w+') as compose_f:
        init_content = yaml.load(skeleton_f)
        yaml.dump(init_content, compose_f)


def add_sftp_service(base_dir, hostname, number=0):
    """Generates an sftp entry and adds it to the compose file

    :base_dir: base directory for configuration files
    :hostname: names of host that the services is added to
    :number: increment of exposed port to prevent overlaps
    """
    base_path = base_dir + '/' + CUSTOM_DIR
    # compose file
    compose_path = base_path + '/' + COMPOSE_NAME
    # service name
    service_name = f'sftp_{hostname}'
    # template
    template = get_service_template(base_dir, SERVICES['sftp'])
    # only label contraint is building
    template['deploy']['placement']['constraints'][0] = (
        f"{CONSTRAINTS['building']} == {hostname}")
    template['ports'] = [f'{2222 + number}:22']

    add_or_update_compose_service(compose_path, service_name, template)


def add_openhab_service(base_dir, hostname):
    """Generates an openhab entry and adds it to the compose file

    :base_dir: base directory for configuration files
    :hostname: names of host that the services is added to
    """
    base_path = base_dir + '/' + CUSTOM_DIR
    # compose file
    compose_path = base_path + '/' + COMPOSE_NAME
    # service name
    service_name = f'openhab_{hostname}'
    # template
    template = get_service_template(base_dir, SERVICES['openhab'])
    # only label contraint is building
    template['deploy']['placement']['constraints'][0] = (
        f"{CONSTRAINTS['building']} == {hostname}")
    # include in backups of this building
    template['deploy']['labels'].append(f'backup={hostname}')
    # traefik backend
    template['deploy']['labels'].append(f'traefik.backend={service_name}')
    # traefik frontend domain->openhab
    template['deploy']['labels'].extend(
        generate_traefik_host_labels(hostname, segment='main'))
    # traefik frontend subdomain openhab_hostname.* -> openhab
    template['deploy']['labels'].append(
        f'traefik.sub.frontend.rule=HostRegexp:'
        f'{service_name}.{{domain:[a-zA-z0-9-]+}}')
    template['deploy']['labels'].append('traefik.sub.frontend.priority=2')

    add_or_update_compose_service(compose_path, service_name, template)


def add_nodered_service(base_dir, hostname):
    """Generates an nodered entry and adds it to the compose file

    :base_dir: base directory for configuration files
    :hostname: names of host that the services is added to
    """
    base_path = base_dir + '/' + CUSTOM_DIR
    # compose file
    compose_path = base_path + '/' + COMPOSE_NAME
    # service name
    service_name = f'nodered_{hostname}'
    # template
    template = get_service_template(base_dir, SERVICES['nodered'])
    # only label contraint is building
    template['deploy']['placement']['constraints'][0] = (
        f"{CONSTRAINTS['building']} == {hostname}")
    template['deploy']['labels'].append(f'traefik.backend={service_name}')
    template['deploy']['labels'].append(f'backup={hostname}')
    template['deploy']['labels'].extend(
        generate_traefik_path_labels(service_name, segment='main'))

    add_or_update_compose_service(compose_path, service_name, template)


def add_mqtt_service(base_dir, hostname, number=0):
    """Generates an mqtt entry and adds it to the compose file

    :base_dir: base directory for configuration files
    :hostname: names of host that the services is added to
    :number: increment of exposed port to prevent overlaps
    """
    base_path = base_dir + '/' + CUSTOM_DIR
    # compose file
    compose_path = base_path + '/' + COMPOSE_NAME
    # service name
    service_name = f'mqtt_{hostname}'
    # template
    template = get_service_template(base_dir, SERVICES['mqtt'])
    # only label contraint is building
    template['deploy']['placement']['constraints'][0] = (
        f"{CONSTRAINTS['building']} == {hostname}")
    # ports incremented by number of services
    template['ports'] = [f'{1883 + number}:1883', f'{9001 + number}:9001']

    add_or_update_compose_service(compose_path, service_name, template)


# Helper functions
def get_service_template(base_dir, service_name):
    """Gets a service template entry from the template yaml

    :return: yaml entry of a service
    """
    template_path = base_dir + '/' + TEMPLATE_DIR
    templates = template_path + '/' + TEMPLATES_NAME

    with open(templates, 'r') as templates_file:
        template_content = yaml.load(templates_file)

    return template_content['services'][service_name]


def generate_traefik_host_labels(hostname, segment=None, priority=1):
    """Generates a traefik path url with necessary redirects

