# Copyright (c) Streamlit Inc. (2018-2022) Snowflake Inc. (2022-2024)
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Runtime-related utility functions"""
from __future__ import annotations
from typing import Any
from streamlit import config
from streamlit.errors import MarkdownFormattedException, StreamlitAPIException
from streamlit.proto.ForwardMsg_pb2 import ForwardMsg
from streamlit.runtime.forward_msg_cache import populate_hash_if_needed
class MessageSizeError(MarkdownFormattedException):
"""Exception raised when a websocket message is larger than the configured limit."""
def __init__(self, failed_msg_str: Any):
msg = self._get_message(failed_msg_str)
super().__init__(msg)
def _get_message(self, failed_msg_str: Any) -> str:
# This needs to have zero indentation otherwise the markdown will render incorrectly.
return (
(
"""
**Data of size {message_size_mb:.1f} MB exceeds the message size limit of {message_size_limit_mb} MB.**
This is often caused by a large chart or dataframe. Please decrease the amount of data sent
to the browser, or increase the limit by setting the config option `server.maxMessageSize`.
[Click here to learn more about config options](https://docs.streamlit.io/library/advanced-features/configuration#set-configuration-options).
_Note that increasing the limit may lead to long loading times and large memory consumption
of the client's browser and the Streamlit server._
"""
)
.format(
message_size_mb=len(failed_msg_str) / 1e6,
message_size_limit_mb=(get_max_message_size_bytes() / 1e6),
)
.strip("\n")
)
class BadDurationStringError(StreamlitAPIException):
"""Raised when a bad duration argument string is passed."""
def __init__(self, duration: str):
MarkdownFormattedException.__init__(
self,
"TTL string doesn't look right. It should be formatted as"
f"`'1d2h34m'` or `2 days`, for example. Got: {duration}",
)
def is_cacheable_msg(msg: ForwardMsg) -> bool:
"""True if the given message qualifies for caching."""
if msg.WhichOneof("type") in {"ref_hash", "initialize"}:
# Some message types never get cached
return False
return msg.ByteSize() >= int(config.get_option("global.minCachedMessageSize"))
def serialize_forward_msg(msg: ForwardMsg) -> bytes:
"""Serialize a ForwardMsg to send to a client.
If the message is too large, it will be converted to an exception message
instead.
"""
populate_hash_if_needed(msg)
msg_str = msg.SerializeToString()
if len(msg_str) > get_max_message_size_bytes():
import streamlit.elements.exception as exception
# Overwrite the offending ForwardMsg.delta with an error to display.
# This assumes that the size limit wasn't exceeded due to metadata.
exception.marshall(msg.delta.new_element.exception, MessageSizeError(msg_str))
msg_str = msg.SerializeToString()
return msg_str
# This needs to be initialized lazily to avoid calling config.get_option() and
# thus initializing config options when this file is first imported.
_max_message_size_bytes: int | None = None
def get_max_message_size_bytes() -> int:
"""Returns the max websocket message size in bytes.
This will lazyload the value from the config and store it in the global symbol table.
"""
global _max_message_size_bytes
if _max_message_size_bytes is None:
_max_message_size_bytes = config.get_option("server.maxMessageSize") * int(1e6)
return _max_message_size_bytes