distributed 3.3.4

CQRS/ES framework for Rust using Plain Old Rust Structs — append-only events, replay, snapshots, outbox, service bus, and pluggable infrastructure
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32

use std::future::Future;

use super::LockError;

/// A single lock instance whose operations yield to the executor instead of
/// blocking the OS thread.
///
/// Every operation is asynchronous because a lock may be backed by I/O: the
/// in-memory lock resolves immediately, but a durable lock (e.g. the SQLx
/// lease-table [`PostgresLock`](super::PostgresLock) /
/// [`SqliteLock`](super::SqliteLock)) acquires and releases by talking to the
/// database. `lock` awaits until the lock becomes free; `try_lock` attempts a
/// single non-blocking acquire; `unlock` releases the lock and (for in-memory)
/// wakes any waiters so they can re-contend.
///
/// All returned futures are `Send` so an async `QueuedRepository` built on this
/// lock keeps its repository futures `Send` (required by the async repo traits).
pub trait Lock: Send + Sync {
    /// Acquire the lock, awaiting until it becomes available.
    fn lock(&self) -> impl Future<Output = Result<(), LockError>> + Send + '_;

    /// Try to acquire the lock without waiting.
    ///
    /// Returns `Ok(true)` if acquired, `Ok(false)` if already held.
    fn try_lock(&self) -> impl Future<Output = Result<bool, LockError>> + Send + '_;

    /// Release the lock, waking any waiters so they can re-contend.
    ///
    /// Idempotent: releasing a lock this caller no longer holds (e.g. an
    /// expired distributed lease that was stolen) is a no-op success.
    fn unlock(&self) -> impl Future<Output = Result<(), LockError>> + Send + '_;
}