Struct ListenerConfig 

pub struct ListenerConfig {
    pub addr: SocketAddr,
    pub idle_timeout: Duration,
    pub slow_threshold: Duration,
    pub auth_required: bool,
    pub tls: Option<ServerTls>,
    pub max_connections: usize,
    pub observer: Option<Arc<dyn MetricsObserver>>,
}

Listener configuration. Family posture keeps binds loopback/private by default (SRV-040 guidance).

Fields

addr: SocketAddr

Address to bind. Port 0 picks an ephemeral port — read it back via ListenerHandle::local_addr.

idle_timeout: Duration

Per-read idle timeout (slow-loris resistance, SRV-009). Zero disables, matching each product’s current posture.

slow_threshold: Duration

Commands slower than this bump slow_commands_total (SRV-030). Zero disables the counter.

auth_required: bool

Whether this deployment enforces credentials (SRV-011).

This is policy, not protocol: the profile fixes the handshake shape (does the client lead with HELLO? does it authenticate via AUTH?), while this flag decides whether the server actually refuses un-credentialed sessions. Both family products that authenticate on the RPC path expose exactly this toggle — Nexus’s auth_required and Synap’s require_auth — and an open Synap deployment is the reason it must live here rather than in the profile.

Ignored under Handshake::None, which has no gate at all. Defaults to true: a deployment opens up only by saying so.

tls: Option<ServerTls>

Optional TLS (SRV-040 / SPEC-008 CAN-020). Some turns TLS on for this deployment; None (the default) keeps it plaintext. Requires the crate’s tls feature — a listener configured with TLS but built without it fails to start rather than silently serving plaintext.

max_connections: usize

Maximum concurrently open connections; further accepts are refused. 0 (the default) means unbounded.

This is a different resource from Config::max_in_flight, which bounds in-flight requests per connection: ten thousand idle connections each hold a reader task, a writer task and a BufWriter no matter what max_in_flight says. Operators bound memory and slow-loris exposure with this knob — Synap’s network.max_connections is exactly it.

Refusal, not queueing: at capacity the socket is dropped immediately, so a client fails fast instead of hanging on a connection nobody will ever read. Each refusal increments MetricsSnapshot::connections_refused_total, so a ceiling that is engaging is visible rather than silent.

observer: Option<Arc<dyn MetricsObserver>>

Optional per-command observer (SRV-030 extension).

None (the default) keeps today’s behavior exactly: the built-in counters still record, nothing else runs, and the command label is not even materialized. Install one when an exporter needs per-command dimensions or frame-size distributions that cumulative totals cannot reconstruct — see MetricsObserver.

Implementations

impl ListenerConfig

pub fn new(addr: SocketAddr) -> Self

Config for addr with the defaults: no idle timeout, 1000 ms slow threshold, credentials enforced, plaintext.

pub fn with_observer(self, observer: Arc<dyn MetricsObserver>) -> Self

Install a per-command metrics observer (SRV-030 extension).

pub fn with_max_connections(self, max: usize) -> Self

Refuse accepts beyond max concurrently open connections (SRV-009 analog for connection count). 0 restores the unbounded default.

pub fn with_tls(self, tls: ServerTls) -> Self

Turn TLS on for this deployment (SRV-040): the listener wraps every accepted stream in tokio-rustls before the first Thunder frame.

pub fn open(self) -> Self

Serve un-credentialed sessions — the auth_required = false / require_auth = false posture (e.g. an open Synap deployment).

The handshake shape is unchanged: a client may still send AUTH, and it still succeeds or fails on its own merits; nothing is required.

Trait Implementations

impl Clone for ListenerConfig

fn clone(&self) -> ListenerConfig

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for ListenerConfig

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

Hand-written because observer is a trait object: it reports whether one is installed rather than requiring Debug from every implementer.

impl Default for ListenerConfig

fn default() -> Self

Loopback on an ephemeral port with the standard defaults.