Add hooks building to classification task (#62)

Summary:
Pull Request resolved: fairinternal/ClassyVision#62

Add configurable hooks to classification task, note this is not yet fully hooked up since code here: https://fburl.com/diffusion/ou4nszl2 sets the hooks (will fix this once I get feedback on the approach).

Differential Revision: D19770583

fbshipit-source-id: b29c13d562c99db86f9219bfd9c603e4a9aa348f

classy_vision/tasks/classification_task.py

@@ -23,7 +23,7 @@
     recursive_copy_to_gpu,
     update_classy_state,
 )
-from classy_vision.hooks import ClassyHookFunctions
+from classy_vision.hooks import ClassyHookFunctions, build_hooks
 from classy_vision.losses import ClassyLoss, build_loss
 from classy_vision.meters import build_meters
 from classy_vision.models import ClassyModel, build_model
@@ -297,6 +297,7 @@ def from_config(cls, config: Dict[str, Any]) -> "ClassificationTask":
         amp_opt_level = config.get("amp_opt_level")
         meters = build_meters(config.get("meters", {}))
         model = build_model(config["model"])
+        hooks = build_hooks(config["hooks"])
         # put model in eval mode in case any hooks modify model states, it'll
         # be reset to train mode before training
         model.eval()
@@ -315,6 +316,7 @@ def from_config(cls, config: Dict[str, Any]) -> "ClassificationTask":
             .set_distributed_options(
                 BroadcastBuffersMode[config.get("broadcast_buffers", "DISABLED")]
             )
+            .set_hooks(hooks)
         )
         for phase_type in phase_types:
             task.set_dataset(datasets[phase_type], phase_type)