Module maviola::asnc

Maviola asynchronous I/O

Synchronous API is built around MAVlink Node with AsyncApi. Upon construction, each node operates on a particular connection. The latter is owned by a node and defines underlying transport (e.g. TCP, UDP, Unix socket). Each connection spawns one or several channels. For example, TCP server creates a channel per each incoming connection. Abstractions related to channels and connections are defined in the io module.

Usage

To use asynchronous API, you have to first configure node builder using Node::asnc. For example, the following snippet will create an asynchronous TCP client:

use maviola::prelude::*;

let addr = "127.0.0.1:5600";

// Create a TCP client node
let node = Node::asnc::<V2>()
        /* define other node parameters */
        .connection(
            TcpClient::new(addr)    // Configure TCP client connection
                .unwrap()
        )
        .build().await.unwrap();

Transport

The following transports are currently available:

• TCP: TcpServer / TcpClient
• UDP: UdpServer / UdpClient
• File: FileWriter / FileReader
• Unix socket: SockServer / SockClient (only on Unix-like systems such as Linux or OS X)

Connection-level information about each transport is available as a variant of ConnectionInfo. Channel information is provided by ChannelInfo.

Events

The suggested approach for handling connection with several MAVLink devices is subscribing for Node::events. This method provides an iterator over all node events. Incoming frames are emitted as Event::Frame. Such events contain a Frame / Callback pair. The latter can be used to respond to a channel from which frame was received or broadcast it to all channels (or, alternatively, to all channels except the one which delivered the original frame).

Peers

Each node handles incoming frame and monitors MAVLink devices represented as Peer objects using MAVLink heartbeat protocol. Upon discovery of a peer, an Event::NewPeer event is emitted. When peers is lost due to missing heartbeats, then Event::PeerLost is emitted.

It is possible to get a list of active peers by Node::peers or check for peers availability using Node::has_peers.

Custom connections

It is possible to create a custom connection by implementing a ConnectionBuilder trait. For Custom connections there are reserved ConnectionDetails::Custom and ChannelDetails::Custom variants. Check for other relevant abstractions in io module.

Low-level I/O

Low-level I/O primitives are available in core::io. Most of these abstractions are re-exported from Mavio, a low-level MAVLink library which serves as a basis for Maviola.

Modules

• io
  Asynchronous I/O primitives
• marker
  Generic markers for synchronous I/O
• node
  API extensions for asynchronous MAVLink node
• prelude
  Common imports for asynchronous API
• utils
  ^⍚ Asynchronous utils