Fix Ollama chat reliability

backend/app/routes/chat.py

@@ -9,6 +9,7 @@ Flux :
 from __future__ import annotations
 
 import json
+import logging
 
 from fastapi import APIRouter, HTTPException
 from fastapi.responses import StreamingResponse
@@ -19,6 +20,7 @@ from ..agent import run_agent
 from ..config import settings
 
 router = APIRouter(prefix="/api", tags=["chat"])
+logger = logging.getLogger(__name__)
 
 
 class ChatRequest(BaseModel):
@@ -54,20 +56,38 @@ async def chat(req: ChatRequest) -> StreamingResponse:
         yield _sse("start", {"model": model})
         final_content = ""
         tools_meta: list[dict] = []
+        error_message = ""
 
-        async for ev in run_agent(
-            model,
-            convo,
-            options=agent_config.ollama_options(cfg),
-            enabled_tools=agent_config.enabled_tool_names(cfg),
-            confirm_shell=cfg.get("confirm_shell", True),
-        ):
-            etype = ev.pop("type")
-            if etype in ("token", "tool_call", "tool_result", "tool_confirm", "error"):
-                yield _sse(etype, ev)
-            elif etype == "final":
-                final_content = ev["content"]
-                tools_meta = ev["tools"]
+        try:
+            async for ev in run_agent(
+                model,
+                convo,
+                options=agent_config.ollama_options(cfg),
+                enabled_tools=agent_config.enabled_tool_names(cfg),
+                confirm_shell=cfg.get("confirm_shell", True),
+            ):
+                etype = ev.pop("type")
+                if etype in (
+                    "token",
+                    "status",
+                    "notice",
+                    "tool_call",
+                    "tool_result",
+                    "tool_confirm",
+                ):
+                    yield _sse(etype, ev)
+                elif etype == "error":
+                    error_message = ev.get("message", "Erreur Ollama inconnue")
+                    yield _sse("error", {"message": error_message})
+                elif etype == "final":
+                    final_content = ev["content"]
+                    tools_meta = ev["tools"]
+        except Exception as exc:
+            # Après l'envoi des en-têtes SSE, une exception non gérée coupe le
+            # socket sans explication et laisse l'interface bloquée.
+            logger.exception("Échec inattendu du flux de chat")
+            error_message = f"Erreur interne du chat : {exc}"
+            yield _sse("error", {"message": error_message})
 
         if final_content or tools_meta:
             db.add_message(
@@ -77,6 +97,20 @@ async def chat(req: ChatRequest) -> StreamingResponse:
                 model,
                 meta={"tools": tools_meta} if tools_meta else None,
             )
-        yield _sse("done", {"content": final_content, "tools": tools_meta})
+        yield _sse(
+            "done",
+            {
+                "content": final_content,
+                "tools": tools_meta,
+                "error": error_message or None,
+            },
+        )
 
-    return StreamingResponse(event_stream(), media_type="text/event-stream")
+    return StreamingResponse(
+        event_stream(),
+        media_type="text/event-stream",
+        headers={
+            "Cache-Control": "no-cache, no-transform",
+            "X-Accel-Buffering": "no",
+        },
+    )