First commit

apps/channel_gateway/app/main.py

@@ -0,0 +1,112 @@
+from __future__ import annotations
+
+import logging
+from uuid import uuid4
+
+from fastapi import FastAPI, HTTPException, Request
+from fastapi.middleware.cors import CORSMiddleware
+
+from app.adapters.web import WebAdapter
+from app.adapters.whatsapp import WhatsAppAdapter
+from app.adapters.voice import VoiceAdapter
+from app.client import AgentFrameworkClient
+from app.schemas import GatewayRequest, VoiceTranscript, WebMessage, WhatsAppWebhook
+from app.settings import settings
+
+logging.basicConfig(level=settings.LOG_LEVEL)
+logger = logging.getLogger('external_channel_gateway')
+
+app = FastAPI(title='External Channel Gateway')
+app.add_middleware(
+    CORSMiddleware,
+    allow_origins=[o.strip() for o in settings.CORS_ORIGINS.split(',')],
+    allow_credentials=True,
+    allow_methods=['*'],
+    allow_headers=['*'],
+)
+
+client = AgentFrameworkClient()
+web_adapter = WebAdapter()
+whatsapp_adapter = WhatsAppAdapter()
+voice_adapter = VoiceAdapter()
+
+
+def _require_mode(expected: str, endpoint_type: str):
+    if settings.runtime_mode != expected:
+        raise HTTPException(
+            status_code=409,
+            detail={
+                'error_code': 'CHANNEL_GATEWAY_MODE_MISMATCH',
+                'message': f'{endpoint_type} endpoints require CHANNEL_GATEWAY_RUNTIME_MODE={expected}',
+                'current_runtime_mode': settings.runtime_mode,
+            },
+        )
+
+
+async def _forward(request: GatewayRequest) -> dict:
+    return await client.send(request)
+
+
+@app.get('/health')
+async def health():
+    return {
+        'status': 'ok',
+        'app_name': settings.APP_NAME,
+        'runtime_mode': settings.runtime_mode,
+        'configured_runtime_mode': settings.CHANNEL_GATEWAY_RUNTIME_MODE,
+        'legacy_channel_gateway_mode': settings.CHANNEL_GATEWAY_MODE,
+        'backend_url': client.url,
+        'default_tenant_id': settings.DEFAULT_TENANT_ID,
+        'default_agent_id': settings.DEFAULT_AGENT_ID,
+    }
+
+
+@app.post('/channels/web/message')
+async def web_message(payload: WebMessage, request: Request):
+    _require_mode('adapter', '/channels/*')
+    gateway_request = await web_adapter.to_gateway_request(payload)
+    gateway_request.payload.setdefault('metadata', {})
+    gateway_request.payload['metadata'].update({
+        'channel_gateway_request_id': request.headers.get('x-request-id') or str(uuid4()),
+        'channel_gateway_endpoint': '/channels/web/message',
+    })
+    return await _forward(gateway_request)
+
+
+@app.post('/channels/whatsapp/webhook')
+async def whatsapp_webhook(payload: WhatsAppWebhook, request: Request):
+    _require_mode('adapter', '/channels/*')
+    try:
+        gateway_request = await whatsapp_adapter.to_gateway_request(payload)
+    except ValueError as exc:
+        raise HTTPException(status_code=422, detail=str(exc)) from exc
+    gateway_request.payload.setdefault('metadata', {})
+    gateway_request.payload['metadata'].update({
+        'channel_gateway_request_id': request.headers.get('x-request-id') or str(uuid4()),
+        'channel_gateway_endpoint': '/channels/whatsapp/webhook',
+    })
+    return await _forward(gateway_request)
+
+
+@app.post('/channels/voice/transcript')
+async def voice_transcript(payload: VoiceTranscript, request: Request):
+    _require_mode('adapter', '/channels/*')
+    gateway_request = await voice_adapter.to_gateway_request(payload)
+    gateway_request.payload.setdefault('metadata', {})
+    gateway_request.payload['metadata'].update({
+        'channel_gateway_request_id': request.headers.get('x-request-id') or str(uuid4()),
+        'channel_gateway_endpoint': '/channels/voice/transcript',
+    })
+    return await _forward(gateway_request)
+
+
+@app.post('/gateway/message')
+async def proxy_gateway_message(payload: GatewayRequest, request: Request):
+    _require_mode('proxy', '/gateway/message')
+    payload.payload.setdefault('metadata', {})
+    payload.payload['metadata'].update({
+        'channel_gateway_request_id': request.headers.get('x-request-id') or str(uuid4()),
+        'channel_gateway_endpoint': '/gateway/message',
+        'proxied_by': settings.APP_NAME,
+    })
+    return await _forward(payload)