[Tunix] Add backend_kwargs to MetricsLoggerOptions.

tests/sft/metrics_logger_test.py

@@ -44,7 +44,8 @@ def test_custom_backends_override_defaults(self, mock_register):
     mock_backend_instance = mock.Mock(spec=metrax_logging.LoggingBackend)
     mock_factory = mock.Mock(return_value=mock_backend_instance)
     options = metrics_logger.MetricsLoggerOptions(
-        log_dir=self.log_dir, backend_factories=[mock_factory]
+        log_dir=self.log_dir,
+        backend_kwargs={"custom_backend": [mock_factory]},
     )
 
     logger = metrics_logger.MetricsLogger(metrics_logger_options=options)
@@ -115,7 +116,8 @@ def test_options_deepcopy_safety(self):
       self.mock_backends[0].assert_called_with(log_dir=new_log_dir)
     else:
       self.mock_backends[0].assert_called_with(
-          log_dir=new_log_dir, flush_every_n_steps=100
+          log_dir=new_log_dir,
+          flush_every_n_steps=100,
       )
 
     logger1.close()
@@ -124,7 +126,7 @@ def test_options_deepcopy_safety(self):
   @mock.patch.object(jax.monitoring, "record_scalar")
   def test_log_metrics(self, mock_record_scalar):
     options = metrics_logger.MetricsLoggerOptions(
-        log_dir=self.log_dir, backend_factories=[]
+        log_dir=self.log_dir, backend_kwargs={"custom_backend": []}
     )
     logger = metrics_logger.MetricsLogger(metrics_logger_options=options)
     logger.log("test_prefix", "loss", 0.1, metrics_logger.Mode.TRAIN, 1)
@@ -145,7 +147,7 @@ def test_log_metrics(self, mock_record_scalar):
   @mock.patch.object(jax.monitoring, "record_scalar")
   def test_log_perplexity(self, mock_record_scalar):
     options = metrics_logger.MetricsLoggerOptions(
-        log_dir=self.log_dir, backend_factories=[]
+        log_dir=self.log_dir, backend_kwargs={"custom_backend": []}
     )
     logger = metrics_logger.MetricsLogger(metrics_logger_options=options)
     logger.log("test_prefix", "perplexity", 10.0, metrics_logger.Mode.EVAL, 1)
@@ -189,6 +191,43 @@ def test_raises_when_clu_backend_missing_in_internal_env(
       ):
         options.create_backends()
 
+  def test_backend_kwargs_are_passed_to_backends(self):
+    """Tests that backend_kwargs are passed to the backends initialization."""
+    mock_wandb = mock.Mock()
+    options = metrics_logger.MetricsLoggerOptions(
+        log_dir=self.log_dir,
+        backend_kwargs={
+            "wandb": {
+                "resume": "must",
+                "id": "12345",
+                "settings": mock_wandb.Settings(console="off"),
+            },
+            "tensorboard": {"flush_interval_s": 10.0},
+            "clu": {"some_arg": "value"},
+        },
+    )
+
+    # Trigger backend creation
+    _ = metrics_logger.MetricsLogger(metrics_logger_options=options)
+
+    if env_utils.is_internal_env():
+      self.mock_backends[0].assert_called_once_with(
+          log_dir=self.log_dir, **options.backend_kwargs["clu"]
+      )
+    else:
+      self.mock_backends[0].assert_called_once_with(
+          log_dir=self.log_dir,
+          flush_every_n_steps=100,
+          **options.backend_kwargs["tensorboard"],
+      )
+      self.mock_backends[1].assert_called_once_with(
+          project="tunix",
+          name="",
+          resume="must",
+          id="12345",
+          settings=mock_wandb.Settings.return_value,
+      )
+
 
 if __name__ == "__main__":
   absltest.main()

tunix/sft/metrics_logger.py

@@ -3,7 +3,7 @@
 import collections
 import dataclasses
 import enum
-from typing import Callable
+from typing import Any, Callable
 
 from absl import logging
 import jax
@@ -28,7 +28,26 @@ class MetricsLoggerOptions:
   project_name: str = "tunix"
   run_name: str = ""
   flush_every_n_steps: int = 100
-  backend_factories: list[BackendFactory] | None = None
+  # Keyword arguments for backend initialization. The key is the backend name
+  # (e.g., 'wandb', 'clu', 'tensorboard' or 'custom_backend' which uses custom
+  # LoggingBackend factories) and the value is a dictionary of
+  # keyword arguments to be passed to the backend's constructor.
+  # For example:
+  # backend_kwargs={
+  #   'wandb': {
+  #     'resume': 'must',
+  #     'id': '12345',
+  #     'project': 'my-project',
+  #     'name': 'my-run',
+  #   },
+  #   'tensorboard': {
+  #      'log_dir': '/path/to/log',
+  #      'flush_every_n_steps': 100,
+  #   }
+  # }
+  backend_kwargs: dict[str, dict[str, Any] | list[BackendFactory]] = (
+      dataclasses.field(default_factory=dict)
+  )
 
   def create_backends(self) -> list[LoggingBackend]:
     """Factory method to create a fresh set of live backends."""
@@ -37,28 +56,40 @@ def create_backends(self) -> list[LoggingBackend]:
       return []
 
     # Case 1: Override. Use user-provided factories.
-    if self.backend_factories is not None:
-      return [factory() for factory in self.backend_factories]
+    if (
+        "custom_backend" in self.backend_kwargs
+        and self.backend_kwargs["custom_backend"]
+    ):
+      return [factory() for factory in self.backend_kwargs["custom_backend"]]
 
     # Case 2: Defaults.
     active_backends = []
+    kwargs_dict = self.backend_kwargs or {}
 
     if env_utils.is_internal_env():
       if CluBackend is None:
         raise ImportError(
             "Internal environment detected, but CluBackend not available."
         )
-      active_backends.append(CluBackend(log_dir=self.log_dir))
+      clu_kwargs = kwargs_dict.get("clu", {})
+      active_backends.append(CluBackend(log_dir=self.log_dir, **clu_kwargs))
     else:
+      tb_kwargs = kwargs_dict.get("tensorboard", {})
       active_backends.append(
           TensorboardBackend(
               log_dir=self.log_dir,
               flush_every_n_steps=self.flush_every_n_steps,
+              **tb_kwargs,
           )
       )
       try:
+        wandb_kwargs = kwargs_dict.get("wandb", {})
         active_backends.append(
-            WandbBackend(project=self.project_name, name=self.run_name)
+            WandbBackend(
+                project=self.project_name,
+                name=self.run_name,
+                **wandb_kwargs,
+            )
         )
       except ImportError:
         logging.info("WandbBackend skipped: 'wandb' library not installed.")