config.py

#!/usr/bin/env python
"""Config for scriptworker

Attributes:
    log (logging.Logger): the log object for the module.
    CREDS_FILES (tuple): an ordered list of files to look for taskcluster
        credentials, if they aren't in the config file or environment.
"""
from copy import deepcopy
from frozendict import frozendict
import json
import logging
import os
import re
import sys

from scriptworker.constants import DEFAULT_CONFIG

log = logging.getLogger(__name__)

CREDS_FILES = (
    os.path.join(os.getcwd(), 'secrets.json'),
    os.path.join(os.environ.get('HOME', '/etc/'), '.scriptworker'),
)

# Based on
# https://github.com/taskcluster/taskcluster-queue/blob/ced3b7bd824b445fd33ce0deb5de87a65f02b8b3/src/api.js#L94
_GENERIC_ID_REGEX = re.compile(r'^[a-zA-Z0-9-_]{1,22}$')


def freeze_values(dictionary):
    """Convert a dictionary's list values into tuples, and dicts into frozendicts.

    This won't recurse; it's best for relatively flat data structures.

    Args:
        dictionary (dict): the dictionary to modify in-place.
    """
    for key, value in dictionary.items():
        if isinstance(value, list):
            dictionary[key] = tuple(value)
        elif isinstance(value, dict):
            dictionary[key] = frozendict(value)


def read_worker_creds(key="credentials"):
    """Get credentials from CREDS_FILES or the environment.

    This looks at the CREDS_FILES in order, and falls back to the environment.

    Args:
        key (str, optional): each CREDS_FILE is a json dict.  This key's value
            contains the credentials.  Defaults to 'credentials'.

    Returns:
        dict: the credentials found. None if no credentials found.
    """
    for path in CREDS_FILES:
        if not os.path.exists(path):
            continue
        with open(path, "r") as fh:
            try:
                contents = json.load(fh)
                return contents[key]
            except (json.decoder.JSONDecodeError, KeyError):
                pass
    else:
        if key == "credentials" and os.environ.get("TASKCLUSTER_ACCESS_TOKEN") and \
                os.environ.get("TASKCLUSTER_CLIENT_ID"):
            credentials = {
                "accessToken": os.environ["TASKCLUSTER_ACCESS_TOKEN"],
                "clientId": os.environ["TASKCLUSTER_CLIENT_ID"],
            }
            if os.environ.get("TASKCLUSTER_CERTIFICATE"):
                credentials['certificate'] = os.environ['TASKCLUSTER_CERTIFICATE']
            return credentials


def check_config(config, path):
    """Validate the config against DEFAULT_CONFIG.

    Any unknown keys or wrong types will add error messages.

    Args:
        config (dict): the running config.
        path (str): the path to the config file, used in error messages.

    Returns:
        list: the error messages found when validating the config.
    """
    messages = []
    for key, value in config.items():
        if key not in DEFAULT_CONFIG:
            messages.append("Unknown key {} in {}!".format(key, path))
            continue
        if DEFAULT_CONFIG[key] is not None:
            value_type = type(value)
            default_type = type(DEFAULT_CONFIG[key])
            if value_type != default_type:
                messages.append(
                    "{} {}: type {} is not {}!".format(path, key, value_type, default_type)
                )
        if value in ("...", b"..."):
            messages.append("{} {} needs to be defined!".format(path, key))
        if key in ("gpg_public_keyring", "gpg_secret_keyring") and not value.startswith('%(gpg_home)s/'):
            messages.append("{} needs to start with %(gpg_home)s/ to be portable!".format(key))
        if key in ("provisioner_id", "worker_group", "worker_type", "worker_id") and not _is_id_valid(value):
            messages.append('{} doesn\'t match "{}" (required by Taskcluster)'.format(key, _GENERIC_ID_REGEX.pattern))
    return messages


def _is_id_valid(id_string):
    return _GENERIC_ID_REGEX.match(id_string) is not None


# create_config {{{1
def create_config(path="config.json"):
    """Create a config from DEFAULT_CONFIG, arguments, and config file.

    Then validate it and freeze it.

    Args:
        path (str, optional): the path to the config file.  Defaults to "config.json"

    Returns:
        tuple: (config dict, credentials dict)
    """
    if not os.path.exists(path):
        print("{} doesn't exist! Exiting create_config()...".format(path),
              file=sys.stderr)
        print("Exiting...", file=sys.stderr)
        sys.exit(1)
    with open(path, "r", encoding="utf-8") as fh:
        secrets = json.load(fh)
    config = dict(deepcopy(DEFAULT_CONFIG))
    if not secrets.get("credentials"):
        secrets['credentials'] = read_worker_creds()
    freeze_values(secrets)
    config.update(secrets)
    messages = check_config(config, path)
    if messages:
        print('\n'.join(messages), file=sys.stderr)
        print("Exiting...", file=sys.stderr)
        sys.exit(1)
    credentials = frozendict(secrets['credentials'])
    del(config['credentials'])
    config = frozendict(config)
    return config, credentials