Remove hard dependency on SQLAlchemy

Fixes #247

maubot/instance.py

@@ -25,7 +25,6 @@ import os.path
 
 from ruamel.yaml import YAML
 from ruamel.yaml.comments import CommentedMap
-import sqlalchemy as sql
 
 from mautrix.types import UserID
 from mautrix.util import background_task
@@ -36,6 +35,7 @@ from mautrix.util.logging import TraceLogger
 
 from .client import Client
 from .db import DatabaseEngine, Instance as DBInstance
+from .lib.optionalalchemy import Engine, MetaData, create_engine
 from .lib.plugin_db import ProxyPostgresDatabase
 from .loader import DatabaseType, PluginLoader, ZippedPluginLoader
 from .plugin_base import Plugin
@@ -128,7 +128,7 @@ class PluginInstance(DBInstance):
         }
 
     def _introspect_sqlalchemy(self) -> dict:
-        metadata = sql.MetaData()
+        metadata = MetaData()
         metadata.reflect(self.inst_db)
         return {
             table.name: {
@@ -214,7 +214,7 @@ class PluginInstance(DBInstance):
 
     async def get_db_tables(self) -> dict:
         if self.inst_db_tables is None:
-            if isinstance(self.inst_db, sql.engine.Engine):
+            if isinstance(self.inst_db, Engine):
                 self.inst_db_tables = self._introspect_sqlalchemy()
             elif self.inst_db.scheme == Scheme.SQLITE:
                 self.inst_db_tables = await self._introspect_sqlite()
@@ -294,7 +294,7 @@ class PluginInstance(DBInstance):
                     "Instance database engine is marked as Postgres, but plugin uses legacy "
                     "database interface, which doesn't support postgres."
                 )
-            self.inst_db = sql.create_engine(f"sqlite:///{self._sqlite_db_path}")
+            self.inst_db = create_engine(f"sqlite:///{self._sqlite_db_path}")
         elif self.loader.meta.database_type == DatabaseType.ASYNCPG:
             if self.database_engine is None:
                 if os.path.exists(self._sqlite_db_path) or not self.maubot.plugin_postgres_db:
@@ -329,7 +329,7 @@ class PluginInstance(DBInstance):
     async def stop_database(self) -> None:
         if isinstance(self.inst_db, Database):
             await self.inst_db.stop()
-        elif isinstance(self.inst_db, sql.engine.Engine):
+        elif isinstance(self.inst_db, Engine):
             self.inst_db.dispose()
         else:
             raise RuntimeError(f"Unknown database type {type(self.inst_db).__name__}")

maubot/lib/optionalalchemy.py

@@ -0,0 +1,19 @@
+try:
+    from sqlalchemy import MetaData, asc, create_engine, desc
+    from sqlalchemy.engine import Engine
+    from sqlalchemy.exc import IntegrityError, OperationalError
+except ImportError:
+
+    class FakeError(Exception):
+        pass
+
+    class FakeType:
+        def __init__(self, *args, **kwargs):
+            raise Exception("SQLAlchemy is not installed")
+
+    def create_engine(*args, **kwargs):
+        raise Exception("SQLAlchemy is not installed")
+
+    MetaData = Engine = FakeType
+    IntegrityError = OperationalError = FakeError
+    asc = desc = lambda a: a

maubot/loader/zip.py

@@ -31,7 +31,7 @@ from ..config import Config
 from ..lib.zipimport import ZipImportError, zipimporter
 from ..plugin_base import Plugin
 from .abc import IDConflictError, PluginClass, PluginLoader
-from .meta import PluginMeta
+from .meta import DatabaseType, PluginMeta
 
 current_version = Version(__version__)
 yaml = YAML()
@@ -155,9 +155,9 @@ class ZippedPluginLoader(PluginLoader):
         return file, meta
 
     @classmethod
-    def verify_meta(cls, source) -> tuple[str, Version]:
+    def verify_meta(cls, source) -> tuple[str, Version, DatabaseType | None]:
         _, meta = cls._read_meta(source)
-        return meta.id, meta.version
+        return meta.id, meta.version, meta.database_type if meta.database else None
 
     def _load_meta(self) -> None:
         file, meta = self._read_meta(self.path)

maubot/management/api/instance_database.py

@@ -19,12 +19,12 @@ from datetime import datetime
 
 from aiohttp import web
 from asyncpg import PostgresError
-from sqlalchemy import asc, desc, engine, exc
 import aiosqlite
 
 from mautrix.util.async_db import Database
 
 from ...instance import PluginInstance
+from ...lib.optionalalchemy import Engine, IntegrityError, OperationalError, asc, desc
 from .base import routes
 from .responses import resp
 
@@ -66,7 +66,7 @@ async def get_table(request: web.Request) -> web.Response:
     except KeyError:
         order = []
     limit = int(request.query.get("limit", "100"))
-    if isinstance(instance.inst_db, engine.Engine):
+    if isinstance(instance.inst_db, Engine):
         return _execute_query_sqlalchemy(instance, table.select().order_by(*order).limit(limit))
 
