Enum DurabilityMode 

pub enum DurabilityMode {
    Local,
    Hybrid,
    DurablyReplicated,
}

Operator-facing durability mode. Each variant maps to one of three named policies that compose the underlying Clause list directly in code, replacing the legacy --durability-policy <STRING> DSL. See docs/replication.md for the three-tier menu in operational terms.

clap::ValueEnum derives --durability-mode <local|hybrid|durably-replicated>.

Variants

Local

persisted>=1. Single-node durability — the primary’s PLP-backed NVMe write is the only confirmation needed. Required when running with --standalone; appropriate for dev/staging deployments without a replica.

Hybrid

persisted>=1 && in_memory>=2. One durable copy on the primary’s disk plus an in-memory ack from a second node. Single-failure-safe with a brief RAM-only window (~80 µs on PLP-backed NVMe) for the secondary copy. The default — typical live trading deployments. Saves ~50–80 µs per fill vs DurablyReplicated. Fails closed when no replica is connected.

DurablyReplicated

persisted>=2. Two durable copies before client ack. Zero RAM-only window; the gate stalls if no replica is currently connected. Compliance-driven venues.

Implementations

impl DurabilityMode

pub fn to_policy(self) -> Policy

Build the underlying Policy for this mode. Every variant’s clause list is hand-constructed from in-range counts, so Policy::new cannot fail — any regression would surface in the unit tests below.

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

CLI / log-friendly name. Matches the clap::ValueEnum kebab-cased spelling.

pub fn parse(s: &str) -> Option<Self>

Parse the admin-channel / CLI wire spelling. Accepts the same kebab-cased strings as_str emits so operators only have to learn one vocabulary across --durability-mode and the admin DURABILITY command.

pub fn as_u8(self) -> u8

Stable u8 discriminant. The response stage publishes the operator-selected mode through an [AtomicU8] so it can detect a runtime swap (via the admin DURABILITY command) with a relaxed load on every gate iteration — cheaper than crossing a Mutex or carrying a refcounted Arc<Policy> snapshot. Values are part of the in-process ABI between admin and response, not a wire format; they must remain stable so the round-trip from_u8(as_u8(x)) == Some(x) always holds.

pub fn from_u8(b: u8) -> Option<Self>

Inverse of [as_u8]. Returns None for an unknown byte — callers initialise the atomic from a valid mode and the admin path only writes as_u8(parse(s)?), so an unknown byte indicates memory corruption or a programmer bug. The response stage logs and retains the prior mode in that case rather than silently falling back.

Trait Implementations

impl Clone for DurabilityMode

fn clone(&self) -> DurabilityMode

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for DurabilityMode

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

Formats the value using the given formatter.

impl Display for DurabilityMode

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

Formats the value using the given formatter.

impl PartialEq for DurabilityMode

fn eq(&self, other: &DurabilityMode) -> 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 ValueEnum for DurabilityMode

fn value_variants<'a>() -> &'a [Self]

All possible argument values, in display order.

fn to_possible_value<'a>(&self) -> Option<PossibleValue>

The canonical argument value.

fn from_str(input: &str, ignore_case: bool) -> Result<Self, String>

Parse an argument into Self.

impl Copy for DurabilityMode

impl Eq for DurabilityMode

impl StructuralPartialEq for DurabilityMode