fix: restart embedding server when passages change

tests/test_embedding_server_manager.py

@@ -0,0 +1,137 @@
+import json
+import time
+
+import pytest
+from leann.embedding_server_manager import EmbeddingServerManager
+
+
+class DummyProcess:
+    def __init__(self):
+        self.pid = 12345
+        self._terminated = False
+
+    def poll(self):
+        return 0 if self._terminated else None
+
+    def terminate(self):
+        self._terminated = True
+
+    def kill(self):
+        self._terminated = True
+
+    def wait(self, timeout=None):
+        self._terminated = True
+        return 0
+
+
+@pytest.fixture
+def embedding_manager(monkeypatch):
+    manager = EmbeddingServerManager("leann_backend_hnsw.hnsw_embedding_server")
+
+    def fake_get_available_port(start_port):
+        return start_port
+
+    monkeypatch.setattr(
+        "leann.embedding_server_manager._get_available_port",
+        fake_get_available_port,
+    )
+
+    start_calls = []
+
+    def fake_start_new_server(self, port, model_name, embedding_mode, **kwargs):
+        config_signature = kwargs.get("config_signature")
+        start_calls.append(config_signature)
+        self.server_process = DummyProcess()
+        self.server_port = port
+        self._server_config = config_signature
+        return True, port
+
+    monkeypatch.setattr(
+        EmbeddingServerManager,
+        "_start_new_server",
+        fake_start_new_server,
+    )
+
+    # Ensure stop_server doesn't try to operate on real subprocesses
+    def fake_stop_server(self):
+        self.server_process = None
+        self.server_port = None
+        self._server_config = None
+
+    monkeypatch.setattr(EmbeddingServerManager, "stop_server", fake_stop_server)
+
+    return manager, start_calls
+
+
+def _write_meta(meta_path, passages_name, index_name, total):
+    meta_path.write_text(
+        json.dumps(
+            {
+                "backend_name": "hnsw",
+                "embedding_model": "test-model",
+                "embedding_mode": "sentence-transformers",
+                "dimensions": 3,
+                "backend_kwargs": {},
+                "passage_sources": [
+                    {
+                        "type": "jsonl",
+                        "path": passages_name,
+                        "index_path": index_name,
+                    }
+                ],
+                "total_passages": total,
+            }
+        ),
+        encoding="utf-8",
+    )
+
+
+def test_server_restarts_when_metadata_changes(tmp_path, embedding_manager):
+    manager, start_calls = embedding_manager
+
+    meta_path = tmp_path / "example.meta.json"
+    passages_path = tmp_path / "example.passages.jsonl"
+    index_path = tmp_path / "example.passages.idx"
+
+    passages_path.write_text("first\n", encoding="utf-8")
+    index_path.write_bytes(b"index")
+    _write_meta(meta_path, passages_path.name, index_path.name, total=1)
+
+    # Initial start populates signature
+    ok, port = manager.start_server(
+        port=6000,
+        model_name="test-model",
+        passages_file=str(meta_path),
+    )
+    assert ok
+    assert port == 6000
+    assert len(start_calls) == 1
+
+    initial_signature = start_calls[0]["passages_signature"]
+
+    # No metadata change => reuse existing server
+    ok, port_again = manager.start_server(
+        port=6000,
+        model_name="test-model",
+        passages_file=str(meta_path),
+    )
+    assert ok
+    assert port_again == 6000
+    assert len(start_calls) == 1
+
+    # Modify passage data and metadata to force signature change
+    time.sleep(0.01)  # Ensure filesystem timestamps move forward
+    passages_path.write_text("second\n", encoding="utf-8")
+    _write_meta(meta_path, passages_path.name, index_path.name, total=2)
+
+    ok, port_third = manager.start_server(
+        port=6000,
+        model_name="test-model",
+        passages_file=str(meta_path),
+    )
+    assert ok
+    assert port_third == 6000
+    assert len(start_calls) == 2
+
+    updated_signature = start_calls[1]["passages_signature"]
+    assert updated_signature != initial_signature