[Feature] Add get_hooks_info() to print hooks messages (#672)

* Add test of get_hooks_info()

* Change to use original Runner for get_hook_info() test

* Change to test after_train_iter hooks for get_hook_info()

* Complement the stages list

* Add logging hooks information in Runner.__init__()

* Rearrange the stages list

* Restore the stages to tuple type

* Clean the unnecessary changes

* Replace  statement with TestCase's methods

* add test stages in method_stages_map

* change the hooks info into a f-string

* return list(trigger_stages) directly

* change keys of method_stages_map

* Fix previous changes to method_stages_map.keys

mmengine/hooks/hook.py

@@ -1,6 +1,8 @@
 # Copyright (c) OpenMMLab. All rights reserved.
 from typing import Dict, Optional, Sequence, Union
 
+from mmengine import is_method_overridden
+
 DATA_BATCH = Optional[Union[dict, tuple, list]]
 
 
@@ -11,6 +13,13 @@ class Hook:
     """
 
     priority = 'NORMAL'
+    stages = ('before_run', 'after_load_checkpoint', 'before_train',
+              'before_train_epoch', 'before_train_iter', 'after_train_iter',
+              'after_train_epoch', 'before_val', 'before_val_epoch',
+              'before_val_iter', 'after_val_iter', 'after_val_epoch',
+              'after_val', 'before_save_checkpoint', 'after_train',
+              'before_test', 'before_test_epoch', 'before_test_iter',
+              'after_test_iter', 'after_test_epoch', 'after_test', 'after_run')
 
     def before_run(self, runner) -> None:
         """All subclasses should override this method, if they need any
@@ -416,3 +425,28 @@ class Hook:
             bool: Whether current iteration is the last train iteration.
         """
         return runner.iter + 1 == runner.max_iters
+
+    def get_triggered_stages(self) -> list:
+        trigger_stages = set()
+        for stage in Hook.stages:
+            if is_method_overridden(stage, Hook, self):
+                trigger_stages.add(stage)
+
+        # some methods will be triggered in multi stages
+        # use this dict to map method to stages.
+        method_stages_map = {
+            '_before_epoch':
+            ['before_train_epoch', 'before_val_epoch', 'before_test_epoch'],
+            '_after_epoch':
+            ['after_train_epoch', 'after_val_epoch', 'after_test_epoch'],
+            '_before_iter':
+            ['before_train_iter', 'before_val_iter', 'before_test_iter'],
+            '_after_iter':
+            ['after_train_iter', 'after_val_iter', 'after_test_iter'],
+        }
+
+        for method, map_stages in method_stages_map.items():
+            if is_method_overridden(method, Hook, self):
+                trigger_stages.update(map_stages)
+
+        return list(trigger_stages)

mmengine/runner/runner.py

@@ -415,6 +415,9 @@ class Runner:
         self._hooks: List[Hook] = []
         # register hooks to `self._hooks`
         self.register_hooks(default_hooks, custom_hooks)
+        # log hooks information
+        self.logger.info(f'Hooks will be executed in the following '
+                         f'order:\n{self.get_hooks_info()}')
 
         # dump `cfg` to `work_dir`
         self.dump_config()
@@ -1576,6 +1579,29 @@ class Runner:
 
         return log_processor  # type: ignore
 
+    def get_hooks_info(self) -> str:
+        # Get hooks info in each stage
+        stage_hook_map: Dict[str, list] = {stage: [] for stage in Hook.stages}
+        for hook in self.hooks:
+            try:
+                priority = Priority(hook.priority).name  # type: ignore
+            except ValueError:
+                priority = hook.priority  # type: ignore
+            classname = hook.__class__.__name__
+            hook_info = f'({priority:<12}) {classname:<35}'
+            for trigger_stage in hook.get_triggered_stages():
+                stage_hook_map[trigger_stage].append(hook_info)
+
+        stage_hook_infos = []
+        for stage in Hook.stages:
+            hook_infos = stage_hook_map[stage]
+            if len(hook_infos) > 0:
+                info = f'{stage}:\n'
+                info += '\n'.join(hook_infos)
+                info += '\n -------------------- '
+                stage_hook_infos.append(info)
+        return '\n'.join(stage_hook_infos)
+
     def load_or_resume(self) -> None:
         """load or resume checkpoint."""
         if self._has_loaded:

tests/test_runner/test_runner.py

@@ -2330,3 +2330,19 @@ class TestRunner(TestCase):
         cfg = copy.deepcopy(self.epoch_based_cfg)
         cfg.experiment_name = 'test_build_runner2'
         assert isinstance(RUNNERS.build(cfg), Runner)
+
+    def test_get_hooks_info(self):
+        # test get_hooks_info() function
+        cfg = copy.deepcopy(self.epoch_based_cfg)
+        cfg.experiment_name = 'test_get_hooks_info_from_test_runner_py'
+        cfg.runner_type = 'Runner'
+        runner = RUNNERS.build(cfg)
+        self.assertIsInstance(runner, Runner)
+        target_str = ('after_train_iter:\n'
+                      '(VERY_HIGH   ) RuntimeInfoHook                    \n'
+                      '(NORMAL      ) IterTimerHook                      \n'
+                      '(BELOW_NORMAL) LoggerHook                         \n'
+                      '(LOW         ) ParamSchedulerHook                 \n'
+                      '(VERY_LOW    ) CheckpointHook                     \n')
+        self.assertIn(target_str, runner.get_hooks_info(),
+                      'target string is not in logged hooks information.')