    :hostname: Hostname that gets assigned by the label
    :segment: Optional traefik segment when using multiple rules
    :priority: Priority of frontend rule
    :returns: list of labels for traefik
    """
    label_list = []
    # check segment
    segment = f'.{segment}' if segment is not None else ''
    # fill list
    label_list.append(
        f'traefik{segment}.frontend.rule=HostRegexp:{{domain:{hostname}}}')
    label_list.append(f'traefik{segment}.frontend.priority={priority}')
    return label_list


def generate_traefik_path_labels(url_path, segment=None, priority=2):
    """Generates a traefik path url with necessary redirects

    :url_path: path that should be used for the site
    :segment: Optional traefik segment when using multiple rules
    :priority: Priority of frontend rule
    :returns: list of labels for traefik
    """
    label_list = []
    # check segment
    segment = f'.{segment}' if segment is not None else ''
    # fill list
    label_list.append(f'traefik{segment}.frontend.priority={priority}')
    label_list.append(
        f'traefik{segment}.frontend.redirect.regex=^(.*)/{url_path}$$')
    label_list.append(
        f'traefik{segment}.frontend.redirect.replacement=$$1/{url_path}/')
    label_list.append(
        f'traefik{segment}.frontend.rule=PathPrefix:/{url_path};'
        f'ReplacePathRegex:^/{url_path}/(.*) /$$1')
    return label_list


def add_or_update_compose_service(compose_path, service_name, service_content):
    """Adds or replaces a service in a compose file

    :compose_path: path of the compose file to change
    :service_name: name of the service to add/replace
    :service_content: service definition to add
    """
    with open(compose_path, 'r+') as compose_f:
        # load compose file
        compose = yaml.load(compose_f)
        # add / update service with template
        compose['services'][service_name] = service_content
        # write content starting from first line
        compose_f.seek(0)
        # write new compose content
        yaml.dump(compose, compose_f)
        # reduce file to new size
        compose_f.truncate()
# }}}


# ******************************
# Config file functions {{{
# ******************************
def generate_config_folders(base_dir):
    """Generate folders for configuration files

    :base_dir: Path to add folders to
    """
    base_path = base_dir + '/' + CUSTOM_DIR
    if not os.path.exists(base_dir):
        os.makedirs(base_dir)

    print(f'Initialize configuration in {base_path}')

    # generate empty config dirs
    for d in CONFIG_DIRS:
        new_dir = base_path + '/' + d
        if not os.path.exists(new_dir):
            os.makedirs(new_dir)

    # copy template configs
    for template_file in TEMPLATE_FILES:
        copy_template_config(base_dir, template_file)


def copy_template_config(base_dir, config_path):
    """Copies template configuration files into custom folder

    :base_dir: path that contains template and custom folders
    :config_path: relative path of config to copy from template
    """
    custom_path = base_dir + '/' + CUSTOM_DIR + "/" + config_path
    template_path = base_dir + '/' + TEMPLATE_DIR + "/" + config_path

    logging.info(f'Copy {config_path} from {custom_path} to {template_path}')
    copy2(template_path, custom_path)


def generate_mosquitto_user_line(username, password):
    """Generates a line for a mosquitto user with a crypt hashed password

    :username: username to use
    :password: password that will be hashed (SHA512)

    :returns: a line as expected by mosquitto
    """
    password_hash = crypt.crypt(password, crypt.mksalt(crypt.METHOD_SHA512))
    line = f"{username}:{password_hash}"
    return line


def generate_sftp_user_line(username, password, directories=None):
    """Generates a line for a sftp user with a hashed password

    :username: username to use
    :password: password that will be hashed (SHA512)
    :directories: list of directories which the user should have

    :returns: a line as expected by sshd
    """
    # generate user line with hashed password
    password_hash = crypt.crypt(password, crypt.mksalt(crypt.METHOD_SHA512))
    line = f"{username}:{password_hash}:e:{UID}:{UID}"
    # add directory entries when available
    if directories:
        # create comma separated string from list
        dir_line = ','.join(d for d in directories)
        line = f"{line}:{dir_line}"
    return line


def generate_traefik_user_line(username, password):
    """Generates a line for a traefik user with a bcrypt hashed password

    :username: username to use
    :password: password that will be hashed (bcrypt)

