Struct ConsistencyGate 

pub struct ConsistencyGate {
    pub applied: u64,
    pub required: u64,
}

The server-side gate that enforces a Consistency level the same way on every backend. The client refuses an unadvertised level before sending, but a backend that does advertise read_your_writes or strong_consistency still has to honor the level, and the rule is fail-not-downgrade: serve only when the projector’s applied offset for the queried source has reached the required offset (the source log head at query time), else return QueryError::Stale rather than a silently older read.

This is the offset obligation common to both non-Eventual levels. Strong is read-your-writes plus cross-replica agreement, so a backend serving Strong layers its own cross-replica check on top of a passing gate. Eventual always passes.

Fields

applied: u64

The projector’s applied offset for the queried source.

required: u64

The offset the read must reach before serving (the source log head).

Implementations

impl ConsistencyGate

pub fn new(applied: u64, required: u64) -> Self

A gate for a source whose projector has applied up to applied against a head of required.

pub fn is_caught_up(&self) -> bool

Whether the projector has caught up to the required offset.

pub fn check( &self, level: Consistency, what: impl Into<String>, ) -> Result<(), QueryError>

Enforce level for the source named what. Eventual always passes. A non-Eventual level passes only when is_caught_up, else returns QueryError::Stale carrying the offsets so the caller can retry while the projector catches up.

Trait Implementations

impl Clone for ConsistencyGate

fn clone(&self) -> ConsistencyGate

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for ConsistencyGate

impl Debug for ConsistencyGate

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

Formats the value using the given formatter.

impl Eq for ConsistencyGate

impl PartialEq for ConsistencyGate

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for ConsistencyGate