RedisCache only accepts values that can be pickled

[codenprogressive]

Bug Description

Enable Redis cache LANGFLOW_CACHE_TYPE=redis. The flow contains one agent component and it uses gemini-3.5-flash as a model. see below image:

when running the flow it fails to build. see the whole log:

RedisCache only accepts values that can be pickled. 

Traceback (most recent call last):
  File "/usr/local/lib/python3.14/pickle.py", line 347, in whichmodule
    if _getattribute(module, dotted_path) is obj:
       ~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.14/pickle.py", line 317, in _getattribute
    obj = getattr(obj, subpath)
AttributeError: module 'lfx.io.schema' has no attribute 'InputSchema'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/langflow_install_workspace/langflow/src/backend/base/langflow/services/cache/service.py", line 282, in set
    if pickled := dill.dumps(value, recurse=True):
                  ~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^
  File "/langflow_install_workspace/langflow/.venv/lib/python3.14/site-packages/dill/_dill.py", line 289, in dumps
    dump(obj, file, protocol, byref, fmode, recurse, **kwds)#, strictio)
    ~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/langflow_install_workspace/langflow/.venv/lib/python3.14/site-packages/dill/_dill.py", line 261, in dump
    Pickler(file, protocol, **_kwds).dump(obj)
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^
  File "/langflow_install_workspace/langflow/.venv/lib/python3.14/site-packages/dill/_dill.py", line 429, in dump
    StockPickler.dump(self, obj)
    ~~~~~~~~~~~~~~~~~^^^^^^^^^^^
  File "/usr/local/lib/python3.14/pickle.py", line 498, in dump
    self.save(obj)
    ~~~~~~~~~^^^^^
  File "/langflow_install_workspace/langflow/.venv/lib/python3.14/site-packages/dill/_dill.py", line 423, in save
    StockPickler.save(self, obj, save_persistent_id)
    ~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.14/pickle.py", line 572, in save
    f(self, obj)  # Call unbound method with explicit self
    ~^^^^^^^^^^^
  File "/langflow_install_workspace/langflow/.venv/lib/python3.14/site-packages/dill/_dill.py", line 1266, in save_module_dict
    StockPickler.save_dict(pickler, obj)
    ~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.14/pickle.py", line 1058, in save_dict
    self._batch_setitems(obj.items(), obj)
    ~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.14/pickle.py", line 1084, in _batch_setitems
    save(v)
    ~~~~^^^
  File "/langflow_install_workspace/langflow/.venv/lib/python3.14/site-packages/dill/_dill.py", line 423, in save
    StockPickler.save(self, obj, save_persistent_id)
    ~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.14/pickle.py", line 572, in save
    f(self, obj)  # Call unbound method with explicit self
    ~^^^^^^^^^^^
  File "/langflow_install_workspace/langflow/.venv/lib/python3.14/site-packages/dill/_dill.py", line 1266, in save_module_dict
    StockPickler.save_dict(pickler, obj)
    ~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.14/pickle.py", line 1058, in save_dict
    self._batch_setitems(obj.items(), obj)
    ~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.14/pickle.py", line 1084, in _batch_setitems
    save(v)
    ~~~~^^^
  File "/langflow_install_workspace/langflow/.venv/lib/python3.14/site-packages/dill/_dill.py", line 423, in save
    StockPickler.save(self, obj, save_persistent_id)
    ~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.14/pickle.py", line 572, in save
    f(self, obj)  # Call unbound method with explicit self
    ~^^^^^^^^^^^
  File "/langflow_install_workspace/langflow/.venv/lib/python3.14/site-packages/dill/_dill.py", line 1266, in save_module_dict
    StockPickler.save_dict(pickler, obj)
    ~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.14/pickle.py", line 1058, in save_dict
    self._batch_setitems(obj.items(), obj)
    ~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.14/pickle.py", line 1084, in _batch_setitems
    save(v)
    ~~~~^^^
  File "/langflow_install_workspace/langflow/.venv/lib/python3.14/site-packages/dill/_dill.py", line 423, in save
    StockPickler.save(self, obj, save_persistent_id)
    ~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.14/pickle.py", line 572, in save
    f(self, obj)  # Call unbound method with explicit self
    ~^^^^^^^^^^^
  File "/usr/local/lib/python3.14/pickle.py", line 1009, in save_list
    self._batch_appends(obj, obj)
    ~~~~~~~~~~~~~~~~~~~^^^^^^^^^^
  File "/usr/local/lib/python3.14/pickle.py", line 1037, in _batch_appends
    save(x)
    ~~~~^^^
  File "/langflow_install_workspace/langflow/.venv/lib/python3.14/site-packages/dill/_dill.py", line 423, in save
    StockPickler.save(self, obj, save_persistent_id)
    ~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.14/pickle.py", line 615, in save
    self.save_reduce(obj=obj, *rv)
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.14/pickle.py", line 761, in save_reduce
    save(state)
    ~~~~^^^^^^^
  File "/langflow_install_workspace/langflow/.venv/lib/python3.14/site-packages/dill/_dill.py", line 423, in save
    StockPickler.save(self, obj, save_persistent_id)
    ~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.14/pickle.py", line 572, in save
    f(self, obj)  # Call unbound method with explicit self
    ~^^^^^^^^^^^
  File "/langflow_install_workspace/langflow/.venv/lib/python3.14/site-packages/dill/_dill.py", line 1266, in save_module_dict
    StockPickler.save_dict(pickler, obj)
    ~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.14/pickle.py", line 1058, in save_dict
    self._batch_setitems(obj.items(), obj)
    ~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.14/pickle.py", line 1084, in _batch_setitems
    save(v)
    ~~~~^^^
  File "/langflow_install_workspace/langflow/.venv/lib/python3.14/site-packages/dill/_dill.py", line 423, in save
    StockPickler.save(self, obj, save_persistent_id)
    ~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^...

