from platypush.config import Config from platypush.context import get_plugin from platypush.plugins import Plugin, action class VariablePlugin(Plugin): """ This plugin allows you to manipulate context variables that can be accessed across your tasks. It requires the :mod:`platypush.plugins.db` and :mod:`platypush.plugins.redis` plugins to be enabled, as the variables will be stored either persisted on a local database or on the local Redis instance. Requires: * **sqlalchemy** (``pip install sqlalchemy``) * **redis** (``pip install redis``) """ _variable_table_name = 'variable' def __init__(self, *args, **kwargs): """ The plugin will create a table named ``variable`` on the database configured in the :mod:`platypush.plugins.db` plugin. You'll have to specify a default ``engine`` in your ``db`` plugin configuration. """ super().__init__(*args, **kwargs) self.db_plugin = get_plugin('db') self.redis_plugin = get_plugin('redis') db = Config.get('db') self.db_config = { 'engine': db.get('engine'), 'args': db.get('args', []), 'kwargs': db.get('kwargs', {}) } self._create_tables() # self._variables = {} def _create_tables(self): self.db_plugin.execute("""CREATE TABLE IF NOT EXISTS {}( name varchar(255) not null primary key, value text )""".format(self._variable_table_name)) @action def get(self, name, default_value=None): """ Get the value of a variable by name from the local db. :param name: Variable name :type name: str :param default_value: What will be returned if the variable is not defined (default: None) :returns: A map in the format ``{"":""}`` """ rows = self.db_plugin.select(table=self._variable_table_name, filter={'name': name}, engine=self.db_config['engine'], *self.db_config['args'], **self.db_config['kwargs']).output return {name: rows[0]['value'] if rows else None} @action def set(self, **kwargs): """ Set a variable or a set of variables on the local db. :param kwargs: Key-value list of variables to set (e.g. ``foo='bar', answer=42``) """ records = [ { 'name': k, 'value': v } for (k,v) in kwargs.items() ] self.db_plugin.insert(table=self._variable_table_name, records=records, key_columns=['name'], engine=self.db_config['engine'], on_duplicate_update=True, *self.db_config['args'], **self.db_config['kwargs']) return kwargs @action def unset(self, name): """ Unset a variable by name if it's set on the local db. :param name: Name of the variable to remove :type name: str """ records = [ { 'name': name } ] self.db_plugin.delete(table=self._variable_table_name, records=records, engine=self.db_config['engine'], *self.db_config['args'], **self.db_config['kwargs']) return True @action def mget(self, name): """ Get the value of a variable by name from Redis. :param name: Variable name :type name: str :param default_value: What will be returned if the variable is not defined (default: None) :returns: A map in the format ``{"":""}`` """ return self.redis_plugin.mget([name]) @action def mset(self, **kwargs): """ Set a variable or a set of variables on Redis. :param kwargs: Key-value list of variables to set (e.g. ``foo='bar', answer=42``) :returns: A map with the set variables """ self.redis_plugin.mset(**kwargs) return kwargs @action def munset(self, name): """ Unset a Redis variable by name if it's set :param name: Name of the variable to remove :type name: str """ return self.redis_plugin.delete(name) @action def expire(self, name, expire): """ Set a variable expiration on Redis :param name: Variable name :type name: str :param expire: Expiration time in seconds :type expire: int """ return self.redis_plugin.expire(name, expire) # vim:sw=4:ts=4:et: