[tune/core] serialization debugging utility (#12142)

Co-authored-by: SangBin Cho <rkooo567@gmail.com>
Co-authored-by: Kai Fricke <kai@anyscale.com>

python/ray/cloudpickle/__init__.py

@@ -1,11 +1,47 @@
 from __future__ import absolute_import
 
+import os
+from pickle import PicklingError
 
 from ray.cloudpickle.cloudpickle import *  # noqa
 from ray.cloudpickle.cloudpickle_fast import CloudPickler, dumps, dump  # noqa
 
+
 # Conform to the convention used by python serialization libraries, which
 # expose their Pickler subclass at top-level under the  "Pickler" name.
 Pickler = CloudPickler
 
-__version__ = '1.6.0'
+__version__ = "1.6.0"
+
+
+def _warn_msg(obj, method, exc):
+    return (
+        f"{method}({str(obj)}) failed."
+        "\nTo check which non-serializable variables are captured "
+        "in scope, re-run the ray script with 'RAY_PICKLE_VERBOSE_DEBUG=1'.")
+
+
+def dump_debug(obj, *args, **kwargs):
+    try:
+        return dump(obj, *args, **kwargs)
+    except (TypeError, PicklingError) as exc:
+        if os.environ.get("RAY_PICKLE_VERBOSE_DEBUG"):
+            from ray.util.check_serialize import inspect_serializability
+            inspect_serializability(obj)
+            raise
+        else:
+            msg = _warn_msg(obj, "ray.cloudpickle.dump", exc)
+            raise type(exc)(msg)
+
+
+def dumps_debug(obj, *args, **kwargs):
+    try:
+        return dumps(obj, *args, **kwargs)
+    except (TypeError, PicklingError) as exc:
+        if os.environ.get("RAY_PICKLE_VERBOSE_DEBUG"):
+            from ray.util.check_serialize import inspect_serializability
+            inspect_serializability(obj)
+            raise
+        else:
+            msg = _warn_msg(obj, "ray.cloudpickle.dumps", exc)
+            raise type(exc)(msg)