notebook: improve cross-version compatibility

tensorboard/manager.py

@@ -139,10 +139,8 @@ def _info_from_string(info_string):
     A `TensorBoardInfo` value.
 
   Raises:
-    ValueError: If the provided string is not valid JSON, or if it does
-      not represent a JSON object with a "version" field whose value is
-      `tensorboard.version.VERSION`, or if it has the wrong set of
-      fields, or if at least one field is of invalid type.
+    ValueError: If the provided string is not valid JSON, or if it is
+      missing any required fields, or if any field is of incorrect type.
   """
 
   try:
@@ -151,27 +149,28 @@ def _info_from_string(info_string):
     raise ValueError("invalid JSON: %r" % (info_string,))
   if not isinstance(json_value, dict):
     raise ValueError("not a JSON object: %r" % (json_value,))
-  if json_value.get("version") != version.VERSION:
-    raise ValueError("incompatible version: %r" % (json_value,))
   expected_keys = frozenset(_TENSORBOARD_INFO_FIELDS)
   actual_keys = frozenset(json_value)
-  if expected_keys != actual_keys:
+  missing_keys = expected_keys - actual_keys
+  if missing_keys:
     raise ValueError(
-        "bad keys on TensorBoardInfo (missing: %s; extraneous: %s)"
-        % (expected_keys - actual_keys, actual_keys - expected_keys)
+        "TensorBoardInfo missing keys: %r"
+        % (sorted(missing_keys),)
     )
+  # For forward compatibility, silently ignore unknown keys.
 
   # Validate and deserialize fields.
+  fields = {}
   for key in _TENSORBOARD_INFO_FIELDS:
     field_type = _TENSORBOARD_INFO_FIELDS[key]
     if not isinstance(json_value[key], field_type.serialized_type):
       raise ValueError(
           "expected %r of type %s, but found: %r" %
           (key, field_type.serialized_type, json_value[key])
       )
-    json_value[key] = field_type.deserialize(json_value[key])
+    fields[key] = field_type.deserialize(json_value[key])
 
-  return TensorBoardInfo(**json_value)
+  return TensorBoardInfo(**fields)
 
 
 def cache_key(working_directory, arguments, configure_kwargs):
@@ -295,6 +294,9 @@ def get_all():
   contain extraneous entries if TensorBoard processes exited uncleanly
   (e.g., with SIGKILL or SIGQUIT).
 
+  Entries in the info directory that do not represent valid
+  `TensorBoardInfo` values will be silently ignored.
+
   Returns:
     A fresh list of `TensorBoardInfo` objects.
   """
@@ -315,7 +317,8 @@ def get_all():
     try:
       info = _info_from_string(contents)
     except ValueError:
-      tb_logging.get_logger().warning(
+      # Ignore unrecognized files, logging at debug only.
+      tb_logging.get_logger().debug(
           "invalid info file: %r",
           filepath,
           exc_info=True,

tensorboard/manager_test.py

@@ -111,30 +111,24 @@ def test_deserialization_rejects_missing_version(self):
     with six.assertRaisesRegex(
         self,
         ValueError,
-        "incompatible version:"):
+        re.escape("missing keys: ['version']")):
       manager._info_from_string(bad_input)
 
-  def test_deserialization_rejects_bad_version(self):
+  def test_deserialization_accepts_future_version(self):
     info = _make_info()
     json_value = json.loads(manager._info_to_string(info))
-    json_value["version"] = "not likely"
-    bad_input = json.dumps(json_value)
-    with six.assertRaisesRegex(
-        self,
-        ValueError,
-        "incompatible version:.*not likely"):
-      manager._info_from_string(bad_input)
+    json_value["version"] = "99.99.99a20991232"
+    input_ = json.dumps(json_value)
+    result = manager._info_from_string(input_)
+    self.assertEqual(result.version, "99.99.99a20991232")
 
-  def test_deserialization_rejects_extra_keys(self):
+  def test_deserialization_ignores_extra_keys(self):
     info = _make_info()
     json_value = json.loads(manager._info_to_string(info))
     json_value["unlikely"] = "story"
     bad_input = json.dumps(json_value)
-    with six.assertRaisesRegex(
-        self,
-        ValueError,
-        "bad keys on TensorBoardInfo"):
-      manager._info_from_string(bad_input)
+    result = manager._info_from_string(bad_input)
+    self.assertIsInstance(result, manager.TensorBoardInfo)
 
   def test_deserialization_rejects_missing_keys(self):
     info = _make_info()
@@ -144,7 +138,7 @@ def test_deserialization_rejects_missing_keys(self):
     with six.assertRaisesRegex(
         self,
         ValueError,
-        "bad keys on TensorBoardInfo"):
+        re.escape("missing keys: ['start_time']")):
       manager._info_from_string(bad_input)
 
   def test_deserialization_rejects_bad_types(self):
@@ -401,7 +395,7 @@ def test_get_all_ignores_bad_files(self):
     with open(os.path.join(self.info_dir, "pid-9012.info"), "w") as outfile:
       outfile.write('if a tbinfo has st_mode==0, does it make a sound?\n')
     os.chmod(os.path.join(self.info_dir, "pid-9012.info"), 0o000)
-    with mock.patch.object(tb_logging.get_logger(), "warning") as fn:
+    with mock.patch.object(tb_logging.get_logger(), "debug") as fn:
       self.assertEqual(manager.get_all(), [])
     self.assertEqual(fn.call_count, 2)  # 2 invalid, 1 unreadable (silent)