    :returns: a line as expected by traefik
    """
    password_hash = bcrypt.hashpw(password.encode(), bcrypt.gensalt())
    line = f"{username}:{password_hash.decode()}"
    return line


def generate_mosquitto_file(base_dir, username, password):
    """Generates a mosquitto password file using mosquitto_passwd system tool

    :base_dir: path that contains custom config folder
    :username: username to use
    :password: password that will be used
    """
    passwd_path = base_dir + '/' + CUSTOM_DIR + "/" + EDIT_FILES[
        'mosquitto_passwords']

    # ensure file exists
    if not os.path.exists(passwd_path):
        open(passwd_path, 'a').close()

    # execute mosquitto passwd
    mos_result = run(
        ['mosquitto_passwd', '-b', passwd_path, username, password],
        universal_newlines=True)
    return mos_result.returncode == 0


def generate_sftp_file(base_dir, username, password, direcories=None):
    """Generates a sftp password file

    :base_dir: path that contains custom config folder
    :username: username to use
    :password: password that will be used
    :directories: list of directories which the user should have
    """
    # generate line and save it into a file
    file_content = generate_sftp_user_line(username, password, direcories)
    create_or_replace_config_file(base_dir, EDIT_FILES['sftp_users'],
                                  file_content)


def generate_id_rsa_files(base_dir):
    """Generates id_rsa and id_rsa.pub private/public keys using ssh-keygen

    :base_dir: path that contains custom config folder
    """
    id_path = base_dir + '/' + CUSTOM_DIR + "/" + EDIT_FILES['id_rsa']

    # execute ssh-keygen
    id_result = run(
        ['ssh-keygen', '-t', 'rsa', '-b', '4096', '-f', id_path, '-N', ''],
        universal_newlines=True, stdout=PIPE)
    return id_result.returncode == 0


def generate_host_key_files(base_dir, hosts):
    """Generates ssh host keys and matching known_hosts using ssh-keygen

    :base_dir: path that contains custom config folder
    """
    key_path = base_dir + '/' + CUSTOM_DIR + "/" + EDIT_FILES['host_key']
    # ssh-keygen generates public key with .pub postfix
    pub_path = key_path + '.pub'
    # host_names with sftp_ postfix
    sftp_hosts = [f'sftp_{host}' for host in hosts]

    # execute ssh-keygen
    id_result = run(['ssh-keygen', '-t', 'ed25519', '-f', key_path, '-N', ''],
                    universal_newlines=True, stdout=PIPE)

    # read content of public key as known line
    known_line = ""
    with open(pub_path, 'r') as pub_file:
        pub_line = pub_file.readline()
        split_line = pub_line.split()
        # delete last list element
        del split_line[-1]
        # collect sftp hosts as comma separated string
        hosts_line = ','.join(h for h in sftp_hosts)
        split_line.insert(0, hosts_line)
        # collect parts as space separated string
        known_line = ' '.join(sp for sp in split_line)

    # write new known_line file
    create_or_replace_config_file(base_dir, EDIT_FILES['known_hosts'],
                                  known_line)

    return id_result.returncode == 0


def generate_traefik_file(base_dir, username, password):
    """Generates a traefik password file

    :base_dir: path that contains custom config folder
    :username: username to use
    :password: password that will be used
    """
    # generate line and save it into a file
    file_content = generate_traefik_user_line(username, password)
    create_or_replace_config_file(base_dir, EDIT_FILES['traefik_users'],
                                  file_content)


def generate_volumerize_file(base_dir, hosts):
    """Generates config for volumerize backups

    :base_dir: path that contains custom config folder
    :hosts: names of backup hosts
    """
    configs = []

    for h in hosts:
        host_config = {
            'description': f'Backup Server on {h}',
            'url': f'sftp://ohadmin@sftp_{h}://home/ohadmin/backup_data/{h}'
        }
        configs.append(host_config)

    create_or_replace_config_file(
        base_dir, EDIT_FILES['backup_config'], configs, json=True)


def create_or_replace_config_file(base_dir, config_path, content, json=False):
    """Creates or replaces a config file with new content

    :base_dir: path that contains custom config folder
    :config_path: relative path of config
    :content: content of the file as a string
    """
    custom_path = base_dir + '/' + CUSTOM_DIR + "/" + config_path
    with open(custom_path, 'w+') as file:
        if json:
            import json
            json.dump(content, file, indent=2)
        else:
            file.write(content)


