fluvio-smartstream 0.2.0

Fluvio SmartStream WASM library

Fluvio SmartStreams

This crate provides types and macros for creating custom SmartStreams, which are WebAssembly modules that may be used to modify the behavior of Fluvio streams to consumers. The currently supported SmartStream types are filters, which may describe records to keep in or discard from a stream.

Writing SmartStreams

See the examples directory for full examples.


Create a new cargo project and add fluvio-smartstream as a dependency, along with the following Cargo.toml changes.

name = "fluvio-wasm-filter"
version = "0.1.0"
authors = ["Fluvio Contributors <team@fluvio.io>"]
edition = "2018"

crate-type = ['cdylib']

fluvio-smartstream = { path = "../../" }

Then, write your smartstream using #[smartstream(filter)] on your top-level function. Consider this the "main" function of your SmartStream.

use fluvio_smartstream::{smartstream, SimpleRecord};

pub fn my_filter(record: &SimpleRecord) -> bool {
    let value = String::from_utf8_lossy(record.value.as_ref());

This filter will keep only records whose contents contain the letter z.


This project is licensed under the Apache license.


Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in Fluvio by you, shall be licensed as Apache, without any additional terms or conditions.