fix(embed): fast-fail + auto-restart Ollama on solved-search hang

Embeddings timeout was 120s, causing multi-minute hangs when Ollama was
down during F4/F6/F7 solved-search. Now: connect_timeout=5s across all
HTTP clients (REST + Ollama), read_timeout reduced to 30s for embeddings,
and OllamaEmbeddings auto-restarts the server on ConnectionError before
degrading gracefully.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

harness/tests/test_rest_client.py

@@ -51,7 +51,7 @@ def test_run_query_payload_and_rows(monkeypatch):
     assert c["url"] == "https://h/dwh/rpc/run_query"
     assert c["json"] == {"query_text": "SELECT 1 AS x"}
     assert c["headers"]["X-API-Key"] == "dwh_k"
-    assert c["timeout"] == 30
+    assert c["timeout"] == (5, 30)
 
 
 def test_explain_query_maps_lines(monkeypatch):

harness/tht/config.py

@@ -52,6 +52,7 @@ class RestConfig(BaseModel):
     base_url: str
     api_key: str
     timeout: int = 30
+    connect_timeout: int = 5
     ssl_ca: str | None = None  # path al certificato CA (per server con CA interna)
 
 
@@ -105,7 +106,8 @@ class EmbeddingsConfig(BaseModel):
     model: str = "nomic-embed-text-v2-moe"
     dim: int = 768
     batch_size: int = 32
-    timeout: int = 120
+    timeout: int = 30
+    connect_timeout: int = 5
     bin: str = "ollama"
     start_cmd: list[str] | None = None
 

harness/tht/rest/client.py

@@ -28,7 +28,7 @@ class RestClient:
                 url,
                 json=args,
                 headers={"X-API-Key": self.cfg.api_key},
-                timeout=self.cfg.timeout,
+                timeout=(self.cfg.connect_timeout, self.cfg.timeout),
                 verify=verify,
             )
         except requests.RequestException as e:

harness/tht/vectorstore/embeddings.py

@@ -1,3 +1,7 @@
+import subprocess
+import sys
+import time
+
 import requests
 
 from tht.config import EmbeddingsConfig
@@ -5,6 +9,9 @@ from tht.config import EmbeddingsConfig
 DOC_PREFIX = "search_document: "
 QUERY_PREFIX = "search_query: "
 
+_RESTART_WAIT = 8  # secondi di attesa dopo aver avviato Ollama
+_RESTART_POLL = 1.0
+
 
 class EmbeddingsError(Exception):
     pass
@@ -17,17 +24,64 @@ class OllamaEmbeddings:
     def __init__(self, cfg: EmbeddingsConfig):
         self.cfg = cfg
 
+    def _is_up(self) -> bool:
+        try:
+            r = requests.get(
+                f"{self.cfg.base_url.rstrip('/')}/api/tags",
+                timeout=(self.cfg.connect_timeout, 5),
+            )
+            return r.status_code == 200
+        except requests.RequestException:
+            return False
+
+    def _try_restart(self) -> bool:
+        """Tenta di avviare Ollama e attende che sia raggiungibile."""
+        start_cmd = self.cfg.start_cmd if self.cfg.start_cmd is not None else [self.cfg.bin, "serve"]
+        if not start_cmd:
+            return False
+        try:
+            subprocess.Popen(  # noqa: S603
+                start_cmd, start_new_session=True,
+                stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL,
+            )
+        except Exception:  # noqa: BLE001
+            return False
+        print("[embeddings] Ollama non raggiungibile, avvio in corso…", file=sys.stderr)
+        deadline = time.monotonic() + _RESTART_WAIT
+        while time.monotonic() < deadline:
+            time.sleep(_RESTART_POLL)
+            if self._is_up():
+                return True
+        return False
+
+    def _post(self, url: str, batch: list[str]) -> requests.Response:
+        resp = requests.post(
+            url, json={"model": self.cfg.model, "input": batch},
+            timeout=(self.cfg.connect_timeout, self.cfg.timeout),
+        )
+        resp.raise_for_status()
+        return resp
+
     def _embed(self, texts: list[str]) -> list[list[float]]:
         url = f"{self.cfg.base_url.rstrip('/')}/api/embed"
         out: list[list[float]] = []
         for i in range(0, len(texts), self.cfg.batch_size):
             batch = texts[i : i + self.cfg.batch_size]
             try:
-                resp = requests.post(
-                    url, json={"model": self.cfg.model, "input": batch},
-                    timeout=self.cfg.timeout,
-                )
-                resp.raise_for_status()
+                resp = self._post(url, batch)
+            except requests.ConnectionError:
+                if not self._try_restart():
+                    raise EmbeddingsError(
+                        f"Ollama non raggiungibile su {self.cfg.base_url} "
+                        f"(modello {self.cfg.model}), avvio automatico fallito"
+                    )
+                try:
+                    resp = self._post(url, batch)
+                except requests.RequestException as e:
+                    raise EmbeddingsError(
+                        f"Ollama non raggiungibile su {self.cfg.base_url} "
+                        f"(modello {self.cfg.model}): {e}"
+                    ) from e
             except requests.RequestException as e:
                 raise EmbeddingsError(
                     f"Ollama non raggiungibile su {self.cfg.base_url} "

harness/tht/vectorstore/rest_client.py

@@ -33,7 +33,7 @@ class VectorRestClient:
                 url,
                 json=args,
                 headers={"X-API-Key": self.cfg.api_key},
-                timeout=self.cfg.timeout,
+                timeout=(self.cfg.connect_timeout, self.cfg.timeout),
                 verify=verify,
             )
         except requests.RequestException as e: