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