Crate ebus_discovery_tokio 

mDNS broker discovery and host advertisement for eBus on tokio.

The protocol decisions live in the sans-IO ebus_discovery crate; this crate runs them over an mDNS stack. A host makes one Mdns and uses it for its two jobs:

Job	Call
Find the site’s broker before building its MQTT options	find_broker, or list_brokers to pick from every broker seen
Find the same broker again after its address changes	reresolve
Advertise the host’s own services	advertise, then Advertiser::update and Advertiser::withdraw

The backends implement Backend: Avahi under the avahi feature, a client of avahi-daemon over D-Bus that compiles only on Linux, and mdns-sd under the mdns-sd feature, with its own responder thread and sockets. Mdns::system picks the backend at run time. Built with neither feature, Mdns::system returns Error::NoBackend; a host can still pass its own Backend to the search and advertising functions.

use ebus_discovery_tokio::ebus_discovery::{BrokerConfig, BrokerEndpoint, BrokerMode};
use ebus_discovery_tokio::{Mdns, find_broker};

let mdns = Mdns::system().await?;
let mut cfg = BrokerConfig::default();
cfg.mode = Some(BrokerMode::DiscoveryWithFallback);
cfg.url = Some(BrokerEndpoint::from_url("mqtt://broker.example:1883")?);
let broker = find_broker(&mdns, cfg).await?;
let (host, port) = (broker.connect_host().into_owned(), broker.port);

Re-exports

pub use ebus_discovery;

Structs

Advertiser

A running advertisement. Dropping it withdraws the records from the advertiser’s task.

Mdns

The mDNS backend a host holds; clones share one backend.

MdnsBrowse

A browse of an Mdns backend.

MdnsGroup

A published group of an Mdns backend.

MdnsSdOptionsmdns-sd

Options for the mdns-sd backend.

Enums

AdState

Where an advertisement stands.

Error

A discovery or advertising failure.

GroupReport

What a published Group reports.

HostName

The host name a host advertises its services under: the SRV target.

Traits

Backend

An mDNS stack: browsing and publishing.

Browse

A running browse of one service type; dropping it stops the browse.

Group

Published records under one instance name; dropping it withdraws them.

Functions

advertise

Advertise ad under host: every record under one instance name, from Advertisement::instance_names. A collision on any record withdraws them all and registers them again under the next name, -2 through -99; after that the state is AdState::Failed. A host rename rebuilds the records for the new SRV target and registers them again in place.

find_broker

Run a BrokerSearch to its result: the configured broker at once in configured-only, else the broker the search settles on, or the configured broker when discovery-with-fallback finds no match. The browses stop once the result is set. A search that finds nothing runs until the caller stops it, for instance with tokio::time::timeout.

list_brokers

Browse for window from the start and return the accepted brokers, with cfg.wanted applied, ranked (BrokerConfig::rank). Each broker appears once, under the transport earliest in BrokerConfig::accepted. The browse covers the accepted types, and every broker type when cfg.wanted is a Wanted::DeviceId, whose id another transport of the broker may carry. A configuration BrokerSearch::new rejects is an Error::Config.

reresolve

The same broker looked up again by its instance name and type, with its current addresses, after its host’s address changed. Returns once the broker is seen with an IPv4 candidate address, or with any address when its host is not a .local name; otherwise at the end of window, with the latest sighting. Ok(None) for a configured broker, for one not seen within window, and for one cfg no longer accepts.