platypush/platypush/entities/_base.py
2023-09-26 23:50:10 +02:00

366 lines
11 KiB
Python

import logging
import inspect
import json
import os
import pathlib
import subprocess
import sys
import types
from datetime import datetime
from typing import Callable, Dict, List, Optional, Set, Type, Tuple, Any
import pkgutil
from dateutil.tz import tzutc
from sqlalchemy import (
Boolean,
Column,
DateTime,
ForeignKey,
Index,
Integer,
JSON,
String,
UniqueConstraint,
inspect as schema_inspect,
)
from sqlalchemy.engine import Engine
from sqlalchemy.orm import ColumnProperty, backref, relationship
from sqlalchemy.orm.exc import ObjectDeletedError
import platypush
from platypush.config import Config
from platypush.common.db import Base
from platypush.message import JSONAble, Message
EntityRegistryType = Dict[str, Type['Entity']]
entities_registry: EntityRegistryType = {}
EntityKey = Tuple[str, str]
""" The entity's logical key, as an ``<external_id, plugin>`` tuple. """
EntityMapping = Dict[EntityKey, 'Entity']
""" Internal mapping for entities used for deduplication/merge/upsert. """
_import_error_ignored_modules: Set[str] = {'bluetooth'}
"""
ImportError exceptions will be ignored for these entity submodules when
imported dynamically. An ImportError for these modules means that some optional
requirements are missing, and if those plugins aren't enabled then we shouldn't
fail.
"""
logger = logging.getLogger(__name__)
if 'entity' not in Base.metadata:
class Entity(Base):
"""
Model for a general-purpose platform entity.
"""
__tablename__ = 'entity'
id = Column(Integer, autoincrement=True, primary_key=True)
external_id = Column(String, nullable=False)
name = Column(String, nullable=False, index=True)
description = Column(String)
type = Column(String, nullable=False, index=True)
plugin = Column(String, nullable=False)
parent_id = Column(
Integer,
ForeignKey(f'{__tablename__}.id', ondelete='CASCADE'),
nullable=True,
)
data = Column(JSON, default=dict)
meta = Column(JSON, default=dict)
is_read_only = Column(Boolean, default=False)
is_write_only = Column(Boolean, default=False)
is_query_disabled = Column(Boolean, default=False)
is_configuration = Column(Boolean, default=False)
external_url = Column(String)
image_url = Column(String)
created_at = Column(
DateTime(timezone=False), default=datetime.utcnow(), nullable=False
)
updated_at = Column(
DateTime(timezone=False),
default=datetime.utcnow(),
onupdate=datetime.utcnow(),
)
parent = relationship(
'Entity',
remote_side=[id],
uselist=False,
lazy='joined',
post_update=True,
backref=backref(
'children',
remote_side=[parent_id],
uselist=True,
cascade='all, delete-orphan',
lazy='immediate',
),
)
UniqueConstraint(external_id, plugin)
__table_args__ = (
Index('name_and_plugin_index', name, plugin),
Index('name_type_and_plugin_index', name, type, plugin),
{'extend_existing': True},
)
__mapper_args__ = {
'polymorphic_identity': __tablename__,
'polymorphic_on': type,
}
@classmethod
def get_columns(cls) -> Tuple[ColumnProperty, ...]:
inspector = schema_inspect(cls)
return tuple(inspector.mapper.column_attrs)
@property
def entity_key(self) -> EntityKey:
"""
This method returns the "external" key of an entity.
"""
return str(self.external_id), str(self.plugin)
def copy(self) -> 'Entity':
"""
This method returns a copy of the entity. It's useful when you want
to reuse entity objects in other threads or outside of their
associated SQLAlchemy session context.
"""
def key_value_pair(col: ColumnProperty):
try:
return (col.key, getattr(self, col.key, None))
except ObjectDeletedError:
return None
return self.__class__(
**dict(
key_value_pair(col) # type: ignore
for col in self.get_columns()
if key_value_pair(col) is not None
),
children=[child.copy() for child in self.children],
)
def _serialize_value(self, column_name: str) -> Any:
val = getattr(self, column_name)
if isinstance(val, datetime):
# All entity timestamps are in UTC
val = val.replace(tzinfo=tzutc()).isoformat()
return val
def _column_name(self, col: ColumnProperty) -> Optional[str]:
"""
Normalizes the column name, taking into account native columns and
columns mapped to properties.
