Struct IdempotentHandler 

pub struct IdempotentHandler { /* private fields */ }

Wrapper around an EventHandler that adds idempotency tracking.

The IdempotentHandler wraps an inner handler and:

1. Generates a deterministic event ID before calling the inner handler.
2. Tracks which events have been processed (by their deterministic ID).
3. In normal mode, always calls the inner handler (for upsert semantics).
4. Provides the ReplayContext for the inner handler to use.

Note: the inner handler is always called even for already-seen events, because entity upsert is the correct idempotent behavior. The tracking is for observability and metrics, not for skipping events.

Implementations

impl IdempotentHandler

pub fn new(inner: Arc<dyn EventHandler>, replay_ctx: ReplayContext) -> Self

Create a new idempotent handler wrapping the given event handler.

pub fn replay_context(&self) -> &ReplayContext

Returns the current replay context.

pub fn processed_count(&self) -> usize

Returns the number of events processed by this handler.

pub fn has_processed(&self, event_id: &str) -> bool

Returns true if an event with the given deterministic ID has been processed.

pub fn side_effect_guard(&self) -> SideEffectGuard

Create a SideEffectGuard for this handler’s replay context.

Trait Implementations

impl EventHandler for IdempotentHandler

fn handle<'life0, 'life1, 'life2, 'async_trait>( &'life0 self, event: &'life1 DecodedEvent, ctx: &'life2 IndexContext, ) -> Pin<Box<dyn Future<Output = Result<(), IndexerError>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait, 'life2: 'async_trait,

Called for each decoded event that matches the handler’s schema.

fn schema_name(&self) -> &str

The event schema name this handler processes (e.g. "ERC20Transfer").