Add missing methods to logger collection (Lightning-AI#2723)

* Add missing methods to logger collection

* Update CHANGELOG.md

* Fix errors after merge

* Fix codefactor issues

* Update CHANGELOG.md

Co-authored-by: Jirka Borovec <Borda@users.noreply.github.com>

Co-authored-by: Jirka Borovec <Borda@users.noreply.github.com>

Author: ethanwharris

CHANGELOG.md

@@ -41,6 +41,8 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
 
 - Fixed TPU multi-core and Float16 ([#2632](https://github.com/PyTorchLightning/pytorch-lightning/pull/2632))
 
+- Fixed test metrics not being logged with `LoggerCollection` ([#2723](https://github.com/PyTorchLightning/pytorch-lightning/pull/2723))
+
 ## [0.8.5] - 2020-07-09
 
 ### Added

pytorch_lightning/loggers/base.py

@@ -272,24 +272,46 @@ def __init__(self, logger_iterable: Iterable[LightningLoggerBase]):
     def __getitem__(self, index: int) -> LightningLoggerBase:
         return [logger for logger in self._logger_iterable][index]
 
+    def update_agg_funcs(
+            self,
+            agg_key_funcs: Optional[Mapping[str, Callable[[Sequence[float]], float]]] = None,
+            agg_default_func: Callable[[Sequence[float]], float] = np.mean
+    ):
+        for logger in self._logger_iterable:
+            logger.update_agg_funcs(agg_key_funcs, agg_default_func)
+
     @property
     def experiment(self) -> List[Any]:
         return [logger.experiment for logger in self._logger_iterable]
 
+    def agg_and_log_metrics(self, metrics: Dict[str, float], step: Optional[int] = None):
+        for logger in self._logger_iterable:
+            logger.agg_and_log_metrics(metrics, step)
+
     def log_metrics(self, metrics: Dict[str, float], step: Optional[int] = None) -> None:
-        [logger.log_metrics(metrics, step) for logger in self._logger_iterable]
+        for logger in self._logger_iterable:
+            logger.log_metrics(metrics, step)
 
     def log_hyperparams(self, params: Union[Dict[str, Any], Namespace]) -> None:
-        [logger.log_hyperparams(params) for logger in self._logger_iterable]
+        for logger in self._logger_iterable:
+            logger.log_hyperparams(params)
 
     def save(self) -> None:
-        [logger.save() for logger in self._logger_iterable]
+        for logger in self._logger_iterable:
+            logger.save()
 
     def finalize(self, status: str) -> None:
-        [logger.finalize(status) for logger in self._logger_iterable]
+        for logger in self._logger_iterable:
+            logger.finalize(status)
 
     def close(self) -> None:
-        [logger.close() for logger in self._logger_iterable]
+        for logger in self._logger_iterable:
+            logger.close()
+
+    @property
+    def save_dir(self) -> Optional[str]:
+        # Checkpoints should be saved to default / chosen location when using multiple loggers
+        return None
 
     @property
     def name(self) -> str:

tests/loggers/test_base.py

@@ -22,6 +22,16 @@ def test_logger_collection():
     assert logger.experiment[0] == mock1.experiment
     assert logger.experiment[1] == mock2.experiment
 
+    assert logger.save_dir is None
+
+    logger.update_agg_funcs({'test': np.mean}, np.sum)
+    mock1.update_agg_funcs.assert_called_once_with({'test': np.mean}, np.sum)
+    mock2.update_agg_funcs.assert_called_once_with({'test': np.mean}, np.sum)
+
+    logger.agg_and_log_metrics({'test': 2.0}, 4)
+    mock1.agg_and_log_metrics.assert_called_once_with({'test': 2.0}, 4)
+    mock2.agg_and_log_metrics.assert_called_once_with({'test': 2.0}, 4)
+
     logger.close()
     mock1.close.assert_called_once()
     mock2.close.assert_called_once()