I noticed similar error but different error log when using Language Model component and select gemini-3.5-flash as a model.

when running the flow it fails to build. see the whole log:

cannot pickle 'SSLContext' object

Traceback (most recent call last):
  File "/langflow_install_workspace/langflow/src/backend/base/langflow/api/build.py", line 464, in _build_vertex
    vertex_build_result = await graph.build_vertex(
                          ^^^^^^^^^^^^^^^^^^^^^^^^^
    ...<7 lines>...
    )
    ^
  File "/langflow_install_workspace/langflow/src/lfx/src/lfx/graph/graph/base.py", line 1708, in build_vertex
    await set_cache(key=vertex.id, data=vertex_dict)
  File "/langflow_install_workspace/langflow/src/backend/base/langflow/services/chat/service.py", line 37, in set_cache
    await self.cache_service.upsert(str(key), result_dict, lock=lock or self.async_cache_locks[key])
  File "/langflow_install_workspace/langflow/src/backend/base/langflow/services/cache/service.py", line 309, in upsert
    await self.set(key, value)
  File "/langflow_install_workspace/langflow/src/backend/base/langflow/services/cache/service.py", line 282, in set
    if pickled := dill.dumps(value, recurse=True):
                  ~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^
  File "/langflow_install_workspace/langflow/.venv/lib/python3.14/site-packages/dill/_dill.py", line 289, in dumps
    dump(obj, file, protocol, byref, fmode, recurse, **kwds)#, strictio)
    ~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/langflow_install_workspace/langflow/.venv/lib/python3.14/site-packages/dill/_dill.py", line 261, in dump
    Pickler(file, protocol, **_kwds).dump(obj)
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^
  File "/langflow_install_workspace/langflow/.venv/lib/python3.14/site-packages/dill/_dill.py", line 429, in dump
    StockPickler.dump(self, obj)
    ~~~~~~~~~~~~~~~~~^^^^^^^^^^^
  File "/usr/local/lib/python3.14/pickle.py", line 498, in dump
    self.save(obj)
    ~~~~~~~~~^^^^^
  File "/langflow_install_workspace/langflow/.venv/lib/python3.14/site-packages/dill/_dill.py", line 423, in save
    StockPickler.save(self, obj, save_persistent_id)
    ~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.14/pickle.py", line 572, in save
    f(self, obj)  # Call unbound method with explicit self
    ~^^^^^^^^^^^
  File "/langflow_install_workspace/langflow/.venv/lib/python3.14/site-packages/dill/_dill.py", line 1266, in save_module_dict
    StockPickler.save_dict(pickler, obj)
    ~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.14/pickle.py", line 1058, in save_dict
    self._batch_setitems(obj.items(), obj)
    ~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.14/pickle.py", line 1084, in _batch_setitems
    save(v)
    ~~~~^^^
  File "/langflow_install_workspace/langflow/.venv/lib/python3.14/site-packages/dill/_dill.py", line 423, in save
    StockPickler.save(self, obj, save_persistent_id)
    ~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.14/pickle.py", line 572, in save
    f(self, obj)  # Call unbound method with explicit self
    ~^^^^^^^^^^^
  File "/langflow_install_workspace/langflow/.venv/lib/python3.14/site-packages/dill/_dill.py", line 1266, in save_module_dict
    StockPickler.save_dict(pickler, obj)
    ~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.14/pickle.py", line 1058, in save_dict
    self._batch_setitems(obj.items(), obj)
    ~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.14/pickle.py", line 1084, in _batch_setitems
    save(v)
    ~~~~^^^
  File "/langflow_install_workspace/langflow/.venv/lib/python3.14/site-packages/dill/_dill.py", line 423, in save
    StockPickler.save(self, obj, save_persistent_id)
    ~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.14/pickle.py", line 572, in save
    f(self, obj)  # Call unbound method with explicit self
    ~^^^^^^^^^^^
  File "/langflow_install_workspace/langflow/.venv/lib/python3.14/site-packages/dill/_dill.py", line 1266, in save_module_dict
    StockPickler.save_dict(pickler, obj)
    ~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.14/pickle.py", line 1058, in save_dict
    self._batch_setitems(obj.items(), obj)
    ~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.14/pickle.py", line 1084, in _batch_setitems
    save(v)
    ~~~~^^^
  File "/langflow_install_workspace/langflow/.venv/lib/python3.14/site-packages/dill/_dill.py", line 423, in save
    StockPickler.save(self, obj, save_persistent_id)
    ~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.14/pickle.py", line 615, in save
    self.save_reduce(obj=obj, *rv)
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.14/pickle.py", line 761, in save_reduce
    save(state)
    ~~~~^^^^^^^
  File "/langflow_install_workspace/langflow/.venv/lib/python3.14/site-packages/dill/_dill.py", line 423, in save
    StockPickler.save(self, obj, save_persistent_id)
    ~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.14/pickle.py", line 572, in save
    f(self, obj)  # Call unbound method with explicit self
    ~^^^^^^^^^^^
  File "/langflow_install_workspace/langflow/.venv/lib/python3.14/site-packages/dill/_dill.py", line 1266, in save_module_dict
    StockPickler.save_dict(pickler, obj)
    ~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.14/pickle.py", line 1058, in save_dict
    self._batch_setitems(obj.items(), obj)
    ~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.14/pickle.py", line 1084, in _batch_setitems
    save(v)
    ~~~~^^^
  File "/langflow_install_workspace/langflow/.venv/lib/python3.14/site-packages/dill/_dill.py", line 423, in save
    StockPickler.save(self, obj, save_persistent_id)
    ~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.14/pickle.py", line 572, in save
    f(self, obj)  # Call unbound method with explicit self
    ~^^^^^^^^^^^
  File "/langflow_install_workspace/langflow/.venv/lib/python3.14/site-packages/dill/_dill.py", line 1266, in...

