ref: group connectors (#3472)

* ref: accelerator connector methods 3/n

* ref: accelerator connector methods 3/n

pytorch_lightning/accelerators/tpu_backend.py

@@ -13,6 +13,7 @@
 # limitations under the License.
 
 import os
+import re
 
 import torch
 import torch.multiprocessing as mp
@@ -22,6 +23,7 @@ from pytorch_lightning.core import LightningModule
 from pytorch_lightning.utilities import rank_zero_info, rank_zero_only, rank_zero_warn, AMPType
 from pytorch_lightning.utilities.exceptions import MisconfigurationException
 from pytorch_lightning.accelerators.base_backend import Accelerator
+from pytorch_lightning.utilities.cloud_io import atomic_save
 
 try:
     import torch_xla
@@ -124,7 +126,7 @@ class TPUBackend(Accelerator):
         self.__save_end_of_training_weights(model, trainer)
 
         # persist info in spawn
-        trainer.transfer_distrib_spawn_state_on_fit_end(model, mp_queue, results)
+        self.transfer_distrib_spawn_state_on_fit_end(model, mp_queue, results)
 
     def training_step(self, args):
         batch = args[0]
@@ -294,3 +296,25 @@ class TPUBackend(Accelerator):
             os.remove(path)
 
         return loaded_model
+
+    def transfer_distrib_spawn_state_on_fit_end(self, model, mp_queue, results):
+        if self.trainer.distributed_backend.lower() not in ['ddp_spawn', 'ddp_cpu', 'tpu']:
+            return
+
+        # track the best model path
+        best_model_path = None
+        if self.trainer.checkpoint_callback is not None:
+            best_model_path = self.trainer.checkpoint_callback.best_model_path
+
+        if self.trainer.global_rank == 0 and mp_queue is not None:
+            rank_zero_warn('cleaning up ddp environment...')
+            # todo, pass complete checkpoint as state dictionary
+            mp_queue.put(best_model_path)
+            mp_queue.put(results)
+
+            # save the last weights
+            last_path = None
+            if not self.trainer.testing and best_model_path is not None and len(best_model_path) > 0:
+                last_path = re.sub('.ckpt', '.tmp_end.ckpt', best_model_path)
+                atomic_save(model.state_dict(), last_path)
+            mp_queue.put(last_path)

pytorch_lightning/trainer/properties.py

@@ -1,5 +1,5 @@
 from pytorch_lightning.utilities.cloud_io import get_filesystem
-from pytorch_lightning.trainer.logger_connector import LoggerConnector
+from pytorch_lightning.trainer.connectors.logger_connector import LoggerConnector
 from pytorch_lightning.trainer.states import TrainerState
 from typing import List, Optional, Union
 from pytorch_lightning.utilities import argparse_utils
@@ -10,7 +10,7 @@ import os
 from pytorch_lightning.utilities.model_utils import is_overridden
 from pytorch_lightning.core.lightning import LightningModule
 from pytorch_lightning.callbacks import ProgressBarBase
-from pytorch_lightning.trainer.model_connector import ModelConnector
+from pytorch_lightning.trainer.connectors.model_connector import ModelConnector
 
 
 class TrainerProperties(ABC):

pytorch_lightning/trainer/trainer.py

@@ -14,10 +14,9 @@
 
 import os
 import warnings
-from typing import Any, Dict, Iterable, List, Optional, Tuple, Union
+from typing import Dict, Iterable, List, Optional, Union
 
 import torch
-import torch.distributed as torch_distrib
 from torch.utils.data import DataLoader
 
 from pytorch_lightning.callbacks import Callback, EarlyStopping, ModelCheckpoint
@@ -26,7 +25,7 @@ from pytorch_lightning.core.lightning import LightningModule
 from pytorch_lightning.core.memory import ModelSummary
 from pytorch_lightning.core.step_result import EvalResult
 from pytorch_lightning.loggers import LightningLoggerBase
-from pytorch_lightning.profiler import BaseProfiler, PassThroughProfiler, SimpleProfiler
+from pytorch_lightning.profiler import BaseProfiler
 from pytorch_lightning.trainer.callback_hook import TrainerCallbackHookMixin
 from pytorch_lightning.trainer.configuration_validator import ConfigValidator
 from pytorch_lightning.trainer.data_loading import TrainerDataLoadingMixin
@@ -37,23 +36,23 @@ from pytorch_lightning.trainer.optimizers import TrainerOptimizersMixin
 from pytorch_lightning.trainer.states import TrainerState, trainer_state
 from pytorch_lightning.trainer.training_io import TrainerIOMixin
 from pytorch_lightning.trainer.training_tricks import TrainerTrainingTricksMixin
-from pytorch_lightning.utilities import parsing, rank_zero_info, rank_zero_only, rank_zero_warn, AMPType
+from pytorch_lightning.utilities import rank_zero_warn
 from pytorch_lightning.utilities.debugging import InternalDebugger
 from pytorch_lightning.utilities.exceptions import MisconfigurationException
 from pytorch_lightning.trainer.evaluation_loop import EvaluationLoop
 from pytorch_lightning.trainer.training_loop import TrainLoop
 from pytorch_lightning.accelerators.accelerator_connector import AcceleratorConnector
-from pytorch_lightning.trainer.logger_connector import LoggerConnector
-from pytorch_lightning.trainer.optimizer_connector import OptimizerConnector
-from pytorch_lightning.trainer.training_trick_connector import TrainingTricksConnector
-from pytorch_lightning.trainer.callback_connector import CallbackConnector
-from pytorch_lightning.trainer.model_connector import ModelConnector
-from pytorch_lightning.trainer.debugging_connector import DebuggingConnector
+from pytorch_lightning.trainer.connectors.logger_connector import LoggerConnector
+from pytorch_lightning.trainer.connectors.optimizer_connector import OptimizerConnector
+from pytorch_lightning.trainer.connectors.training_trick_connector import TrainingTricksConnector
+from pytorch_lightning.trainer.connectors.callback_connector import CallbackConnector
+from pytorch_lightning.trainer.connectors.model_connector import ModelConnector
+from pytorch_lightning.trainer.connectors.debugging_connector import DebuggingConnector
 from pytorch_lightning import _logger as log
 from pytorch_lightning.tuner.tuning import Tuner
-from pytorch_lightning.trainer.precision_connector import PrecisionConnector
-from pytorch_lightning.trainer.profiler_connector import ProfilerConnector
-from pytorch_lightning.trainer.data_connector import DataConnector
+from pytorch_lightning.trainer.connectors.precision_connector import PrecisionConnector
+from pytorch_lightning.trainer.connectors.profiler_connector import ProfilerConnector
+from pytorch_lightning.trainer.connectors.data_connector import DataConnector
 from pytorch_lightning.utilities.model_utils import is_overridden
 from pytorch_lightning.trainer import docstrings
 from pytorch_lightning.trainer.properties import TrainerProperties