Enum BufferCfg 

pub enum BufferCfg {
    SpmcRing {
        capacity: usize,
    },
    SingleLatest,
    Mailbox,
}

Buffer configuration for a record type

Selects buffering strategy: SPMC Ring (backlog), SingleLatest (state sync), or Mailbox (commands).

Quick Selection Guide

• High-frequency data (>10 Hz): SpmcRing with tuned capacity
• State/config updates: SingleLatest (only latest matters)
• Commands/one-shot events: Mailbox

Examples

use aimdb_core::buffer::BufferCfg;

let telemetry = BufferCfg::SpmcRing { capacity: 2048 };  // High-freq data
let config = BufferCfg::SingleLatest;                     // State sync
let commands = BufferCfg::Mailbox;                        // Commands

Variants

SpmcRing

SPMC (Single Producer, Multiple Consumer) ring buffer

Best for high-frequency data streams with bounded memory. Fast producers can outrun slow consumers (lag detection). Oldest messages dropped on overflow.

Sizing: capacity = data_rate_hz × lag_seconds (use power-of-2). The Tokio adapter’s broadcast backend rounds capacity up to the next power of two, so the effective capacity can exceed the configured value; metrics report the configured capacity.

Fields

capacity: usize

Maximum number of items in the buffer

SingleLatest

Single latest value buffer (no backlog)

Only most recent value is kept. Consumers always get latest state. Intermediate updates are collapsed. Use when history doesn’t matter.

A reader that subscribes after a value has already been produced observes that value once, as if it had been pushed after subscription — a late subscriber to state wants the current state, not just future changes. If nothing has been produced yet, the reader waits. This fresh-subscriber rule is identical across all runtime adapters (tokio, embassy, and wasm) and is enforced by the shared buffer contract suite.

Mailbox

Single-slot mailbox with overwrite

New value overwrites old if not consumed: delivery is at-most-once per value — an unconsumed value is lost on overwrite. Use for commands where the latest command wins.

With multiple subscribers, consumption is competitive: each value is taken by exactly one subscriber, nondeterministically. Unlike SpmcRing and SingleLatest, a mailbox does not fan out.

Implementations

impl BufferCfg

pub fn validate(&self) -> Result<(), &'static str>

Validates the buffer configuration

Returns Err if SPMC Ring capacity is 0.

pub fn name(&self) -> &'static str

Returns a human-readable name for this buffer type

Trait Implementations

impl Clone for BufferCfg

fn clone(&self) -> BufferCfg

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for BufferCfg

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

Formats the value using the given formatter.

impl Default for BufferCfg

fn default() -> Self

Returns the default buffer configuration: SpmcRing { capacity: 1024 }

impl<'de> Deserialize<'de> for BufferCfg

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

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Display for BufferCfg

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

Formats the value using the given formatter.

impl Eq for BufferCfg

impl PartialEq for BufferCfg

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

Equality operator ==.

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

Inequality operator !=.

impl Serialize for BufferCfg

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 BufferCfg