Struct DnsDiscovery 

pub struct DnsDiscovery {
    pub hostname: String,
    pub port: u16,
    pub refresh_interval_s: u64,
    pub record_type: String,
    pub fail_open: bool,
    pub min_endpoints: u32,
}

DNS-based dynamic upstream discovery (DW-042): when present on an upstream, a background discovery task resolves hostname via DNS, watches the record TTL, and re-resolves when the TTL expires (or at refresh_interval_s, whichever comes first), updating the upstream’s endpoint set live — without a restart. The endpoints field becomes the INITIAL/fallback set: used until the first resolution completes and as a fallback when DNS fails and fail_open is true. When absent, endpoints remain static (the current behavior — no change).

Only A and SRV records are supported. A records pair each resolved address with port; SRV records carry their own port. Consul watch and Kubernetes EndpointSlice watch are deferred to a future milestone — DNS is the first discovery source.

Fields

hostname: String

The DNS hostname to resolve (e.g. my-service.example.com).

port: u16

The port to pair with each resolved A-record address. Ignored for SRV records (they carry their own port).

refresh_interval_s: u64

How often to re-resolve, in seconds (default 30; bounded to 1..=3600). The actual refresh interval is min(refresh_interval_s, record_ttl) so a short-TTL record is refreshed sooner.

record_type: String

DNS record type: "A" (default) or "SRV".

fail_open: bool

If true (default), keep the last resolved endpoint set when DNS fails. If false, clear endpoints on failure (the upstream answers 503 until DNS recovers).

min_endpoints: u32

Minimum endpoints to keep serving (default 1). If a resolution yields fewer than this, the previous set is kept (the upstream does not shrink below the floor).

Trait Implementations

impl Clone for DnsDiscovery

fn clone(&self) -> DnsDiscovery

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for DnsDiscovery

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for DnsDiscovery

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl JsonSchema for DnsDiscovery

fn schema_name() -> Cow<'static, str>

The name of the generated JSON Schema.

fn schema_id() -> Cow<'static, str>

Returns a string that uniquely identifies the schema produced by this type.

fn json_schema(generator: &mut SchemaGenerator) -> Schema

Generates a JSON Schema for this type.

fn inline_schema() -> bool

Whether JSON Schemas generated for this type should be included directly in parent schemas, rather than being re-used where possible using the $ref keyword.

impl PartialEq for DnsDiscovery

fn eq(&self, other: &DnsDiscovery) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Serialize for DnsDiscovery

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl StructuralPartialEq for DnsDiscovery