Let plugins add their endpoints to the main webserver

example-config.yaml

@@ -26,6 +26,8 @@ server:
     base_path: /_matrix/maubot/v1
     # The base path for the UI.
     ui_base_path: /_matrix/maubot
+    # The base path for plugin endpoints. {id} is replaced with the ID of the instance.
+    plugin_base_path: /_matrix/maubot/plugin/{id}
     # Override path from where to load UI resources.
     # Set to false to using pkg_resources to find the path.
     override_resource_path: false

maubot/__main__.py

@@ -58,10 +58,10 @@ loop = asyncio.get_event_loop()
 init_zip_loader(config)
 db_session = init_db(config)
 clients = init_client_class(db_session, loop)
-plugins = init_plugin_instance_class(db_session, config, loop)
 management_api = init_mgmt_api(config, loop)
 server = MaubotServer(config, loop)
 server.app.add_subapp(config["server.base_path"], management_api)
+plugins = init_plugin_instance_class(db_session, config, server.app, loop)
 
 for plugin in plugins:
     plugin.load()

maubot/config.py

@@ -41,6 +41,7 @@ class Config(BaseFileConfig):
         copy("server.listen")
         copy("server.base_path")
         copy("server.ui_base_path")
+        copy("server.plugin_base_path")
         copy("server.override_resource_path")
         copy("server.appservice_base_path")
         shared_secret = self["server.unshared_secret"]

maubot/instance.py

@@ -13,8 +13,9 @@
 #
 # 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 Dict, List, Optional
+from typing import Dict, List, Optional, TYPE_CHECKING
 from asyncio import AbstractEventLoop
+from aiohttp import web
 import os.path
 import logging
 import io
@@ -33,6 +34,9 @@ from .client import Client
 from .loader import PluginLoader, ZippedPluginLoader
 from .plugin_base import Plugin
 
+if TYPE_CHECKING:
+    from .server import MaubotServer
+
 log = logging.getLogger("maubot.instance")
 
 yaml = YAML()
@@ -41,6 +45,7 @@ yaml.indent(4)
 
 class PluginInstance:
     db: Session = None
+    webserver: 'MaubotServer' = None
     mb_config: Config = None
     loop: AbstractEventLoop = None
     cache: Dict[str, 'PluginInstance'] = {}
@@ -54,6 +59,7 @@ class PluginInstance:
     base_cfg: RecursiveDict[CommentedMap]
     inst_db: sql.engine.Engine
     inst_db_tables: Dict[str, sql.Table]
+    inst_webapp: web.Application
     started: bool
 
     def __init__(self, db_instance: DBPlugin):
@@ -66,6 +72,7 @@ class PluginInstance:
         self.plugin = None
         self.inst_db = None
         self.inst_db_tables = None
+        self.inst_webapp = None
         self.base_cfg = None
         self.cache[self.id] = self
 
@@ -105,6 +112,8 @@ class PluginInstance:
         if self.loader.meta.database:
             db_path = os.path.join(self.mb_config["plugin_directories.db"], self.id)
             self.inst_db = sql.create_engine(f"sqlite:///{db_path}.db")
+        if self.loader.meta.webapp:
+            self.inst_webapp = self.webserver.get_instance_subapp(self.id)
         self.log.debug("Plugin instance dependencies loaded")
         self.loader.references.add(self)
         self.client.references.add(self)
@@ -126,6 +135,8 @@ class PluginInstance:
             ZippedPluginLoader.trash(
                 os.path.join(self.mb_config["plugin_directories.db"], f"{self.id}.db"),
                 reason="deleted")
+        if self.inst_webapp:
+            self.webserver.remove_instance_webapp(self.id)
 
     def load_config(self) -> CommentedMap:
         return yaml.load(self.db_instance.config)
@@ -157,7 +168,7 @@ class PluginInstance:
             self.config = config_class(self.load_config, lambda: self.base_cfg, self.save_config)
         self.plugin = cls(client=self.client.client, loop=self.loop, http=self.client.http_client,
                           instance_id=self.id, log=self.log, config=self.config,
-                          database=self.inst_db)
+                          database=self.inst_db, webapp=self.inst_webapp)
         try:
             await self.plugin.start()
         except Exception:
@@ -274,8 +285,10 @@ class PluginInstance:
     # endregion
 
 
-def init(db: Session, config: Config, loop: AbstractEventLoop) -> List[PluginInstance]:
+def init(db: Session, config: Config, webserver: 'MaubotServer', loop: AbstractEventLoop) -> List[
+    PluginInstance]:
     PluginInstance.db = db
     PluginInstance.mb_config = config
     PluginInstance.loop = loop
+    PluginInstance.webserver = webserver
     return PluginInstance.all()

maubot/loader/abc.py

@@ -57,6 +57,7 @@ class PluginMeta(SerializableAttrs['PluginMeta']):
 
     maubot: Version = Version(__version__)
     database: bool = False
+    webapp: bool = False
     license: str = ""
     extra_files: List[str] = []
     dependencies: List[str] = []

maubot/plugin_base.py

@@ -17,7 +17,7 @@ from typing import Type, Optional, TYPE_CHECKING
 from abc import ABC
 from logging import Logger
 from asyncio import AbstractEventLoop
-import functools
+from aiohttp.web import Application
 
 from sqlalchemy.engine.base import Engine
 from aiohttp import ClientSession
@@ -37,7 +37,7 @@ class Plugin(ABC):
 
     def __init__(self, client: 'MaubotMatrixClient', loop: AbstractEventLoop, http: ClientSession,
                  instance_id: str, log: Logger, config: Optional['BaseProxyConfig'],
-                 database: Optional[Engine]) -> None:
+                 database: Optional[Engine], webapp: Optional[Application]) -> None:
         self.client = client
         self.loop = loop
         self.http = http
@@ -45,6 +45,7 @@ class Plugin(ABC):
         self.log = log
         self.config = config
         self.database = database
+        self.webapp = webapp
         self._handlers_at_startup = []
 
     async def start(self) -> None:

maubot/server.py

@@ -43,11 +43,29 @@ class MaubotServer:
 
         as_path = PathBuilder(config["server.appservice_base_path"])
         self.add_route(Method.PUT, as_path.transactions, self.handle_transaction)
+        self.subapps = {}
 
         self.setup_management_ui()
 
         self.runner = web.AppRunner(self.app, access_log_class=AccessLogger)
 
+    def get_instance_subapp(self, instance_id: str) -> web.Application:
+        try:
+            return self.subapps[instance_id]
+        except KeyError:
+            app = web.Application(loop=self.loop)
+            self.app.add_subapp(self.config["server.plugin_base_path"].format(id=instance_id), app)
+            self.subapps[instance_id] = app
+            return app
+
+    def remove_instance_webapp(self, instance_id: str) -> None:
+        try:
+            subapp: web.Application = self.subapps.pop(instance_id)
+        except KeyError:
+            return
+        subapp.shutdown()
+        subapp.cleanup()
+
     def setup_management_ui(self) -> None:
         ui_base = self.config["server.ui_base_path"]
         if ui_base == "/":