Refactor health checks to log warnings and return fallback messages on failures

- Updated Redis and ChromaDB health check functions to log warnings instead of raising exceptions on connectivity failures.
- Implemented fallback mechanisms to use in-memory storage when Redis or ChromaDB is unavailable.
- Modified tests to assert warnings are generated instead of exceptions being raised during health check failures.

Author: Wojciech Napierała

core/health.py

@@ -50,7 +50,12 @@ def _check_redis(config: AppConfig) -> List[str]:
     try:
         client.ping()
     except Exception as exc:  # pragma: no cover - runtime dependent
-        raise HealthCheckError(f"Redis connectivity check failed: {exc}") from exc
+        LOGGER.warning(
+            "Redis connectivity check failed (%s); using in-memory fallback.", exc
+        )
+        return [
+            "redis unavailable; using in-memory working memory fallback.",
+        ]
     return []
 
 
@@ -69,7 +74,13 @@ def _check_chromadb(config: AppConfig) -> List[str]:
         client = cast(Any, chromadb_module).PersistentClient(path=str(persist_dir))
         client.list_collections()
     except Exception as exc:  # pragma: no cover - runtime dependent
-        raise HealthCheckError(f"ChromaDB availability check failed: {exc}") from exc
+        LOGGER.warning(
+            "ChromaDB availability check failed (%s); using in-memory memory store.",
+            exc,
+        )
+        return [
+            "chromadb unavailable; in-memory persistence activated.",
+        ]
     return []
 
 

core/memory_manager.py

@@ -385,6 +385,11 @@ def __init__(self, config: AppConfig) -> None:
 
         self._embedding_fn = self._build_embedding_function(config)
         self._supports_vector_query = self._embedding_fn is not None
+        if not self._supports_vector_query:
+            self._logger.warning(
+                "Chroma embedding function unavailable; storing memory in-process."
+            )
+            return
 
         try:  # pragma: no cover - needs chromadb runtime
             self._client = chromadb_module.PersistentClient(

tests/test_health.py

@@ -13,7 +13,6 @@
 import pytest
 
 from config import settings
-from core.exceptions import HealthCheckError
 from core.health import run_startup_checks
 
 
@@ -70,14 +69,15 @@ def test_health_checks_with_stubbed_dependencies(monkeypatch: pytest.MonkeyPatch
     assert warnings == []
 
 
-def test_health_checks_raise_on_redis_failure(monkeypatch: pytest.MonkeyPatch, tmp_path: Path) -> None:
+def test_health_checks_warn_on_redis_failure(monkeypatch: pytest.MonkeyPatch, tmp_path: Path) -> None:
     config = _load_config(tmp_path)
     config.memory.chromadb.persist_directory = str(tmp_path / "chroma")
 
     _install_stub_modules(monkeypatch, tmp_path, redis_ping_ok=False)
 
-    with pytest.raises(HealthCheckError):
-        run_startup_checks(config)
+    warnings = run_startup_checks(config)
+    assert warnings
+    assert any("redis unavailable" in warning for warning in warnings)
 
 
 def test_health_checks_warn_when_standard_embedding_missing(monkeypatch: pytest.MonkeyPatch, tmp_path: Path) -> None: