Struct nats::ConnectionOptions

pub struct ConnectionOptions<TypeState> { /* fields omitted */ }

A configuration object for a NATS connection.

Implementations

impl ConnectionOptions<NoAuth>

pub fn new() -> ConnectionOptions<NoAuth>

ConnectionOptions for establishing a new NATS Connection.

Example

let options = nats::ConnectionOptions::new();
let nc = options.connect("demo.nats.io")?;

pub fn with_token(self, token: &str) -> ConnectionOptions<Authenticated>

Authenticate with NATS using a token.

Example

let nc = nats::ConnectionOptions::new()
    .with_token("t0k3n!")
    .connect("demo.nats.io")?;

pub fn with_user_pass(
    self,
    user: &str,
    password: &str
) -> ConnectionOptions<Authenticated>

Authenticate with NATS using a username and password.

Example

let nc = nats::ConnectionOptions::new()
    .with_user_pass("derek", "s3cr3t!")
    .connect("demo.nats.io")?;

pub fn with_credentials(
    self,
    path: impl AsRef<Path>
) -> ConnectionOptions<Authenticated>

Authenticate with NATS using a credentials file

Example

let nc = nats::ConnectionOptions::new()
    .with_credentials("path/to/my.creds")
    .connect("connect.ngs.global")?;

impl<TypeState> ConnectionOptions<TypeState>

pub fn with_name(self, name: &str) -> ConnectionOptions<TypeState>

Add a name option to this configuration.

Example

let nc = nats::ConnectionOptions::new()
    .with_name("My App")
    .connect("demo.nats.io")?;

pub const fn no_echo(self) -> ConnectionOptions<TypeState>

Select option to not deliver messages that we have published.

Example

let nc = nats::ConnectionOptions::new()
    .no_echo()
    .connect("demo.nats.io")?;

pub const fn max_reconnects(
    self,
    max_reconnects: Option<usize>
) -> ConnectionOptions<TypeState>

Set the maximum number of reconnect attempts. If no servers remain that are under this threshold, all servers will still be attempted.

Example

let nc = nats::ConnectionOptions::new()
    .max_reconnects(Some(3))
    .connect("demo.nats.io")?;

pub const fn reconnect_buffer_size(
    self,
    reconnect_buffer_size: usize
) -> ConnectionOptions<TypeState>

Set the maximum amount of bytes to buffer when accepting outgoing traffic in disconnected mode.

The default value is 8mb.

Example

let nc = nats::ConnectionOptions::new()
    .reconnect_buffer_size(64 * 1024)
    .connect("demo.nats.io")?;

pub fn connect(self, nats_url: &str) -> Result<Connection>

Establish a Connection with a NATS server.

Multiple servers may be specified by separating them with commas.

Example

let options = nats::ConnectionOptions::new();
let nc = options.connect("demo.nats.io")?;

In the below case, the second server is configured to use TLS but the first one is not. Using the tls_required method can ensure that all servers are connected to with TLS, if that is your intention.

let options = nats::ConnectionOptions::new();
let nc = options.connect("nats://demo.nats.io:4222,tls://demo.nats.io:4443")?;

pub fn set_disconnect_callback<F>(self, cb: F) -> Self where
    F: Fn() + Send + Sync + 'static, 

Set a callback to be executed when connectivity to a server has been lost.

pub fn set_reconnect_callback<F>(self, cb: F) -> Self where
    F: Fn() + Send + Sync + 'static, 

Set a callback to be executed when connectivity to a server has been established.

pub fn set_close_callback<F>(self, cb: F) -> Self where
    F: Fn() + Send + Sync + 'static, 

Set a callback to be executed when the client has been closed due to exhausting reconnect retries to known servers or by completing a drain request.

pub fn set_reconnect_delay_callback<F>(self, cb: F) -> Self where
    F: Fn(usize) -> Duration + Send + Sync + 'static, 

Set a callback to be executed for calculating the backoff duration to wait before a server reconnection attempt.

The function takes the number of reconnects as an argument and returns the Duration that should be waited before making the next connection attempt.

It is recommended that some random jitter is added to your returned Duration.

pub const fn tls_required(self, tls_required: bool) -> Self

Setting this requires that TLS be set for all server connections.

If you only want to use TLS for some server connections, you may declare them separately in the connect string by prefixing them with tls://host:port instead of nats://host:port.

If you want to use a particular TLS configuration, see the nats::tls::tls_connector method and the nats::ConnectionOptions::tls_connector method below to apply the desired configuration to all server connections.

Examples

let nc = nats::ConnectionOptions::new()
    .tls_required(true)
    .connect("tls://demo.nats.io:4443")?;

pub fn tls_connector(self, connector: TlsConnector) -> Self

Allows a particular TLS configuration to be set for upgrading TCP connections to TLS connections.

Note that this also enforces that TLS will be enabled for all connections to all servers.

Examples

let tls_connector = nats::tls::builder()
    .identity(nats::tls::Identity::from_pkcs12(b"der_bytes", "my_password")?)
    .add_root_certificate(nats::tls::Certificate::from_pem(b"my_pem_bytes")?)
    .build()?;

let nc = nats::ConnectionOptions::new()
    .tls_connector(tls_connector)
    .connect("tls://demo.nats.io:4443")?;

Trait Implementations

impl<T> Debug for ConnectionOptions<T>

fn fmt(&self, f: &mut Formatter) -> Result<(), Error>

Formats the value using the given formatter.

impl Default for ConnectionOptions<NoAuth>

fn default() -> ConnectionOptions<NoAuth>

Returns the "default value" for a type.