Avoid calling pformat unless debug logging is enabled (#217)

* Avoid calling pformat unless debug logging is enabled

* add logging test

* isort

* check for debug logging

* formatting

kasa/protocol.py

@@ -90,8 +90,10 @@ async def _execute_query(self, request: str) -> Dict:
         """Execute a query on the device and wait for the response."""
         assert self.writer is not None
         assert self.reader is not None
+        debug_log = _LOGGER.isEnabledFor(logging.DEBUG)
 
-        _LOGGER.debug("> (%i) %s", len(request), request)
+        if debug_log:
+            _LOGGER.debug("> (%i) %s", len(request), request)
         self.writer.write(TPLinkSmartHomeProtocol.encrypt(request))
         await self.writer.drain()
 
@@ -101,7 +103,8 @@ async def _execute_query(self, request: str) -> Dict:
         buffer = await self.reader.readexactly(length)
         response = TPLinkSmartHomeProtocol.decrypt(buffer)
         json_payload = json.loads(response)
-        _LOGGER.debug("< (%i) %s", len(response), pf(json_payload))
+        if debug_log:
+            _LOGGER.debug("< (%i) %s", len(response), pf(json_payload))
         return json_payload
 
     async def close(self):

kasa/tests/test_protocol.py

@@ -1,4 +1,5 @@
 import json
+import logging
 import struct
 import sys
 
@@ -64,6 +65,39 @@ def aio_mock_writer(_, __):
     assert response == {"great": "success"}
 
 
+@pytest.mark.skipif(sys.version_info < (3, 8), reason="3.8 is first one with asyncmock")
+@pytest.mark.parametrize("log_level", [logging.WARNING, logging.DEBUG])
+async def test_protocol_logging(mocker, caplog, log_level):
+    caplog.set_level(log_level)
+    logging.getLogger("kasa").setLevel(log_level)
+    encrypted = TPLinkSmartHomeProtocol.encrypt('{"great":"success"}')[
+        TPLinkSmartHomeProtocol.BLOCK_SIZE :
+    ]
+
+    async def _mock_read(byte_count):
+        nonlocal encrypted
+        if byte_count == TPLinkSmartHomeProtocol.BLOCK_SIZE:
+            return struct.pack(">I", len(encrypted))
+        if byte_count == len(encrypted):
+            return encrypted
+        raise ValueError(f"No mock for {byte_count}")
+
+    def aio_mock_writer(_, __):
+        reader = mocker.patch("asyncio.StreamReader")
+        writer = mocker.patch("asyncio.StreamWriter")
+        mocker.patch.object(reader, "readexactly", _mock_read)
+        return reader, writer
+
+    protocol = TPLinkSmartHomeProtocol("127.0.0.1")
+    mocker.patch("asyncio.open_connection", side_effect=aio_mock_writer)
+    response = await protocol.query({})
+    assert response == {"great": "success"}
+    if log_level == logging.DEBUG:
+        assert "success" in caplog.text
+    else:
+        assert "success" not in caplog.text
+
+
 def test_encrypt():
     d = json.dumps({"foo": 1, "bar": 2})
     encrypted = TPLinkSmartHomeProtocol.encrypt(d)