hparams: encapsulate direct multiplexer access

tensorboard/plugins/hparams/backend_context.py

@@ -78,13 +78,51 @@ def experiment(self):
         return experiment
 
     @property
-    def multiplexer(self):
+    def _deprecated_multiplexer(self):
         return self._tb_context.multiplexer
 
+    @property
+    def multiplexer(self):
+        raise NotImplementedError("Do not read `Context.multiplexer` directly")
+
     @property
     def tb_context(self):
         return self._tb_context
 
+    def hparams_metadata(self):
+        """Reads summary metadata for all hparams time series.
+
+        Returns:
+          A dict `d` such that `d[run][tag]` is a `bytes` value with the
+          summary metadata content for the keyed time series.
+        """
+        return self._deprecated_multiplexer.PluginRunToTagToContent(
+            metadata.PLUGIN_NAME
+        )
+
+    def scalars_metadata(self):
+        """Reads summary metadata for all scalar time series.
+
+        Returns:
+          A dict `d` such that `d[run][tag]` is a `bytes` value with the
+          summary metadata content for the keyed time series.
+        """
+        return self._deprecated_multiplexer.PluginRunToTagToContent(
+            scalar_metadata.PLUGIN_NAME
+        )
+
+    def read_scalars(self, run, tag):
+        """Reads values for a given scalar time series.
+
+        Args:
+          run: String.
+          tag: String.
+
+        Returns:
+          A list of `plugin_event_accumulator.TensorEvent` values.
+        """
+        return self._deprecated_multiplexer.Tensors(run, tag)
+
     def _find_experiment_tag(self):
         """Finds the experiment associcated with the metadata.EXPERIMENT_TAG
         tag.
@@ -96,9 +134,7 @@ def _find_experiment_tag(self):
         """
         with self._experiment_from_tag_lock:
             if self._experiment_from_tag is None:
-                mapping = self.multiplexer.PluginRunToTagToContent(
-                    metadata.PLUGIN_NAME
-                )
+                mapping = self.hparams_metadata()
                 for tag_to_content in mapping.values():
                     if metadata.EXPERIMENT_TAG in tag_to_content:
                         self._experiment_from_tag = metadata.parse_experiment_plugin_data(
@@ -131,9 +167,7 @@ def _compute_hparam_infos(self):
         Returns:
           A list of api_pb2.HParamInfo messages.
         """
-        run_to_tag_to_content = self.multiplexer.PluginRunToTagToContent(
-            metadata.PLUGIN_NAME
-        )
+        run_to_tag_to_content = self.hparams_metadata()
         # Construct a dict mapping an hparam name to its list of values.
         hparams = collections.defaultdict(list)
         for tag_to_content in run_to_tag_to_content.values():
@@ -236,9 +270,7 @@ def _compute_metric_names(self):
         """
         session_runs = self._build_session_runs_set()
         metric_names_set = set()
-        run_to_tag_to_content = self.multiplexer.PluginRunToTagToContent(
-            scalar_metadata.PLUGIN_NAME
-        )
+        run_to_tag_to_content = self.scalars_metadata()
         for (run, tag_to_content) in six.iteritems(run_to_tag_to_content):
             session = _find_longest_parent_path(session_runs, run)
             if not session:
@@ -258,9 +290,7 @@ def _compute_metric_names(self):
 
     def _build_session_runs_set(self):
         result = set()
-        run_to_tag_to_content = self.multiplexer.PluginRunToTagToContent(
-            metadata.PLUGIN_NAME
-        )
+        run_to_tag_to_content = self.hparams_metadata()
         for (run, tag_to_content) in six.iteritems(run_to_tag_to_content):
             if metadata.SESSION_START_INFO_TAG in tag_to_content:
                 result.add(run)

tensorboard/plugins/hparams/list_session_groups.py

@@ -72,9 +72,7 @@ def _build_session_groups(self):
         # in the 'groups_by_name' dict. We create the SessionGroup object, if this
         # is the first session of that group we encounter.
         groups_by_name = {}
-        run_to_tag_to_content = self._context.multiplexer.PluginRunToTagToContent(
-            metadata.PLUGIN_NAME
-        )
+        run_to_tag_to_content = self._context.hparams_metadata()
         for (run, tag_to_content) in six.iteritems(run_to_tag_to_content):
             if metadata.SESSION_START_INFO_TAG not in tag_to_content:
                 continue
@@ -159,7 +157,7 @@ def _build_session_metric_values(self, session_name):
             metric_name = metric_info.name
             try:
                 metric_eval = metrics.last_metric_eval(
-                    self._context.multiplexer, session_name, metric_name
+                    self._context, session_name, metric_name
                 )
             except KeyError:
                 # It's ok if we don't find the metric in the session.

tensorboard/plugins/hparams/metrics.py

@@ -23,6 +23,7 @@
 import six
 
 from tensorboard.plugins.hparams import api_pb2
+from tensorboard.plugins.scalar import metadata as scalars_metadata
 from tensorboard.util import tensor_util
 
 
@@ -46,12 +47,11 @@ def run_tag_from_session_and_metric(session_name, metric_name):
     return run, tag
 
 
-def last_metric_eval(multiplexer, session_name, metric_name):
+def last_metric_eval(context, session_name, metric_name):
     """Returns the last evaluations of the given metric at the given session.
 
     Args:
-      multiplexer: The EventMultiplexer instance allowing access to
-          the exported summary data.
+      context: A `backend_context.Context` value.
       session_name: String. The session name for which to get the metric
           evaluations.
       metric_name: api_pb2.MetricName proto. The name of the metric to use.
@@ -68,7 +68,7 @@ def last_metric_eval(multiplexer, session_name, metric_name):
     """
     try:
         run, tag = run_tag_from_session_and_metric(session_name, metric_name)
-        tensor_events = multiplexer.Tensors(run=run, tag=tag)
+        tensor_events = context.read_scalars(run, tag)
     except KeyError as e:
         raise KeyError(
             "Can't find metric %s for session: %s. Underlying error message: %s"