"""
try:
normalized_name = col.key.lstrip('_')
if len(col.key.lstrip('_')) == col.key or not hasattr(
self, normalized_name
):
return col.key # It's not a hidden column with a mapped property
return normalized_name
except ObjectDeletedError as e:
logger.warning(
'Could not access column "%s" for entity ID "{%s}": {%s}',
col.key,
self.id,
e,
)
return None
def _column_to_pair(self, col: ColumnProperty) -> tuple:
"""
Utility method that, given a column, returns a pair containing its
normalized name and its serialized value.
"""
col_name = self._column_name(col)
if col_name is None:
return ()
return col_name, self._serialize_value(col_name)
@property
def children_ids(self) -> List[int]:
"""
Returns the children IDs of the entity.
"""
children_ids = []
for child in self.children:
try:
children_ids.append(child.id)
except ObjectDeletedError:
pass
return children_ids
def to_dict(self) -> dict:
"""
Returns the current entity as a flatten dictionary.
"""
return {
**dict(
self._column_to_pair(col)
for col in self.get_columns()
if self._column_to_pair(col)
),
'children_ids': self.children_ids,
}
def to_json(self) -> dict:
"""
Alias for :meth:`.to_dict`.
"""
return self.to_dict()
def __repr__(self):
"""
Same as :meth:`.__str__`.
"""
return str(self)
def __str__(self):
"""
:return: A JSON-encoded representation of the entity.
"""
return json.dumps(self.to_dict(), cls=Message.Encoder)
def __setattr__(self, key, value):
"""
Serializes the new value before assigning it to an attribute.
"""
matching_columns = [c for c in self.get_columns() if c.expression.name == key] # type: ignore
if (
matching_columns
and issubclass(type(matching_columns[0].columns[0].type), DateTime)
and isinstance(value, str)
):
value = datetime.fromisoformat(value)
return super().__setattr__(key, value)
def get_plugin(self):
from platypush.context import get_plugin
plugin = get_plugin(self.plugin)
assert plugin, f'No such plugin: {plugin}'
return plugin
def run(self, action: str, *args, **kwargs):
plugin = self.get_plugin()
method = getattr(plugin, action, None)
assert method, f'No such action: {self.plugin}.{action}'
return method(self.external_id or self.name, *args, **kwargs)
# Inject the JSONAble mixin (Python goes nuts if done through
# standard multiple inheritance with an SQLAlchemy ORM class)
Entity.__bases__ = Entity.__bases__ + (JSONAble,)
EntitySavedCallback = Callable[[Entity], Any]
"""
Type for the callback functions that should be called when an entity is saved
on the database.
"""
def _discover_entity_types():
for loader, modname, _ in pkgutil.walk_packages(
path=[str(pathlib.Path(__file__).parent.absolute())],
prefix=__package__ + '.',
onerror=lambda _: None,
):
try:
mod_loader = loader.find_spec(modname, None)
assert mod_loader and mod_loader.loader
module = types.ModuleType(mod_loader.name)
mod_loader.loader.exec_module(module)
except Exception as e:
if (
isinstance(e, (ImportError, ModuleNotFoundError))
and modname[len(__package__) + 1 :] in _import_error_ignored_modules
):
logger.debug('Could not import module %s', modname)
else:
logger.warning('Could not import module %s', modname)
logger.exception(e)
continue
for _, obj in inspect.getmembers(module):
if inspect.isclass(obj) and issubclass(obj, Entity):
entities_registry[obj] = {} # type: ignore
def _get_db():
"""
Utility method to get the db plugin.
"""
from platypush.context import get_plugin
db = get_plugin('db')
assert db
return db
def _get_db_engine() -> Engine:
"""
Utility method to get the db engine.
"""
return _get_db().get_engine()
def get_entities_registry() -> EntityRegistryType:
"""
:returns: A copy of the entities registry.
"""
return entities_registry.copy()
def init_entities_db():
"""
Initializes the entities database.
"""
run_db_migrations()
_discover_entity_types()
_get_db().create_all(_get_db_engine(), Base)
def run_db_migrations():
"""
Run the database migrations upon engine initialization.
"""
logger.info('Running database migrations')
alembic_ini = os.path.join(
os.path.dirname(inspect.getabsfile(platypush)), 'migrations', 'alembic.ini'
)
subprocess.run(
[
sys.executable,
'-m',
'alembic',
'-c',
alembic_ini,
'-x',
f'CFGFILE={Config.get_file()}',
'-x',
f'DBNAME={_get_db_engine().url}',
'upgrade',
'head',
],
check=True,
)