pyentrypoint/pyentrypoint/config.py

"""
    Configuration object
"""
from __future__ import absolute_import
from __future__ import unicode_literals

import os
from grp import getgrnam
from io import open
from pwd import getpwnam

from six import string_types
from yaml import load
from yaml import Loader

from .command import Command
from .constants import ENTRYPOINT_FILE
from .docker_links import DockerLinks
from .links import Links
from .logs import Logs
from .reloader import Reloader

__all__ = ['Config']


class ConfigMeta(object):

    def _return_item_lst(self, item):
        """Return item as a list"""
        if item in self._config:
            if isinstance(self._config[item], string_types):
                return [self._config[item]]
            return self._config[item]
        return []

    def get_templates(self):
        """Returns iterator of tuple (template, config_file)"""
        config_files = self.config_files
        if isinstance(config_files, list):
            for item in config_files:
                if isinstance(item, string_types):
                    template = item
                    outfile = item[:-4] if item.endswith('.tpl') else item
                if isinstance(item, dict):
                    template = list(item.keys())[0]
                    outfile = item[template]
                yield (template, outfile)
        else:
            raise Exception("config_files setup missformated.")

    def get_reloader(self):
        """Setup and get reloader"""
        config_files = [file[1] for file in self.get_templates()]
        reload = self._config['reload']
        if isinstance(reload, bool):
            return Reloader(files=config_files)
        if isinstance(reload, dict):
            signal = reload.get('signal', 'SIGHUP')
            watch_config_files = bool(reload.get('watch_config_files'))
            files = reload.get('files', [])
            if not isinstance(files, list):
                raise Exception('Reload files is not a list')
            if watch_config_files:
                files.extend(config_files)
            return Reloader(files=files, sig=signal)

    def _check_config(self):
        for key in self._config:
            if not hasattr(Config, key) or key == '__init__':
                self.log.warning(
                    '"{key}" is not a valid option'.format(key=key)
                )


class Config(ConfigMeta):

    """
    Get entrypoint config

    Parse entrypoint-config.yml

    Config file should always be in WORKDIR and named entrypoint-config.yml
    """

    def __init__(self, conf=ENTRYPOINT_FILE, args=[]):
        self._config = {}
        self.log = Logs().log
        self._args = args
        self._links = None
        self._command = None
        self._reload = None
        self._config_file = conf
        if not os.path.isfile(self._config_file):
            self.log.critical('Entrypoint config file does not provided')
            return
        with open(self._config_file) as f:
            self._config = load(stream=f, Loader=Loader)
        self._check_config()

    @property
    def has_config(self):
        "Has config file provided."
        return len(self._config) is not 0

    @property
    def command(self):
        "Main command to run."
        if self._command:
            return self._command
        cmd = self._args[0] if self._args else ''
        for key in ['command', 'cmd']:
            if key in self._config:
                cmd = self._config[key]
        self._command = Command(cmd, self, self._args)
        return self._command

    @property
    def subcommands(self):
        """Subcommands to handle as arguments."""
        rtn = self._return_item_lst('subcommands')
        if not rtn:
            return ['-*']
        return rtn

    @property
    def user(self):
        "Unix user or uid to run command."
        if 'user' in self._config:
            if isinstance(self._config['user'], int):
                return self._config['user']
            return getpwnam(self._config['user']).pw_uid
        return os.getuid()

    @property
    def group(self):
        "Unix group or gid to run command."
        if 'group' in self._config:
            if isinstance(self._config['user'], int):
                return self._config['user']
            return getgrnam(self._config['user']).gr_gid
        return os.getgid()

    @property
    def config_files(self):
        "List of template config files."
        return self._return_item_lst('config_files')

    @property
    def secret_env(self):
        """Environment variables to delete before running command."""
        return self._return_item_lst('secret_env')

    @property
    def links(self):
        """Links configs singleton."""
        if self._links:
            return self._links
        if 'links' not in self._config:
            self._links = Links(links=DockerLinks())
            return self._links
        self._links = Links(config=self._config['links'], links=DockerLinks())
        for name in self._config['links']:
            self._links._add_name(name)
        return self._links

    @property
    def pre_conf_commands(self):
        """Return list of preconf commands"""
        return self._return_item_lst('pre_conf_commands')

    @property
    def post_conf_commands(self):
        """Return list of postconf commands"""
        return self._return_item_lst('post_conf_commands')

    @property
    def reload(self):
        """Return Reloader object if reload is set"""
        if self._reload:
            return self._reload
        if not self._config.get('reload'):
            return None
        self._reload = self.get_reloader()
        return self._reload

    @property
    def clean_env(self):
        """Clean env from linked containers before running command"""
        if 'clean_env' in self._config:
            return bool(self._config['clean_env'])
        return True

    @property
    def debug(self):
        """Enable debug logs."""
        if 'ENTRYPOINT_DEBUG' in os.environ:
            return True
        if 'debug' in self._config:
            return bool(self._config['debug'])
        return False

    @property
    def quiet(self):
        """Disable logging"""
        if self.debug:
            return False
        if 'ENTRYPOINT_QUIET' in os.environ:
            return True
        return bool(self._config.get('quiet', False))