Crate futures_zmq

Expand description

Futures ZMQ, bringing ZeroMQ any futures runtime.

Futures ZMQ contains wrappers around ZeroMQ Concepts with Futures. It shares an external API with tokio-zmq, but unlike tokio-zmq, futures-zmq is OS and Executor agnostic. This comes at the cost of performance, as futures-zmq relies on spinning up a separate thread for managing the ZeroMQ sockets, while tokio-zmq can avoid this issue by letting mio manage the sockets.

This crate provides Streams, Sinks, and Futures for ZeroMQ Sockets, which deal in structures caled Multiparts. Currently, a Multipart is a simple wrapper around VecDeque<zmq::Message>, but in the future this will be represented as a wrapper around VecDeque<S: zmq::Sendable> with the zmq 0.9 release.

Creating a socket

To get a new socket, you must invoke the Socket builder. The Socket Builder can output a ‘raw’ Socket, or any specific kind of socket, such as Rep, Req, etc. The result of the builder can be any compatable kind of socket, so specifiying a type is important.

Once you have a socket, if it implements StreamSocket, you can use the socket’s .stream() and .recv(), if it implements SinkSocket, you can use the socket’s .sink(usize) and .send(Multipart).

Without further ado, creating and using a socket:

extern crate zmq;
extern crate futures;
extern crate tokio;
extern crate futures_zmq;

use std::sync::Arc;

use futures::{Future, Stream};
use futures_zmq::{prelude::*, Socket, Pub, Sub, Error};

fn run() -> Result<(), Error> {
    // Create a new ZeroMQ Context. This context will be used to create all the sockets.
    let context = Arc::new(zmq::Context::new());

    // Create our two sockets using the Socket builder pattern.
    // Note that the variable is named zpub, since pub is a keyword
    let zpub = Pub::builder(Arc::clone(&context))
        .bind("tcp://*:5561")
        .build();

    let sub = Sub::builder(context)
        .bind("tcp://*:5562")
        .filter(b"")
        .build();

    // Create our simple server. This forwards messages from the Subscriber socket to the
    // Publisher socket, and prints them as they go by.
    let runner = zpub
        .join(sub)
        .and_then(|(zpub, sub)| {
            sub.stream()
                .map(|multipart| {
                    for msg in &multipart {
                        if let Some(msg) = msg.as_str() {
                            println!("Forwarding: {}", msg);
                        }
                    }
                    multipart
                })
                .forward(zpub.sink(25))
        });

    // To avoid an infinte doctest, the actual tokio::run is commented out.
    // tokio::run(runner.map(|_| ()).or_else(|e| {
    //     println!("Error: {}", e);
    // })?;
}

Re-exports

pub use self::error::Error;

Modules

async_types

error

prelude

Provide useful types and traits for working with Futures ZMQ.

Structs

Dealer

The DEALER SocketType wrapper type.

Multipart

This type is used for receiving and sending messages in Multipart groups. An application could make using this easier by implementing traits as follows:

Pair

The PAIR SocketType wrapper type.

Pub

The PUB SocketType wrapper type

Pull

The PULL SocketType wrapper type

Push

The PUSH SocketType wrapper type

RecvFuture

Rep

The REP SocketType wrapper type

Req