The following is a breakdown analysis of the logs.

The flow builds successfully, then fails when Langflow writes the vertex state to Redis cache.

Here is the chain from the logs:

1. Graph.build_vertex() builds LanguageModelComponent-H38jo
2. After build, it caches the vertex dict:

base.py Lines 1698-1708

                if set_cache is not None:
                    vertex_dict = {
                        "built": vertex.built,
                        "results": vertex.results,
                        "artifacts": vertex.artifacts,
                        "built_object": vertex.built_object,
                        "built_result": vertex.built_result,
                        "full_data": vertex.full_data,
                    }
                    await set_cache(key=vertex.id, data=vertex_dict)

3. ChatService.set_cache → RedisCache.set → dill.dumps(value, recurse=True)

service.py Lines 280-289

    async def set(self, key, value, lock=None) -> None:
        try:
            if pickled := dill.dumps(value, recurse=True):
                result = await self._client.setex(self._key(key), self.expiration_time, pickled)
                ...
        except pickle.PicklingError as exc:
            msg = "RedisCache only accepts values that can be pickled. "
            raise TypeError(msg) from exc

4. dill walks into the built LLM object: ChatGoogleGenerativeAI (langchain-google-genai 4.1.3) → google.genai API client → _async_httpx_client_args containing {'verify': <ssl.SSLContext ...>}
SSLContext (and also httpx clients, thread locks, retry objects) cannot be pickled. That is why I see the error even for a simple "hello" input — the model client is created during build, and caching that live object is what breaks.

my config uses Redis LANGFLOW_CACHE_TYPE=redis

Here is a snipet code to reproduce the issue:

import dill, ssl
from langchain_google_genai import ChatGoogleGenerativeAI
from pydantic import SecretStr

model = ChatGoogleGenerativeAI(model='gemini-2.5-flash', google_api_key=SecretStr('test-key'))
try:
    dill.dumps(model, recurse=True)
    print('pickle OK')
except Exception as e:
    print(type(e).__name__, e)

TypeError cannot pickle 'SSLContext' object

I previously reported this issue here #13171 and was closed but the fix did not address the issue.

Reproduction

1. enable Redis Cache LANGFLOW_CACHE_TYPE=redis
2. add two components: chat input and Large Model components
3. ask a question
4. error will popup

Expected behavior

If Redis does not support certain object then bypass that pickle action.

Who can help?

@andifilhohub

Operating System

Linux (debian 12)

Langflow Version

1.10.0

Python Version

3.12

Screenshot

No response

Flow File

No response

[AntonioABLima]

Thanks so much for the detailed report — the standalone reproduction, the traceback, and the root-cause analysis (the except pickle.PicklingError not catching the bare TypeError from SSLContext) made this very easy to confirm.

I've reproduced it locally and verified the issue is present on main (1.10.0) as well as the release-1.10.1 and release-1.11.0 branches: RedisCache.set only catches pickle.PicklingError, while serializing a live model client raises a plain TypeError, so the cache write crashes the whole vertex build instead of degrading gracefully.

I've filed an internal Jira ticket (LE-1621) so the eng team can evaluate it and ship a fix. We'll follow up here once there's an update.

Thanks again for taking the time to dig into this — and for noting the connection to the earlier #13171 report!