# }}}


# ******************************
# Docker machine functions {{{
# ******************************
def get_machine_list():
    """Get a list of docker machine names using the docker-machine system command

    :returns: a list of machine names managed by docker-machine
    """
    machine_result = run(['docker-machine', 'ls', '-q'],
                         universal_newlines=True,
                         stdout=PIPE)
    return machine_result.stdout.splitlines()


def check_machine_exists(machine_name):
    """Checks weather a docker machine exists and is available

    :machine_name: Name of the machine to check
    :returns: True when machine is available
    """
    machines = get_machine_list()

    return machine_name in machines


def get_machine_env(machine_name):
    """Gets dict of env settings from a machine

    :machine_name: Name of the machine to check
    :returns: Dict of env variables for this machine
    """
    env_result = run(['docker-machine', 'env', machine_name],
                     universal_newlines=True,
                     stdout=PIPE)

    machine_envs = {}

    lines = env_result.stdout.splitlines()
    for line in lines:
        if 'export' in line:
            assign = line.split('export ', 1)[1]
            env_entry = [a.strip('"') for a in assign.split('=', 1)]
            machine_envs[env_entry[0]] = env_entry[1]
    return machine_envs


def get_machine_ip(machine_name):
    """Asks for the ip of the docker machine

    :machine_name: Name of the machine to use for init
    """
    machine_result = run(['docker-machine', 'ip', machine_name],
                         universal_newlines=True,
                         stdout=PIPE)
    return machine_result.stdout.strip()


def init_swarm_machine(machine_name):
    """Creates a new swarm with the specified machine as leader

    :machine_name: Name of the machine to use for init
    :return: True if swarm init was successful
    """
    machine_ip = get_machine_ip(machine_name)
    init_command = 'docker swarm init --advertise-addr ' + machine_ip
    init_result = run(['docker-machine', 'ssh', machine_name, init_command],
                      universal_newlines=True)
    return init_result.returncode == 0


def join_swarm_machine(machine_name, leader_name):
    """Joins the swarm of the specified leader

    :machine_name: Name of the machine to join a swarm
    :leader_name: Name of the swarm leader machine
    :return: True if join to swarm was successful
    """
    token_command = 'docker swarm join-token manager -q'
    token_result = run(['docker-machine', 'ssh', leader_name, token_command],
                       universal_newlines=True,
                       stdout=PIPE)
    token = token_result.stdout.strip()
    leader_ip = get_machine_ip(leader_name)
    logging.info(f"Swarm leader with ip {leader_ip} uses token {token}")

    join_cmd = f'docker swarm join --token {token} {leader_ip}:{SWARM_PORT}'
    logging.info(f'Machine {machine_name} joins using command {join_cmd}')
    join_result = run(['docker-machine', 'ssh', machine_name, join_cmd],
                      universal_newlines=True)

    return join_result.returncode == 0


def generate_swarm(machines):
    """Generates a swarm, the first machine will be the initial leader

    :machines: list of machines in the swarm
    """
    leader = None
    for machine in machines:
        # init swarm with first machine
        if leader is None:
            leader = machine
            print(f'Create initial swarm with leader {leader}')
            if init_swarm_machine(leader):
                print('Swarm init successful\n')
                assign_label_to_node(leader, 'building',
                                     leader, manager=leader)
        else:
            print(f'Machine {machine} joins swarm of leader {leader}')
            if (join_swarm_machine(machine, leader)):
                print('Joining swarm successful\n')
                assign_label_to_node(machine, 'building',
                                     machine, manager=leader)


# }}}


# ******************************
# Docker client commands {{{
# ******************************
def assign_label_to_node(nodeid, label, value, manager=None):
    """Assigns a label to a node (e.g. building)

    :nodeid: Id or name of the node
    :label: Label you want to add
    :value: The value to assign to the label
    :manager: Dpcker machine to use for command, otherwise local
    """
    if manager:
        building_env = get_machine_env(manager)
        client = docker.from_env(environment=building_env)
    else:
        client = docker.from_env()

    node = client.nodes.get(nodeid)
    spec = node.attrs['Spec']
    spec['Labels'][label] = value
    node.update(spec)
    logging.info(f'Assign label {label} with value {value} to {nodeid}')

    client.close()


def run_command_in_service(service, command, building=None):
    """Runs a command in a service based on its name.
    When no matching container is found or the service name is ambigous
    an error will be displayed and the function exits