 
@@ -84,7 +84,7 @@ async def query(request: web.Request) -> web.Response:
     except KeyError:
         return resp.query_missing
     rows_as_dict = data.get("rows_as_dict", False)
-    if isinstance(instance.inst_db, engine.Engine):
+    if isinstance(instance.inst_db, Engine):
         return _execute_query_sqlalchemy(instance, sql_query, rows_as_dict)
     elif isinstance(instance.inst_db, Database):
         try:
@@ -133,12 +133,12 @@ async def _execute_query_asyncpg(
 def _execute_query_sqlalchemy(
     instance: PluginInstance, sql_query: str, rows_as_dict: bool = False
 ) -> web.Response:
-    assert isinstance(instance.inst_db, engine.Engine)
+    assert isinstance(instance.inst_db, Engine)
     try:
         res = instance.inst_db.execute(sql_query)
-    except exc.IntegrityError as e:
+    except IntegrityError as e:
         return resp.sql_integrity_error(e, sql_query)
-    except exc.OperationalError as e:
+    except OperationalError as e:
         return resp.sql_operational_error(e, sql_query)
     data = {
         "ok": True,

maubot/management/api/plugin_upload.py

@@ -23,10 +23,17 @@ import traceback
 from aiohttp import web
 from packaging.version import Version
 
-from ...loader import MaubotZipImportError, PluginLoader, ZippedPluginLoader
+from ...loader import DatabaseType, MaubotZipImportError, PluginLoader, ZippedPluginLoader
 from .base import get_config, routes
 from .responses import resp
 
+try:
+    import sqlalchemy
+
+    has_alchemy = True
+except ImportError:
+    has_alchemy = False
+
 log = logging.getLogger("maubot.server.upload")
 
 
@@ -36,9 +43,11 @@ async def put_plugin(request: web.Request) -> web.Response:
     content = await request.read()
     file = BytesIO(content)
     try:
-        pid, version = ZippedPluginLoader.verify_meta(file)
+        pid, version, db_type = ZippedPluginLoader.verify_meta(file)
     except MaubotZipImportError as e:
         return resp.plugin_import_error(str(e), traceback.format_exc())
+    if db_type == DatabaseType.SQLALCHEMY and not has_alchemy:
+        return resp.sqlalchemy_not_installed
     if pid != plugin_id:
         return resp.pid_mismatch
     plugin = PluginLoader.id_cache.get(plugin_id, None)
@@ -55,9 +64,11 @@ async def upload_plugin(request: web.Request) -> web.Response:
     content = await request.read()
     file = BytesIO(content)
     try:
-        pid, version = ZippedPluginLoader.verify_meta(file)
+        pid, version, db_type = ZippedPluginLoader.verify_meta(file)
     except MaubotZipImportError as e:
         return resp.plugin_import_error(str(e), traceback.format_exc())
+    if db_type == DatabaseType.SQLALCHEMY and not has_alchemy:
+        return resp.sqlalchemy_not_installed
     plugin = PluginLoader.id_cache.get(pid, None)
     if not plugin:
         return await upload_new_plugin(content, pid, version)

maubot/management/api/responses.py

@@ -15,13 +15,16 @@
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
 from __future__ import annotations
 
+from typing import TYPE_CHECKING
 from http import HTTPStatus
 
 from aiohttp import web
 from asyncpg import PostgresError
-from sqlalchemy.exc import IntegrityError, OperationalError
 import aiosqlite
 
+if TYPE_CHECKING:
+    from sqlalchemy.exc import IntegrityError, OperationalError
+
 
 class _Response:
     @property
@@ -324,6 +327,16 @@ class _Response:
             }
         )
 
+    @property
+    def sqlalchemy_not_installed(self) -> web.Response:
+        return web.json_response(
+            {
+                "error": "This plugin requires a legacy database, but SQLAlchemy is not installed",
+                "errcode": "unsupported_plugin_database",
+            },
+            status=HTTPStatus.NOT_IMPLEMENTED,
+        )
+
     @property
     def table_not_found(self) -> web.Response:
         return web.json_response(

maubot/plugin_base.py

@@ -20,7 +20,6 @@ from abc import ABC
 from asyncio import AbstractEventLoop
 
 from aiohttp import ClientSession
-from sqlalchemy.engine.base import Engine
 from yarl import URL
 
 from mautrix.util.async_db import Database, UpgradeTable
@@ -30,6 +29,8 @@ from mautrix.util.logging import TraceLogger
 from .scheduler import BasicScheduler
 
 if TYPE_CHECKING:
+    from sqlalchemy.engine.base import Engine
+
     from .client import MaubotMatrixClient
     from .loader import BasePluginLoader
     from .plugin_server import PluginWebApp
@@ -56,7 +57,7 @@ class Plugin(ABC):
         instance_id: str,
         log: TraceLogger,
         config: BaseProxyConfig | None,
-        database: Engine | None,
+        database: Engine | Database | None,
         webapp: PluginWebApp | None,
         webapp_url: str | None,
         loader: BasePluginLoader,

optional-requirements.txt

@@ -9,3 +9,6 @@ unpaddedbase64>=1,<3
 #/testing
 pytest
 pytest-asyncio
+
+#/legacydb
+SQLAlchemy>1,<1.4

requirements.txt

@@ -1,7 +1,6 @@
 mautrix>=0.20.6,<0.21
 aiohttp>=3,<4
 yarl>=1,<2
-SQLAlchemy>=1,<1.4
 asyncpg>=0.20,<0.30
 aiosqlite>=0.16,<0.21
 commonmark>=0.9,<1