README.md

@@ -12,6 +12,8 @@ Subclass an adapter in your own repository to add domain-specific methods while
 | **Adapters**     | Technology-specific base classes (`RedisAdapter`, `MinioAdapter`) |
 | **Your project** | Subclass an adapter and add domain methods                        |
 
+Connection adapters expose `connect()`, `disconnect()`, and `is_connected()`. The latter verifies backend reachability with a cached health probe (default TTL: 1 second). Subclasses may override `health_check_ttl_seconds`.
+
 ## Optional dependencies
 
 Repository **interfaces** import with the base package. **Adapters** require the matching extra; importing an adapter without its extra raises `ImportError` with install instructions.

python_repositories/adapters/minio_adapter.py

@@ -2,9 +2,10 @@
 
 from __future__ import annotations
 import os
+import structlog
+import time
 from io import BytesIO
 from typing import Self
-import structlog
 from python_utils import check_env
 
 from python_repositories.interfaces import (
@@ -34,6 +35,7 @@ class MinioAdapter(
     secret_key_env_var_name: str = "MINIO_SECRET_KEY"
     bucket_env_var_name: str = "MINIO_BUCKET"
     chunk_size: int = 5 * 2**20  # 5 MiB
+    health_check_ttl_seconds: float = 1.0
 
     def __init__(self) -> None:
         # Setup logger
@@ -52,6 +54,8 @@ class MinioAdapter(
         # Prepare internal variables
         self._client: minio.Minio | None = None
         self._bucket_name: str | None = None
+        self._health_check_at: float | None = None
+        self._health_check_ok: bool = False
 
     def __enter__(self) -> Self:
         """Enter the context."""
@@ -75,10 +79,11 @@ class MinioAdapter(
 
     def connect(self) -> None:
         """Connect to the Minio server."""
-        # Stop if already connected
-        if self.is_connected:
+        if self._client is not None and self.is_connected():
             self.logger.info("Already connected to Minio")
             return
+        if self._client is not None:
+            self.disconnect()
         # Prepare arguments
         endpoint = str(os.getenv(self.endpoint_env_var_name))
         access_key = str(os.getenv(self.access_key_env_var_name))
@@ -103,6 +108,7 @@ class MinioAdapter(
         # Persist information
         self._client = client
         self._bucket_name = bucket
+        self._invalidate_health_cache()
 
     def disconnect(self) -> None:
         """Disconnect from the Minio server."""
@@ -111,13 +117,36 @@ class MinioAdapter(
         # Reset client
         self._client = None
         self._bucket_name = None
+        self._invalidate_health_cache()
+
+    def _invalidate_health_cache(self) -> None:
+        self._health_check_at = None
+        self._health_check_ok = False
+
+    def _probe_connection(self) -> bool:
+        assert self._client is not None and self._bucket_name is not None
+        try:
+            return bool(self._client.bucket_exists(self._bucket_name))
+        except Exception:  # pylint: disable=broad-except
+            return False
 
-    @property
     def is_connected(self) -> bool:
-        """Check if connected to Minio server."""
-        res = self._client is not None
-        self.logger.debug(res)
-        return res
+        """Check if connected to the Minio server."""
+        if self._client is None or self._bucket_name is None:
+            return False
+        now = time.monotonic()
+        if self._health_check_at is not None:
+            seconds_since_last_health_check = now - self._health_check_at
+            cache_is_fresh = (
+                seconds_since_last_health_check < self.health_check_ttl_seconds
+            )
+            if cache_is_fresh:
+                return self._health_check_ok
+        result = self._probe_connection()
+        self._health_check_at = now
+        self._health_check_ok = result
+        self.logger.debug("Connection status", connected=result)
+        return result
 
