factory.py

'''@factory

This file is the acting web server.

@debug, enables debugging, and tracebacks
@host, tells the OS (guest VM) to accept connections from all public IP
    addresses.

Note: both the handler, and logger has levels. If the level of the logger is
      higher than that of the handler, no messages will be handled by the
      corresponding handler.

'''

import yaml
import logging
from log.logger import Logger
from logging.handlers import RotatingFileHandler
from flask import Flask
from interface.views import blueprint


# application factory
def create_app(args={'prefix': '', 'settings': ''}):
    # define configuration
    with open(args['prefix'] + 'hiera/settings.yaml', 'r') as stream:
        try:
            # local variables
            if args['settings']:
                app = Flask(
                    __name__,
                    args['settings'],
                    template_folder='interface/templates',
                    static_folder='interface/static',
                )
            else:
                app = Flask(
                    __name__,
                    template_folder='interface/templates',
                    static_folder='interface/static',
                )
            settings = yaml.load(stream)

            # register blueprint
            app.register_blueprint(blueprint)

            # local logger: used for this module
            root = settings['general']['root']
            LOG_PATH = root + settings['webserver']['flask_log_path']
            HANDLER_LEVEL = settings['application']['log_level']

            # flask attributes: accessible across application
            app.config.update(
                HOST=settings['general']['host'],
                PORT_REDIS=settings['redis']['port'],
                ROOT=settings['general']['root'],
                DB_LOG_PATH=settings['database']['log_path'],
                DB_ML=settings['database']['name'],
                DB_USERNAME=settings['database']['username'],
                DB_PASSWORD=settings['database']['password'],
                LOG_LEVEL=HANDLER_LEVEL,
                FLASK_LOG_PATH=settings['webserver']['flask_log_path'],
                ERROR_LOG_PATH=settings['application']['error_log_path'],
                WARNING_LOG_PATH=settings['application']['warning_log_path'],
                INFO_LOG_PATH=settings['application']['info_log_path'],
                DEBUG_LOG_PATH=settings['application']['debug_log_path'],
                MODEL_TYPE=settings['application']['model_type']
            )
        except yaml.YAMLError as error:
            logger = Logger('error', 'yaml')
            logger.log(error)

    # log handler: requires the below logger
    formatter = logging.Formatter(
        "[%(asctime)s] {%(pathname)s:%(lineno)d} %(levelname)s - %(message)s")
    handler = RotatingFileHandler(LOG_PATH, maxBytes=10000000, backupCount=5)
    handler.setLevel(HANDLER_LEVEL)
    handler.setFormatter(formatter)
    app.logger.addHandler(handler)

    # logger: complements the log handler
    log = logging.getLogger('werkzeug')
    log.setLevel(logging.DEBUG)
    log.addHandler(handler)

    # return
    return app