Stream

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This page lists the Python SDK names for Streams. The doc comment of each API gives its parameters, defaults, and errors. Read them in the Python SDK API reference.

API names

Task	Python API	Dex behavior
Define a Stream and its byte capacity	Stream, with stream_capacity_bytes	Capacity and trimming
Declare it in the Flow	PersistenceSchema.of, returned from get_persistence_schema	Flow definition
Write a message from a Step	Stream.write	Write semantics
Write text chunks in batches from a Step	Stream.buffered_text	Buffer text chunks
Write a message from a Client	Client.write_stream	Write semantics
Read the next message	Client.read_stream, with the resume_token of the last message	Resumable reads
List retained messages, newest first	Client.list_stream_messages	List messages

Stream.write works in wait_for, execute, and the Flow timeout handler. An RPC handler cannot write a Stream. In a synchronous handler, Stream.write returns a StepOutput that the handler must yield. In an asynchronous handler, it enqueues the message and returns nothing.

Example

Example: examples/python/dex_examples/primitives/stream/stream_flow.py