Add artifcact_location arg to MLFlow logger (#6677)

* Add artifcact_location arg to MLFlow logger

* Add CHANGELOG URL

* Update test

Author: ethanwharris

CHANGELOG.md

@@ -67,6 +67,9 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
 - Added support for `precision=64`, enabling training with double precision ([#6595](https://github.com/PyTorchLightning/pytorch-lightning/pull/6595))
 
 
+- Added `artifact_location` argument to `MLFlowLogger` which will be passed to the `MlflowClient.create_experiment` call ([#6677](https://github.com/PyTorchLightning/pytorch-lightning/pull/6677))
+
+
 ### Changed
 
 - Renamed `pytorch_lightning.callbacks.swa` to `pytorch_lightning.callbacks.stochastic_weight_avg` ([#6259](https://github.com/PyTorchLightning/pytorch-lightning/pull/6259))

pytorch_lightning/loggers/mlflow.py

@@ -78,6 +78,8 @@ def any_lightning_module_function_or_hook(self):
             Defaults to `./mlflow` if `tracking_uri` is not provided.
             Has no effect if `tracking_uri` is provided.
         prefix: A string to put at the beginning of metric keys.
+        artifact_location: The location to store run artifacts. If not provided, the server picks an appropriate
+            default.
 
     Raises:
         ImportError:
@@ -93,6 +95,7 @@ def __init__(
         tags: Optional[Dict[str, Any]] = None,
         save_dir: Optional[str] = './mlruns',
         prefix: str = '',
+        artifact_location: Optional[str] = None,
     ):
         if mlflow is None:
             raise ImportError(
@@ -109,6 +112,8 @@ def __init__(
         self._run_id = None
         self.tags = tags
         self._prefix = prefix
+        self._artifact_location = artifact_location
+
         self._mlflow_client = MlflowClient(tracking_uri)
 
     @property
@@ -129,7 +134,10 @@ def experiment(self) -> MlflowClient:
                 self._experiment_id = expt.experiment_id
             else:
                 log.warning(f'Experiment with name {self._experiment_name} not found. Creating it.')
-                self._experiment_id = self._mlflow_client.create_experiment(name=self._experiment_name)
+                self._experiment_id = self._mlflow_client.create_experiment(
+                    name=self._experiment_name,
+                    artifact_location=self._artifact_location,
+                )
 
         if self._run_id is None:
             run = self._mlflow_client.create_run(experiment_id=self._experiment_id, tags=self.tags)

tests/loggers/test_mlflow.py

@@ -199,3 +199,31 @@ def test_mlflow_logger_with_long_param_value(client, mlflow, tmpdir):
 
     with pytest.warns(RuntimeWarning, match=f'Discard {key}={value}'):
         logger.log_hyperparams(params)
+
+
+@mock.patch('pytorch_lightning.loggers.mlflow.time')
+@mock.patch('pytorch_lightning.loggers.mlflow.mlflow')
+@mock.patch('pytorch_lightning.loggers.mlflow.MlflowClient')
+def test_mlflow_logger_experiment_calls(client, mlflow, time, tmpdir):
+    """
+    Test that the logger calls methods on the mlflow experiment correctly.
+    """
+    time.return_value = 1
+
+    logger = MLFlowLogger('test', save_dir=tmpdir, artifact_location='my_artifact_location')
+    logger._mlflow_client.get_experiment_by_name.return_value = None
+
+    params = {'test': 'test_param'}
+    logger.log_hyperparams(params)
+
+    logger.experiment.log_param.assert_called_once_with(logger.run_id, 'test', 'test_param')
+
+    metrics = {'some_metric': 10}
+    logger.log_metrics(metrics)
+
+    logger.experiment.log_metric.assert_called_once_with(logger.run_id, 'some_metric', 10, 1000, None)
+
+    logger._mlflow_client.create_experiment.assert_called_once_with(
+        name='test',
+        artifact_location='my_artifact_location',
+    )