     def put(
         self,
@@ -134,8 +163,9 @@ class MinioAdapter(
         if not isinstance(content_type, str) or len(content_type) == 0:
             raise ValueError("content_type must be a non-empty string")
         # Check connection
-        if self._client is None or self._bucket_name is None or not self.is_connected:
+        if not self.is_connected():
             raise ConnectionError("Not connected to Minio")
+        assert self._client is not None and self._bucket_name is not None
         # Prepare buffer for reading
         num_bytes = data.getbuffer().nbytes
         data.seek(0)
@@ -159,8 +189,9 @@ class MinioAdapter(
         if not isinstance(object_name, str) or len(object_name) == 0:
             raise ValueError("object_name must be a non-empty string")
         # Check connection
-        if self._client is None or self._bucket_name is None or not self.is_connected:
+        if not self.is_connected():
             raise ConnectionError("Not connected to Minio")
+        assert self._client is not None and self._bucket_name is not None
         # Get data from bucket
         # N.B. bucket name is set when connecting
         try:
@@ -194,8 +225,9 @@ class MinioAdapter(
         if not isinstance(object_name, str) or len(object_name) == 0:
             raise ValueError("object_name must be a non-empty string")
         # Check connection
-        if self._client is None or self._bucket_name is None or not self.is_connected:
+        if not self.is_connected():
             raise ConnectionError("Not connected to Minio")
+        assert self._client is not None and self._bucket_name is not None
         # Delete object from bucket
         # N.B. bucket name is set when connecting
         self._client.remove_object(
@@ -213,8 +245,9 @@ class MinioAdapter(
             raise ValueError("prefix must be a string")
         # Check connection
         # N.B. bucket name is set when connecting
-        if self._client is None or self._bucket_name is None or not self.is_connected:
+        if not self.is_connected():
             raise ConnectionError("Not connected to Minio")
+        assert self._client is not None and self._bucket_name is not None
         # List objects in bucket
         objects = self._client.list_objects(
             bucket_name=self._bucket_name,

python_repositories/adapters/redis_adapter.py

@@ -4,6 +4,7 @@ from __future__ import annotations
 from typing import Self, cast
 import os
 import structlog
+import time
 
 from python_utils import check_env
 
@@ -33,6 +34,7 @@ class RedisAdapter(
     uri_env_var_name: str = "REDIS_URI"
     path: str = "."  # JSON root path, updated in __init__
     encoding: str = "UTF-8"
+    health_check_ttl_seconds: float = 1.0
 
     def __init__(self) -> None:
         # Setup logger
@@ -44,6 +46,8 @@ class RedisAdapter(
         # Prepare internal variables
         self._client: redis.Redis | None = None
         self.path: str = RedisPath.root_path()
+        self._health_check_at: float | None = None
+        self._health_check_ok: bool = False
 
     def __enter__(self) -> Self:
         """Enter the context."""
@@ -67,6 +71,10 @@ class RedisAdapter(
 
     def connect(self) -> None:
         """Connect to the Redis server."""
+        if self._client is not None:
+            self._client.close()
+            self._client = None
+            self._invalidate_health_cache()
         # Prepare arguments
         uri = str(os.getenv(self.uri_env_var_name))
         # Connect client
@@ -81,6 +89,7 @@ class RedisAdapter(
             raise ConnectionError(f"Could not connect to Redis at {uri}") from exc
         # Persist client
         self._client = client
+        self._invalidate_health_cache()
 
     def disconnect(self) -> None:
         """Disconnect from the Redis server."""
@@ -89,13 +98,36 @@ class RedisAdapter(
             self._client.close()
         # Reset client
         self._client = None
+        self._invalidate_health_cache()
+
+    def _invalidate_health_cache(self) -> None:
+        self._health_check_at = None
+        self._health_check_ok = False
+
+    def _probe_connection(self) -> bool:
+        assert self._client is not None
+        try:
+            return bool(self._client.ping())
+        except (redis.ConnectionError, redis.TimeoutError):
+            return False
 
-    @property
     def is_connected(self) -> bool:
-        """Check if connected to Redis server."""
-        res = self._client is not None
-        self.logger.debug(res)
-        return res
+        """Check if connected to the Redis server."""
+        if self._client is None:
+            return False
+        now = time.monotonic()
+        if self._health_check_at is not None:
+            seconds_since_last_health_check = now - self._health_check_at
+            cache_is_fresh = (
+                seconds_since_last_health_check < self.health_check_ttl_seconds
+            )
+            if cache_is_fresh:
+                return self._health_check_ok
+        result = self._probe_connection()
+        self._health_check_at = now
+        self._health_check_ok = result
+        self.logger.debug("Connection status", connected=result)
+        return result
 
