Crate ebus_mqtt 

MQTT vocabulary for eBus.

The messages and commands the Homie state machines exchange with an MQTT client, topic filter matching, and, with alloc, the FilterLedger that tracks which subscriptions the client holds and who may remove them, the Role trait those state machines implement, and Pair, which runs two of them on one link.

The crate performs no I/O and reads no clock: time arrives as an Instant the caller supplies, received messages arrive as Messages, and work for the MQTT client leaves as Commands.

use ebus_mqtt::filter;

assert!(filter::matches("ebus/5/+/$state", "ebus/5/meter-1/$state"));
assert!(filter::matches("ebus/5/meter-1/#", "ebus/5/meter-1/power/watts"));
// A leading wildcard does not match a topic that starts with `$`.
assert!(!filter::matches("+/5/meter-1/$state", "$SYS/5/meter-1/$state"));

Features

• std (default): links std; implies alloc.
• alloc: Command, LastWill, FilterLedger, Role and Pair.

Modules

filter

Topic names and topic filters, per MQTT 3.1.1 section 4.7.

Structs

FilterLedgeralloc

Refcounts per filter string, so that the subscriptions several holders share are subscribed once and unsubscribed only when the last holder lets go.

Instant

Milliseconds on the caller’s monotonic clock.

LastWillalloc

The Last Will and Testament a client registers when it connects.

Message

A message received from the broker, borrowed from the client’s buffer.

Pairalloc

Two roles on one link.

Enums

Commandalloc

Work for the MQTT client.

Handled

Whether a role took a received message.

Link

A change in the state of the connection to the broker.

QoS

MQTT quality of service level.

Receiptalloc

A broker or client report on a command already sent, for a host that tracks delivery (a device built with TreeConfig::receipts).

Traits

Rolealloc

One protocol role on an MQTT link: a sans-IO state machine fed with link changes, messages and the caller’s time, and drained of commands.