Struct rants::Client

pub struct Client { /* fields omitted */ }

The entry point to the NATS client protocol

Methods

impl Client

pub fn new(addresses: Vec<Address>) -> Self

Create a new Client with a default Connect

Arguments

• addresses - the list of addresses to try and establish a connection to a server

pub fn with_connect(addresses: Vec<Address>, connect: Connect) -> Self

Create a new Client with the provided Connect

Arguments

• addresses - the list of addresses to try and establish a connection to a server

pub async fn state<'_>(&'_ self) -> ClientState

Get the current state of the Client

pub async fn state_stream<'_>(&'_ self) -> WatchReceiver<ClientState>

Get a watch stream of Client state transitions

pub async fn info<'_>(&'_ self) -> Info

Get a the most recent Info sent from the server

pub async fn connect_mut<'_, '_>(&'_ self) -> ClientRefMut<'_, Connect>

Get a mutable reference to this Client's Connect

pub async fn addresses_mut<'_, '_>(&'_ self) -> ClientRefMut<'_, [Address]>

Get a mutable reference to the list of addresses used to try and establish a connection to a server.

pub async fn tcp_connect_timeout<'_>(&'_ self) -> Duration

Get the configured TCP connect timeout. [default = 10s]

This is the timeout of a single connect attempt. It is not the timeout of the connect future which has no internal timeout.

pub async fn set_tcp_connect_timeout<'_, '_>(
    &'_ self,
    tcp_connect_timeout: Duration
) -> &'_ Self

Set the TCP connect timeout.

pub async fn delay_generator_mut<'_, '_>(
    &'_ self
) -> ClientRefMut<'_, DelayGenerator>

Get the DelayGenerator

The default generator is generated with generate_delay_generator with the following parameters:

• connect_series_attempts_before_cool_down = 3
• connect_delay = 0s
• connect_series_delay = 5s
• cool_down = 60s

pub async fn sids<'_>(&'_ self) -> Vec<Sid>

Get a list of all currently subscribed subscription IDs

pub async fn subscription<'_, '_>(
    &'_ self,
    sid: Sid
) -> Option<ClientRef<'_, Subscription>>

Return a reference to a Subscription if the client is aware of the specified subscription ID

pub async fn send_connect<'_>(&'_ self) -> Result<()>

Send a CONNECT message to the server using the configured Connect.

Note: connect automatically sends a CONNECT message. This is only needed in the case that you want to change the connection parameters after already establishing a connection.

pub async fn connect<'_>(&'_ self)

Connect to a NATS server

This will randomly shuffle a list consisting of all explicitly specified addresses and addresses received in an INFO message's connect_urls. A randomized list of addresses is used to avoid a thundering herd. The client will continuously try to connect to each address in this list. The timeout of each connect attempt is specified by the tcp_connect_timeout. The delay between each connect attempt is specified by the delay_generator_mut.

When this future resolves, we are guaranteed to have entered the Connected state. Unless, disconnect was called.

pub async fn disconnect<'_>(&'_ self)

Disconnect from the NATS server

When this future resolves, we are guaranteed to have entered the Disconnected state.

Note: Client does not disconnect when it is Dropped. In order to avoid leaking futures, you must explicitly call disconnect.

pub async fn publish<'_, '_, '_>(
    &'_ self,
    subject: &'_ Subject,
    payload: &'_ [u8]
) -> Result<()>

Convenience wrapper around publish_with_optional_reply

pub async fn publish_with_reply<'_, '_, '_, '_>(
    &'_ self,
    subject: &'_ Subject,
    reply_to: &'_ Subject,
    payload: &'_ [u8]
) -> Result<()>

Convenience wrapper around publish_with_optional_reply

pub async fn publish_with_optional_reply<'_, '_, '_, '_>(
    &'_ self,
    subject: &'_ Subject,
    reply_to: Option<&'_ Subject>,
    payload: &'_ [u8]
) -> Result<()>

PUBlish a message

Arguments

• subject - The subject to publish to
• reply_to - The optional reply to subject
• payload - The actual contents of the message

pub async fn request<'_, '_, '_>(
    &'_ self,
    subject: &'_ Subject,
    payload: &'_ [u8]
) -> Result<Msg>

Implements the request-reply pattern

Note: This uses the old method of request reply. It creates a temporary subscription that is immediately unsubscribed from. See here for an improved implementation.

pub async fn subscribe<'_, '_>(
    &'_ self,
    subject: &'_ Subject,
    buffer: usize
) -> Result<(Sid, MpscReceiver<Msg>)>

Convenience wrapper around subscribe_with_optional_queue_group

pub async fn subscribe_with_queue_group<'_, '_, '_>(
    &'_ self,
    subject: &'_ Subject,
    queue_group: &'_ str,
    buffer: usize
) -> Result<(Sid, MpscReceiver<Msg>)>

Convenience wrapper around subscribe_with_optional_queue_group

pub async fn subscribe_with_optional_queue_group<'_, '_, '_>(
    &'_ self,
    subject: &'_ Subject,
    queue_group: Option<&'_ str>,
    buffer: usize
) -> Result<(Sid, MpscReceiver<Msg>)>

SUBscribe to a Subject

Returns the subscription ID of the newly created subscription and a channel to receive incoming messages on.

Arguments

• subject - The subject to subscribe to
• reply_to - The optional queue group to join
• buffer - The size of the underlying mpsc channel

pub async fn unsubscribe<'_>(&'_ self, sid: Sid) -> Result<()>

Convenience wrapper around unsubscribe_optional_max_msgs

pub async fn unsubscribe_with_max_msgs<'_>(
    &'_ self,
    sid: Sid,
    max_msgs: u64
) -> Result<()>

Convenience wrapper around unsubscribe_optional_max_msgs

pub async fn unsubscribe_optional_max_msgs<'_>(
    &'_ self,
    sid: Sid,
    max_msgs: Option<u64>
) -> Result<()>

UNSUBscribe from a subscription ID

Arguments

• sid - The subscription id to unsubscribe from
• max_msgs - Unsubscribe after receiving the specified number of messages. If this is None, the subscription is immediately unsubscribed.

pub async fn unsubscribe_all<'_>(&'_ self) -> Result<()>

Unsubscribe from all subscriptions

pub async fn info_stream<'_>(&'_ self) -> WatchReceiver<Info>

Get a watch stream of INFO messages received from the server

pub async fn ping_stream<'_>(&'_ self) -> WatchReceiver<()>

Get a watch stream of PING messages received from the server

pub async fn pong_stream<'_>(&'_ self) -> WatchReceiver<()>

Get a watch stream of PONG messages received from the server

pub async fn ok_stream<'_>(&'_ self) -> WatchReceiver<()>

Get a watch stream of +OK messages received from the server

pub async fn err_stream<'_>(&'_ self) -> WatchReceiver<ProtocolError>

Get a watch stream of -ERR messages received from the server

pub async fn ping<'_>(&'_ self) -> Result<()>

Send a PING to the server.

This method, coupled with a pong_stream, can be a useful way to check that the client is still connected to the server.

pub async fn pong<'_>(&'_ self) -> Result<()>

Send a PONG to the server.

Note: you do not have to manually send a PONG as part of the servers ping/pong keep alive. The client library automatically handles replying to pings. You should not need to use this method.

pub async fn ping_pong<'_>(&'_ self) -> Result<()>

Send a PONG and wait for a PONG from the server

Trait Implementations

impl Drop for Client

fn drop(&mut self)

Executes the destructor for this type.

impl Clone for Client

fn clone(&self) -> Client

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.