Pop kwargs to support LightningCLI (#154)

Closes #151.

As discussed in #151, LightningCLI does not support kwargs well, and assume kwargs are all passed into the superclass even though that's not necessarily the case. We do a small workaround here to pop certain values from kwargs to unblock using RayPlugin with LightningCLI until the actual issue is fixed upstream in PTL.

Author: amogkam

ray_lightning/ray_ddp.py

@@ -158,6 +158,15 @@ def __init__(self,
         self._global_rank = 0
         self._node_rank = 0
 
+        # Pop these arguments so LightningCLI doesn't complain about them being
+        # passed in twice.
+        # https://github.com/ray-project/ray_lightning/issues/151
+        # TODO(amogkam): Remove after
+        #  https://github.com/PyTorchLightning/pytorch-lightning/discussions/8561
+        #  is fixed.
+        ddp_kwargs.pop("parallel_devices", None)
+        ddp_kwargs.pop("cluster_environment", None)
+
         super().__init__(
             parallel_devices=[], cluster_environment=None, **ddp_kwargs)