     def set(self, key: str, data: dict) -> None:
         """Set a JSON object in Redis."""
@@ -105,8 +137,9 @@ class RedisAdapter(
         if not isinstance(data, dict) or len(data) == 0:
             raise ValueError("Data must be a non-empty dictionary")
         # Check connection
-        if self._client is None or not self.is_connected:
+        if not self.is_connected():
             raise ConnectionError("Not connected to Redis")
+        assert self._client is not None
         # Set data
         self._client.json().set(key, self.path, data)
         self.logger.debug(f"Set {key} to {data}")
@@ -117,8 +150,9 @@ class RedisAdapter(
         if not isinstance(key, str) or len(key) == 0:
             raise ValueError("Key must be a non-empty string")
         # Check connection
-        if self._client is None or not self.is_connected:
+        if not self.is_connected():
             raise ConnectionError("Not connected to Redis")
+        assert self._client is not None
         # Get data
         data = cast(
             dict | None,
@@ -133,8 +167,9 @@ class RedisAdapter(
         if not isinstance(key, str) or len(key) == 0:
             raise ValueError("Key must be a non-empty string")
         # Check connection
-        if self._client is None or not self.is_connected:
+        if not self.is_connected():
             raise ConnectionError("Not connected to Redis")
+        assert self._client is not None
         # Delete data
         self._client.json().delete(key)
         self.logger.debug(f"Deleted {key}")
@@ -145,8 +180,9 @@ class RedisAdapter(
         if not isinstance(pattern, str) or len(pattern) == 0:
             raise ValueError("Pattern must be a non-empty string")
         # Check connection
-        if self._client is None or not self.is_connected:
+        if not self.is_connected():
             raise ConnectionError("Not connected to Redis")
+        assert self._client is not None
         # List keys
         keys_raw = cast(
             list[bytes],

python_repositories/interfaces/connection_aware_interface.py

@@ -16,8 +16,10 @@ class ConnectionAwareInterface(ABC):
         """Disconnect from resource."""
         ...
 
-    @property
     @abstractmethod
     def is_connected(self) -> bool:
-        """Check if connected to resource."""
+        """Return whether the adapter has an active, reachable connection.
+
+        Implementations may perform a cached network probe to verify liveness.
+        """
         ...

tests/integration/connection_aware_interface_test.py

@@ -15,7 +15,6 @@ def test_instantiation_fails_when_connect_not_implemented() -> None:
         def disconnect(self) -> None:
             pass
 
-        @property
         def is_connected(self) -> bool:
             return False
 
@@ -32,7 +31,6 @@ def test_instantiation_fails_when_disconnect_not_implemented() -> None:
         def connect(self) -> None:
             pass
 
-        @property
         def is_connected(self) -> bool:
             return False
 

tests/integration/minio_adapter_test.py

@@ -115,7 +115,7 @@ def test_should_have_logger_when_instantiated() -> None:
 def test_should_not_be_connected_when_instantiated() -> None:
     """Test that the MinioAdapter is not connected when instantiated."""
     adapter = MinioAdapter()
-    assert not adapter.is_connected
+    assert not adapter.is_connected()
 
 
 def test_should_log_info_when_already_connected(
@@ -137,7 +137,7 @@ def test_should_raise_connection_error_when_unable_to_connect(
     adapter = MinioAdapter()
     with pytest.raises(ConnectionError):
         adapter.connect()
-    assert not adapter.is_connected
+    assert not adapter.is_connected()
 
 
 def test_should_log_info_when_creating_expected_bucket(
@@ -163,7 +163,7 @@ def test_should_log_error_on_exception_during_exit(
     """Test that the MinioAdapter logs an error if an exception occurs during __exit__."""
     try:
         with MinioAdapter() as adapter:
-            assert adapter.is_connected
+            assert adapter.is_connected()
             raise ValueError("Simulated error")
     except ValueError:
         pass  # Expected

tests/integration/redis_adapter_test.py

@@ -9,7 +9,7 @@ from python_repositories.interfaces import JsonRepositoryInterface
 
 
 @pytest.fixture(scope="module")
-def data() -> Generator[dict[str, str]]:
+def data() -> Generator[dict[str, str], None, None]:
     """Provide a sample data dictionary for tests."""
     yield {"foo": "bar"}
 
@@ -18,7 +18,7 @@ def data() -> Generator[dict[str, str]]:
 def data_in_redis(
     raw_redis_client: redis.Redis,
     data: dict[str, str],
-) -> Generator[tuple[str, dict[str, str]]]:
+) -> Generator[tuple[str, dict[str, str]], None, None]:
     """Fixture to set up a known value in Redis before each test."""
     key = "test_key"
     path = RedisPath.root_path()
@@ -31,7 +31,7 @@ def data_in_redis(
 
