Crate async_fd_lock

Advisory reader-writer locks for files.

Notes on Advisory Locks

“advisory locks” are locks which programs must opt-in to adhere to. This means that they can be used to coordinate file access, but not prevent access. Use this to coordinate file access between multiple instances of the same program. But do not use this to prevent actors from accessing or modifying files.

Example

use std::path::PathBuf;
use tokio::fs::File;
use tokio::io::{AsyncReadExt, AsyncWriteExt};
use async_fd_lock::{LockRead, LockWrite};

let dir = tempfile::tempdir().unwrap();
let path = dir.path().join("foo.txt");

// Lock it for writing.
{
    let mut write_guard = File::options()
        .create_new(true)
        .write(true)
        .truncate(true)
        .open(&path).await?
        .lock_write().await?;
    write_guard.write(b"bongo cat").await?;
}

// Lock it for reading.
{
    let mut read_guard_1 = File::open(&path).await?.lock_read().await?;
    let mut read_guard_2 = File::open(&path).await?.lock_read().await?;
    let byte_1 = read_guard_1.read_u8().await?;
    let byte_2 = read_guard_2.read_u8().await?;
}

Re-exports

pub use nonblocking::*;

Modules

blocking

nonblocking

Structs

LockError

RwLockReadGuard

A shared lock on a file.

RwLockWriteGuard

An exclusive lock on a file.

Traits

AsOpenFile

A trait to borrow the file descriptor from an underlying object.

Type Aliases

LockReadResult

LockWriteResult