45 lines
1.9 KiB
Rust
45 lines
1.9 KiB
Rust
use async_trait::async_trait;
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use crate::{errors::DomainError, events::EventId};
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/// How long an `in_progress` claim blocks other deliveries of the same
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/// (event, handler). Past it the claim is presumed dead (crashed worker) and
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/// the next `begin` takes it over. Must exceed any handler's runtime.
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pub const HANDLER_LEASE_SECONDS: i64 = 1800;
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#[derive(Debug, Clone, Copy, PartialEq, Eq)]
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pub enum Begin {
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/// The caller now holds the claim and must run the handler, then
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/// `complete` or `release`.
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Run,
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/// The handler already finished this event; skip it.
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AlreadyDone,
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/// Another delivery holds a live claim; do not run, retry the delivery later.
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InProgressElsewhere,
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}
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/// Per-(event, handler) claim ledger that stops redelivered events from
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/// re-running handlers.
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///
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/// Guarantee: two deliveries never run the same handler for the same event
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/// concurrently (`begin` is atomic across workers). After a crash mid-handler
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/// the claim lapses after `HANDLER_LEASE_SECONDS` and the handler runs again,
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/// so delivery is at-least-once and handlers must be idempotent.
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#[async_trait]
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pub trait ProcessedEventLedger: Send + Sync {
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/// Atomically claims (event, handler): inserts a claim if there is none, or
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/// takes over an `in_progress` claim older than the lease; otherwise
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/// reports the existing state.
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async fn begin(&self, id: &EventId, handler: &str) -> Result<Begin, DomainError>;
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/// Marks the claim done: the handler will not run for this event again.
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async fn complete(&self, id: &EventId, handler: &str) -> Result<(), DomainError>;
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/// Drops an `in_progress` claim so a retry can run immediately.
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async fn release(&self, id: &EventId, handler: &str) -> Result<(), DomainError>;
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/// Removes rows (done, or abandoned `in_progress`) first recorded before
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/// `cutoff`. Returns the number removed.
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async fn delete_older_than(&self, cutoff: chrono::NaiveDateTime) -> Result<u64, DomainError>;
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}
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