    :param service: Name of the service to execute command
    :param command: Command to execute
    :param building: Optional building, make service unambigous (Default: None)
    """

    if building:
        building_env = get_machine_env(building)
        client = docker.from_env(environment=building_env)
    else:
        client = docker.from_env()

    # Find containers matching name
    service_name_filter = {"name": service}
    containers = client.containers.list(filters=service_name_filter)

    # Ensure match is unambigous
    if (len(containers) > 1):
        print(f'Found multiple containers matching service name {service}, '
              'ensure service is unambigous')
    elif (len(containers) < 1):
        print(f'Found no matching container for service name {service}')
    else:
        service_container = containers[0]
        print(f'Executing {command} in container {service_container.name}'
              f'({service_container.id}) on building {building}')
        print(service_container.exec_run(command))
    client.close()


# }}}


# ******************************
# CLI base commands {{{
# ******************************
def init_config_dirs_command(args):
    """Initialize config directories

    :args: parsed commandline arguments
    """
    base_dir = args.base_dir

    if base_dir is None:
        base_dir = os.getcwd()

    # generate basic config folder
    generate_config_folders(base_dir)


def assign_building_command(args):
    """Assigns the role of a building to a node

    :args: parsed commandline arguments
    """
    node = args.node
    building = args.building

    print(f'Assign role of building {building} to node {node}')

    assign_label_to_node(node, 'building', building)


def execute_command(args):
    """Top level function to manage command executions from CLI

    :args: parsed commandline arguments
    """
    service = args.service
    command = " ".join(str(x) for x in args.command)  # list to string
    building = args.building

    run_command_in_service(service, command, building)


def restore_command(args):
    """Top level function to manage command executions from CLI

    :args: parsed commandline arguments
    """
    building = args.building
    target = args.target

    if not check_machine_exists(target):
        print(f'Machine with name {target} not found')
        return

    print(f'Restoring building {building} on machine {target}')

    get_machine_env(target)


def interactive_command(args):
    """Top level function to start the interactive mode

    :args: parsed command line arguments
    """
    main_menu(args)


# }}}


# ******************************
# Interactive menu entries {{{
# ******************************
def main_menu(args):
    """ Display main menu
    """
    # Base directory for configs
    base_dir = args.base_dir

    if base_dir is None:
        base_dir = os.getcwd()

    # Main menu prompts
    questions = [{
        'type': 'list',
        'name': 'main',
        'message': 'Public Building Manager - Main Menu',
        'choices': load_main_entires(base_dir)
    }]
    answers = prompt(questions)

    if 'Create' in answers['main']:
        init_menu(args)

    return answers


def init_menu(args):
    """Menu entry for initial setup and file generation
    """
    # Base directory for configs
    base_dir = args.base_dir

    if base_dir is None:
        base_dir = os.getcwd()

    # Prompts
    questions = [
        {
            'type': 'input',
            'name': 'stack_name',
            'message': 'Choose a name for your setup'
        },
        {
            'type': 'checkbox',
            'name': 'machines',
            'message': 'What docker machines will be used?',
            'choices': generate_checkbox_choices(get_machine_list())
        }
    ]
    answers = prompt(questions)

    # Ensure passwords match
    password_match = False
    while not password_match:
        password_questions = [{
            'type':
            'password',
            'name':
            'password',
            'message':
            'Choose a password for the ohadmin user:',
        },
            {
            'type':
            'password',
            'name':
            'confirm',
            'message':
            'Repeat password for the ohadmin user',
        }]
        password_answers = prompt(password_questions)
        if password_answers['password'] == password_answers['confirm']:
            password_match = True
        else:
            print("Passwords did not match, try again")

    # Initialize custom configuration dirs and templates
    generate_config_folders(base_dir)
    generate_initial_compose(base_dir)
    # Generate config files based on input
    username = ADMIN_USER
    password = password_answers['password']
    hosts = answers['machines']
    generate_sftp_file(base_dir, username, password)
    generate_mosquitto_file(base_dir, username, password)
    generate_traefik_file(base_dir, username, password)
    generate_volumerize_file(base_dir, hosts)
    generate_id_rsa_files(base_dir)
    generate_host_key_files(base_dir, hosts)

    for i, host in enumerate(hosts):
        init_machine_menu(base_dir, host, i)

