Add configurable adapter selection to app runner

youdis.py

@@ -1,5 +1,5 @@
 #!/usr/bin/env python3
-"""App runner for the standard v2 stack."""
+"""App runner for FastAPI backend and discord adapter."""
 
 from __future__ import annotations
 
@@ -22,6 +22,7 @@ DEFAULT_BACKEND_HOST = os.getenv("YOUDIS_BACKEND_HOST", "127.0.0.1")
 DEFAULT_BACKEND_PORT = int(os.getenv("YOUDIS_BACKEND_PORT", "8000"))
 RUN_BACKEND = os.getenv("YOUDIS_RUN_BACKEND", "1") not in {"0", "false", "False"}
 RUN_DISCORD = os.getenv("YOUDIS_RUN_DISCORD", "1") not in {"0", "false", "False"}
+ENABLED_ADAPTERS = os.getenv("YOUDIS_ENABLED_ADAPTERS", "discord")
 BACKEND_HEALTH_TIMEOUT = float(os.getenv("YOUDIS_BACKEND_HEALTH_TIMEOUT", "20"))
 BACKEND_HEALTH_INTERVAL = float(os.getenv("YOUDIS_BACKEND_HEALTH_INTERVAL", "0.5"))
 
@@ -69,6 +70,23 @@ async def start_discord(env: dict[str, str]) -> ManagedProcess:
     return ManagedProcess(name="discord", process=process)
 
 
+ADAPTER_STARTERS = {
+    "discord": start_discord,
+}
+
+
+def selected_adapters() -> list[str]:
+    requested = [name.strip() for name in ENABLED_ADAPTERS.split(",") if name.strip()]
+    if not RUN_DISCORD:
+        requested = [name for name in requested if name != "discord"]
+
+    unknown = [name for name in requested if name not in ADAPTER_STARTERS]
+    if unknown:
+        raise ValueError(f"unknown adapters requested: {', '.join(sorted(unknown))}")
+
+    return requested
+
+
 async def wait_for_backend_health(timeout_seconds: float) -> None:
     deadline = asyncio.get_running_loop().time() + timeout_seconds
     health_url = f"{backend_url()}/health"
@@ -102,9 +120,10 @@ async def stop_process(proc: ManagedProcess) -> None:
 async def run() -> int:
     managed: list[ManagedProcess] = []
     env = build_child_env()
+    adapters = selected_adapters()
 
-    if not RUN_BACKEND and not RUN_DISCORD:
-        print("nothing to start: both YOUDIS_RUN_BACKEND and YOUDIS_RUN_DISCORD are disabled")
+    if not RUN_BACKEND and not adapters:
+        print("nothing to start: backend is disabled and no adapters are enabled")
         return 1
 
     try:
@@ -115,10 +134,10 @@ async def run() -> int:
             await wait_for_backend_health(BACKEND_HEALTH_TIMEOUT)
             print("backend is healthy")
 
-        if RUN_DISCORD:
-            discord = await start_discord(env)
-            managed.append(discord)
-            print("started discord adapter")
+        for adapter_name in adapters:
+            process = await ADAPTER_STARTERS[adapter_name](env)
+            managed.append(process)
+            print(f"started {adapter_name} adapter")
 
         wait_tasks = [asyncio.create_task(proc.process.wait()) for proc in managed]
         done, pending = await asyncio.wait(wait_tasks, return_when=asyncio.FIRST_COMPLETED)