wandb logger 'global_step' affects other logger (#1492)

* Removed unnecessary 'global_step' from wandb logger.

* Fixed wrong step implementation in wandb and missing metric skipping in logger base.

* simplified metric check in base logger

* Added Fix Description in CHANGELOG.md

* Updated wandb logger tests.

* udpate test, step=3

* Moved Fix Description in CHANGELOG.md to unreleased.

* Update CHANGELOG.md

Co-authored-by: Adrian Wälchli <aedu.waelchli@gmail.com>
Co-authored-by: Jirka Borovec <Borda@users.noreply.github.com>

CHANGELOG.md

@@ -24,6 +24,7 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
 
 - Fixed Horovod distributed backend to set the `root_gpu` property ([#1669](https://github.com/PyTorchLightning/pytorch-lightning/pull/1669))
 
+- Fixed wandb logger `global_step` affects other loggers ([#1492](https://github.com/PyTorchLightning/pytorch-lightning/issues/1485))
 
 ## [0.7.5] - 2020-04-27
 

pytorch_lightning/loggers/base.py

@@ -125,7 +125,7 @@ class LightningLoggerBase(ABC):
         """
         agg_step, metrics_to_log = self._aggregate_metrics(metrics=metrics, step=step)
 
-        if metrics_to_log is not None:
+        if metrics_to_log:
             self.log_metrics(metrics=metrics_to_log, step=agg_step)
 
     @abstractmethod

pytorch_lightning/loggers/wandb.py

@@ -119,9 +119,7 @@ class WandbLogger(LightningLoggerBase):
 
     @rank_zero_only
     def log_metrics(self, metrics: Dict[str, float], step: Optional[int] = None) -> None:
-        if step is not None:
-            metrics['global_step'] = step
-        self.experiment.log(metrics)
+        self.experiment.log(metrics, step=step)
 
     @property
     def name(self) -> str:

tests/loggers/test_wandb.py

@@ -14,11 +14,11 @@ def test_wandb_logger(wandb):
     logger = WandbLogger(anonymous=True, offline=True)
 
     logger.log_metrics({'acc': 1.0})
-    wandb.init().log.assert_called_once_with({'acc': 1.0})
+    wandb.init().log.assert_called_once_with({'acc': 1.0}, step=None)
 
     wandb.init().log.reset_mock()
     logger.log_metrics({'acc': 1.0}, step=3)
-    wandb.init().log.assert_called_once_with({'global_step': 3, 'acc': 1.0})
+    wandb.init().log.assert_called_once_with({'acc': 1.0}, step=3)
 
     logger.log_hyperparams({'test': None})
     wandb.init().config.update.assert_called_once_with({'test': None}, allow_val_change=True)