    # print(answers)
    print(f"Configuration files generated in {base_dir}")

    # Check if changes shall be applied to docker environment
    generate_questions = [{
        'type': 'confirm',
        'name': 'generate',
        'message': 'Apply changes to docker environment?',
        'default': True
    }]
    generate_answers = prompt(generate_questions)

    if generate_answers['generate']:
        generate_swarm(answers['machines'])


def init_machine_menu(base_dir, host, increment):
    """Prompts to select server services

    :base_dir: Directory of config files
    :host: docker-machine host
    :increment: incrementing number to ensure ports are unique
    """
    # Prompt for services
    questions = [
        {
            'type': 'input',
            'name': 'buildingid',
            'message': f'Choose a name for building on server {host}'
        },
        {
            'type': 'checkbox',
            'name': 'services',
            'message': f'What services shall {host} provide?',
            'choices': generate_checkbox_choices(SERVICES.keys(), checked=True)
        }
    ]
    answers = prompt(questions)
    services = answers['services']
    if 'sftp' in services:
        add_sftp_service(base_dir, host, increment)
    if 'openhab' in services:
        add_openhab_service(base_dir, host)
    if 'nodered' in services:
        add_nodered_service(base_dir, host)
    if 'mqtt' in services:
        add_mqtt_service(base_dir, host, increment)
    print(answers)


def load_main_entires(base_dir):
    """Loads entries for main menu depending on available files

    :base_dir: directory of configuration files
    :returns: entries of main menu
    """
    custom_path = base_dir + '/' + CUSTOM_DIR

    entries = []
    if not os.path.exists(custom_path):
        entries.append('Create initial structure')
    else:
        entries.append('Execute command')

    entries.append('Exit')

    return entries


def generate_checkbox_choices(list, checked=False):
    """Generates checkbox entries for lists of strings

    :list: pyhton list that shall be converted
    :checked: if true, selections will be checked by default
    :returns: A list of dicts with name keys
    """
    return [{'name': m, 'checked': checked} for m in list]
# }}}


# ******************************
# Script main ( entry) {{{
# ******************************
if __name__ == '__main__':
    import argparse
    parser = argparse.ArgumentParser(
        prog='building_manager',
        description='Generate and manage multi'
        'building configurations of openHAB with docker swarm')
    parser.add_argument(
        '--base_dir',
        '-d',
        help='Directory to creat config folders in, default is current dir')
    subparsers = parser.add_subparsers()

    # Interactive mode
    parser_interactive = subparsers.add_parser(
        'interactive',
        help='Starts the interactive mode of the building manager')
    parser_interactive.set_defaults(func=interactive_command)

    # Restore command
    parser_restore = subparsers.add_parser('restore', help='Restore backups')
    parser_restore.add_argument(
        'building', help='Name (label) of the building that shall be restored')
    parser_restore.add_argument(
        'target', help='Name of the machine to restore to')
    parser_restore.set_defaults(func=restore_command)

    # Assign building command
    parser_assign_building = subparsers.add_parser(
        'assign_building', help='Assign the role of a building to a node')
    parser_assign_building.add_argument(
        'node', help='Name (or ID) of the node that gets the role assigned')
    parser_assign_building.add_argument(
        'building', help='Name of the building that will be assigned')
    parser_assign_building.set_defaults(func=assign_building_command)

    # Execute command
    parser_exec = subparsers.add_parser(
        'exec', help='Execute commands in a service container')
    parser_exec.add_argument(
        'service', help='Name of the service that will run the command')
    parser_exec.add_argument(
        'command', help='Command to be executed', nargs=argparse.REMAINDER)
    parser_exec.add_argument(
        '--building',
        '-b',
        help='Building name (label) of the service if '
        'service location is ambiguous')
    parser_exec.set_defaults(func=execute_command)

    # Config commands
    parser_config = subparsers.add_parser(
        'config', help='Manage configuration files')
    parser_config_subs = parser_config.add_subparsers()
    # - Config init
    parser_config_init = parser_config_subs.add_parser(
        'init', help='Initialize config file directories')
    parser_config_init.set_defaults(func=init_config_dirs_command)

    # Parse arguments into args dict
    args = parser.parse_args()

    # when no subcommand is defined show interactive menu
    try:
        args.func(args)
    except AttributeError:
        interactive_command(args)
# }}}

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