 
 @pytest.fixture(scope="module")
-def redis_adapter(redis_container: str) -> Generator[RedisAdapter]:
+def redis_adapter(redis_container: str) -> Generator[RedisAdapter, None, None]:
     """Fixture to provide a connected RedisAdapter instance."""
     adapter = RedisAdapter()
     adapter.connect()
@@ -63,7 +63,7 @@ def test_should_not_be_connected_when_instantiated(redis_container: str) -> None
     """Test that the RedisAdapter is not connected when instantiated."""
     adapter = RedisAdapter()
     assert adapter._client is None
-    assert not adapter.is_connected
+    assert not adapter.is_connected()
 
 
 def test_should_raise_connection_error_when_unable_to_connect(
@@ -77,7 +77,7 @@ def test_should_raise_connection_error_when_unable_to_connect(
     with pytest.raises(ConnectionError):
         adapter.connect()
     assert adapter._client is None
-    assert not adapter.is_connected
+    assert not adapter.is_connected()
 
 
 def test_connect_raises_connection_error_when_unable_to_ping(
@@ -109,7 +109,7 @@ def test_should_log_error_on_exception_during_exit(
     """Test that the RedisAdapter logs an error when an exception occurs during context exit."""
     try:
         with RedisAdapter() as adapter:
-            assert adapter.is_connected
+            assert adapter.is_connected()
             raise ValueError("Simulated error")
     except ValueError:
         pass  # Expected

