Store instance database engine in database

maubot/db/__init__.py

@@ -1,7 +1,7 @@
 from mautrix.util.async_db import Database
 
 from .client import Client
-from .instance import Instance
+from .instance import DatabaseEngine, Instance
 from .upgrade import upgrade_table
 
 
@@ -10,4 +10,4 @@ def init(db: Database) -> None:
         table.db = db
 
 
-__all__ = ["upgrade_table", "init", "Client", "Instance"]
+__all__ = ["upgrade_table", "init", "Client", "Instance", "DatabaseEngine"]

maubot/db/instance.py

@@ -16,6 +16,7 @@
 from __future__ import annotations
 
 from typing import TYPE_CHECKING, ClassVar
+from enum import Enum
 
 from asyncpg import Record
 from attr import dataclass
@@ -26,6 +27,11 @@ from mautrix.util.async_db import Database
 fake_db = Database.create("") if TYPE_CHECKING else None
 
 
+class DatabaseEngine(Enum):
+    SQLITE = "sqlite"
+    POSTGRES = "postgres"
+
+
 @dataclass
 class Instance:
     db: ClassVar[Database] = fake_db
@@ -35,21 +41,31 @@ class Instance:
     enabled: bool
     primary_user: UserID
     config_str: str
+    database_engine: DatabaseEngine | None
+
+    @property
+    def database_engine_str(self) -> str | None:
+        return self.database_engine.value if self.database_engine else None
 
     @classmethod
     def _from_row(cls, row: Record | None) -> Instance | None:
         if row is None:
             return None
-        return cls(**row)
+        data = {**row}
+        db_engine = data.pop("database_engine", None)
+        return cls(**data, database_engine=DatabaseEngine(db_engine) if db_engine else None)
+
+    _columns = "id, type, enabled, primary_user, config, database_engine"
 
     @classmethod
     async def all(cls) -> list[Instance]:
-        rows = await cls.db.fetch("SELECT id, type, enabled, primary_user, config FROM instance")
+        q = f"SELECT {cls._columns} FROM instance"
+        rows = await cls.db.fetch(q)
         return [cls._from_row(row) for row in rows]
 
     @classmethod
     async def get(cls, id: str) -> Instance | None:
-        q = "SELECT id, type, enabled, primary_user, config FROM instance WHERE id=$1"
+        q = f"SELECT {cls._columns} FROM instance WHERE id=$1"
         return cls._from_row(await cls.db.fetchrow(q, id))
 
     async def update_id(self, new_id: str) -> None:
@@ -58,17 +74,27 @@ class Instance:
 
     @property
     def _values(self):
-        return self.id, self.type, self.enabled, self.primary_user, self.config_str
+        return (
+            self.id,
+            self.type,
+            self.enabled,
+            self.primary_user,
+            self.config_str,
+            self.database_engine_str,
+        )
 
     async def insert(self) -> None:
         q = (
-            "INSERT INTO instance (id, type, enabled, primary_user, config) "
-            "VALUES ($1, $2, $3, $4, $5)"
+            "INSERT INTO instance (id, type, enabled, primary_user, config, database_engine) "
+            "VALUES ($1, $2, $3, $4, $5, $6)"
         )
         await self.db.execute(q, *self._values)
 
     async def update(self) -> None:
-        q = "UPDATE instance SET type=$2, enabled=$3, primary_user=$4, config=$5 WHERE id=$1"
+        q = """
+        UPDATE instance SET type=$2, enabled=$3, primary_user=$4, config=$5, database_engine=$6
+        WHERE id=$1
+        """
         await self.db.execute(q, *self._values)
 
     async def delete(self) -> None:

maubot/db/upgrade/__init__.py

@@ -2,4 +2,4 @@ from mautrix.util.async_db import UpgradeTable
 
 upgrade_table = UpgradeTable()
 
-from . import v01_initial_revision
+from . import v01_initial_revision, v02_instance_database_engine

maubot/db/upgrade/v02_instance_database_engine.py

@@ -0,0 +1,25 @@
+# maubot - A plugin-based Matrix bot system.
+# Copyright (C) 2022 Tulir Asokan
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+from __future__ import annotations
+
+from mautrix.util.async_db import Connection
+
+from . import upgrade_table
+
+
+@upgrade_table.register(description="Store instance database engine")
+async def upgrade_v2(conn: Connection) -> None:
+    await conn.execute("ALTER TABLE instance ADD COLUMN database_engine TEXT")

maubot/instance.py

@@ -34,7 +34,7 @@ from mautrix.util.config import BaseProxyConfig, RecursiveDict
 from mautrix.util.logging import TraceLogger
 
 from .client import Client
-from .db import Instance as DBInstance
+from .db import DatabaseEngine, Instance as DBInstance
 from .lib.plugin_db import ProxyPostgresDatabase
 from .loader import DatabaseType, PluginLoader, ZippedPluginLoader
 from .plugin_base import Plugin
@@ -71,10 +71,21 @@ class PluginInstance(DBInstance):
     started: bool
 
     def __init__(
-        self, id: str, type: str, enabled: bool, primary_user: UserID, config: str = ""
+        self,
+        id: str,
+        type: str,
+        enabled: bool,
+        primary_user: UserID,
+        config: str = "",
+        database_engine: DatabaseEngine | None = None,
     ) -> None:
         super().__init__(
-            id=id, type=type, enabled=bool(enabled), primary_user=primary_user, config_str=config
+            id=id,
+            type=type,
+            enabled=bool(enabled),
+            primary_user=primary_user,
+            config_str=config,
+            database_engine=database_engine,
         )
 
     def __hash__(self) -> int:
@@ -111,6 +122,8 @@ class PluginInstance(DBInstance):
             "database": (
                 self.inst_db is not None and self.maubot.config["api_features.instance_database"]
             ),
+            "database_interface": self.loader.meta.database_type_str if self.loader else "unknown",
+            "database_engine": self.database_engine_str,
         }
 
     def _introspect_sqlalchemy(self) -> dict:
@@ -269,12 +282,27 @@ class PluginInstance(DBInstance):
         self, upgrade_table: UpgradeTable | None = None, actually_start: bool = True
     ) -> None:
         if self.loader.meta.database_type == DatabaseType.SQLALCHEMY:
+            if self.database_engine is None:
+                await self.update_db_engine(DatabaseEngine.SQLITE)
+            elif self.database_engine == DatabaseEngine.POSTGRES:
+                raise RuntimeError(
+                    "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}")
         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:
+                    await self.update_db_engine(DatabaseEngine.SQLITE)
+                else:
+                    await self.update_db_engine(DatabaseEngine.POSTGRES)
             instance_db_log = db_log.getChild(self.id)
-            # TODO should there be a way to choose between SQLite and Postgres
-            #      for individual instances? Maybe checking the existence of the SQLite file.
-            if self.maubot.plugin_postgres_db:
+            if self.database_engine == DatabaseEngine.POSTGRES:
+                if not self.maubot.plugin_postgres_db:
+                    raise RuntimeError(
+                        "Instance database engine is marked as Postgres, but this maubot isn't "
+                        "configured to support Postgres for plugin databases"
+                    )
                 self.inst_db = ProxyPostgresDatabase(
                     pool=self.maubot.plugin_postgres_db,
                     instance_id=self.id,
@@ -334,7 +362,12 @@ class PluginInstance(DBInstance):
             self.log.debug("Disabling webapp after plugin meta reload")
             self.disable_webapp()
         if self.loader.meta.database:
-            await self.start_database(cls.get_db_upgrade_table())
+            try:
+                await self.start_database(cls.get_db_upgrade_table())
+            except Exception:
+                self.log.exception("Failed to start instance database")
+                await self.update_enabled(False)
+                return
         config_class = cls.get_config_class()
         if config_class:
             try:
@@ -455,6 +488,11 @@ class PluginInstance(DBInstance):
             self.enabled = enabled
             await self.update()
 
+    async def update_db_engine(self, db_engine: DatabaseEngine | None) -> None:
+        if db_engine is not None and db_engine != self.database_engine:
+            self.database_engine = db_engine
+            await self.update()
+
     @classmethod
     @async_getter_lock
     async def get(

maubot/loader/meta.py

@@ -13,7 +13,7 @@
 #
 # You should have received a copy of the GNU Affero General Public License
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
-from typing import List
+from typing import List, Optional
 
 from attr import dataclass
 from packaging.version import InvalidVersion, Version
@@ -63,3 +63,7 @@ class PluginMeta(SerializableAttrs):
     extra_files: List[str] = []
     dependencies: List[str] = []
     soft_dependencies: List[str] = []
+
+    @property
+    def database_type_str(self) -> Optional[str]:
+        return self.database_type.value if self.database else None

maubot/management/frontend/src/pages/dashboard/Instance.js

@@ -43,7 +43,7 @@ class Instance extends BaseMainView {
     }
 
     get entryKeys() {
-        return ["id", "primary_user", "enabled", "started", "type", "config"]
+        return ["id", "primary_user", "enabled", "started", "type", "config", "database_engine"]
     }
 
     get initialState() {
@@ -54,6 +54,7 @@ class Instance extends BaseMainView {
             started: true,
             type: "",
             config: "",
+            database_engine: "",
 
             saving: false,
             deleting: false,