tests/unit/connection_health_test.py

@@ -0,0 +1,184 @@
+"""Tests for TTL-cached connection health checks on adapters."""
+
+from __future__ import annotations
+
+from unittest.mock import MagicMock, patch
+
+import pytest
+import redis
+
+from python_repositories.adapters.minio_adapter import MinioAdapter
+from python_repositories.adapters.redis_adapter import RedisAdapter
+
+
+@pytest.fixture
+def redis_adapter(monkeypatch: pytest.MonkeyPatch) -> RedisAdapter:
+    monkeypatch.setenv("REDIS_URI", "redis://localhost:6379")
+    return RedisAdapter()
+
+
+@pytest.fixture
+def minio_adapter(monkeypatch: pytest.MonkeyPatch) -> MinioAdapter:
+    monkeypatch.setenv("MINIO_ENDPOINT", "localhost:9000")
+    monkeypatch.setenv("MINIO_ACCESS_KEY", "minioadmin")
+    monkeypatch.setenv("MINIO_SECRET_KEY", "minioadmin")
+    monkeypatch.setenv("MINIO_BUCKET", "test-bucket")
+    return MinioAdapter()
+
+
+class TestRedisConnectionHealth:
+    def test_not_connected_when_no_client(self, redis_adapter: RedisAdapter) -> None:
+        assert not redis_adapter.is_connected()
+
+    def test_connected_when_probe_succeeds(self, redis_adapter: RedisAdapter) -> None:
+        mock_client = MagicMock(spec=redis.Redis)
+        mock_client.ping.return_value = True
+        redis_adapter._client = mock_client
+
+        assert redis_adapter.is_connected()
+        mock_client.ping.assert_called_once()
+
+    def test_stale_connection_when_probe_fails(
+        self, redis_adapter: RedisAdapter
+    ) -> None:
+        mock_client = MagicMock(spec=redis.Redis)
+        mock_client.ping.side_effect = redis.ConnectionError("connection lost")
+        redis_adapter._client = mock_client
+
+        assert not redis_adapter.is_connected()
+
+    def test_cache_hit_avoids_second_probe(self, redis_adapter: RedisAdapter) -> None:
+        mock_client = MagicMock(spec=redis.Redis)
+        mock_client.ping.return_value = True
+        redis_adapter._client = mock_client
+
+        with patch(
+            "python_repositories.adapters.redis_adapter.time.monotonic",
+            return_value=100.0,
+        ):
+            assert redis_adapter.is_connected()
+            assert redis_adapter.is_connected()
+
+        mock_client.ping.assert_called_once()
+
+    def test_cache_miss_runs_probe_again(self, redis_adapter: RedisAdapter) -> None:
+        mock_client = MagicMock(spec=redis.Redis)
+        mock_client.ping.return_value = True
+        redis_adapter._client = mock_client
+
+        with patch(
+            "python_repositories.adapters.redis_adapter.time.monotonic",
+            side_effect=[100.0, 102.0],
+        ):
+            assert redis_adapter.is_connected()
+            assert redis_adapter.is_connected()
+
+        assert mock_client.ping.call_count == 2
+
+    def test_disconnect_clears_cache(self, redis_adapter: RedisAdapter) -> None:
+        mock_client = MagicMock(spec=redis.Redis)
+        mock_client.ping.return_value = True
+        redis_adapter._client = mock_client
+
+        with patch(
+            "python_repositories.adapters.redis_adapter.time.monotonic",
+            return_value=100.0,
+        ):
+            assert redis_adapter.is_connected()
+
+        redis_adapter.disconnect()
+        redis_adapter._client = mock_client
+
+        with patch(
+            "python_repositories.adapters.redis_adapter.time.monotonic",
+            return_value=100.0,
+        ):
+            assert redis_adapter.is_connected()
+
+        assert mock_client.ping.call_count == 2
+
+
+class TestMinioConnectionHealth:
+    def test_not_connected_when_no_client(self, minio_adapter: MinioAdapter) -> None:
+        assert not minio_adapter.is_connected()
+
+    def test_not_connected_when_bucket_name_missing(
+        self, minio_adapter: MinioAdapter
+    ) -> None:
+        minio_adapter._client = MagicMock()
+        minio_adapter._bucket_name = None
+
+        assert not minio_adapter.is_connected()
+
+    def test_connected_when_probe_succeeds(self, minio_adapter: MinioAdapter) -> None:
+        mock_client = MagicMock()
+        mock_client.bucket_exists.return_value = True
+        minio_adapter._client = mock_client
+        minio_adapter._bucket_name = "test-bucket"
+
+        assert minio_adapter.is_connected()
+        mock_client.bucket_exists.assert_called_once_with("test-bucket")
+
+    def test_stale_connection_when_probe_fails(
+        self, minio_adapter: MinioAdapter
+    ) -> None:
+        mock_client = MagicMock()
+        mock_client.bucket_exists.side_effect = Exception("connection lost")
+        minio_adapter._client = mock_client
+        minio_adapter._bucket_name = "test-bucket"
+
+        assert not minio_adapter.is_connected()
+
+    def test_cache_hit_avoids_second_probe(self, minio_adapter: MinioAdapter) -> None:
+        mock_client = MagicMock()
+        mock_client.bucket_exists.return_value = True
+        minio_adapter._client = mock_client
+        minio_adapter._bucket_name = "test-bucket"
+
+        with patch(
+            "python_repositories.adapters.minio_adapter.time.monotonic",
+            return_value=100.0,
+        ):
+            assert minio_adapter.is_connected()
+            assert minio_adapter.is_connected()
+
+        mock_client.bucket_exists.assert_called_once()
+
+    def test_cache_miss_runs_probe_again(self, minio_adapter: MinioAdapter) -> None:
+        mock_client = MagicMock()
+        mock_client.bucket_exists.return_value = True
+        minio_adapter._client = mock_client
+        minio_adapter._bucket_name = "test-bucket"
+
+        with patch(
+            "python_repositories.adapters.minio_adapter.time.monotonic",
+            side_effect=[100.0, 102.0],
+        ):
+            assert minio_adapter.is_connected()
+            assert minio_adapter.is_connected()
+
+        assert mock_client.bucket_exists.call_count == 2
+
+    def test_disconnect_clears_cache(self, minio_adapter: MinioAdapter) -> None:
+        mock_client = MagicMock()
+        mock_client.bucket_exists.return_value = True
+        minio_adapter._client = mock_client
+        minio_adapter._bucket_name = "test-bucket"
+
+        with patch(
+            "python_repositories.adapters.minio_adapter.time.monotonic",
+            return_value=100.0,
+        ):
+            assert minio_adapter.is_connected()
+
+        minio_adapter.disconnect()
+        minio_adapter._client = mock_client
+        minio_adapter._bucket_name = "test-bucket"
+
+        with patch(
+            "python_repositories.adapters.minio_adapter.time.monotonic",
+            return_value=100.0,
+        ):
+            assert minio_adapter.is_connected()
+
+        assert mock_client.bucket_exists.call_count == 2

uv.lock

@@ -1053,7 +1053,7 @@ wheels = [
 
 [[package]]
 name = "python-repositories"
-version = "0.3.1"
+version = "0.3.2"
 source = { editable = "." }
 dependencies = [
     { name = "python-utils" },