Struct MultiResourceLock

pub struct MultiResourceLock { /* private fields */ }

A distributed mutual exclusion lock backed by Redis.

Supports exclusion based on multiple resources and partial overlaps.

This is much less efficient than lock_across. Ideally you should architect your application so you never need MultiResourceLock.

E.g. a lock on resources ["a", "b"] will block a lock on ["a"] or ["b", "c"].

Implementations

impl MultiResourceLock

pub fn new(client: Client) -> RedisResult<Self>

Create a new instance of the lock.

Errors

When Client::get_connection errors.

pub async fn acquire_default( &mut self, resources: &[String], ) -> RedisResult<Option<String>>

Calls MultiResourceLock::acquire with DEFAULT_EXPIRATION, DEFAULT_TIMEOUT and DEFAULT_SLEEP.

Errors

When MultiResourceLock::acquire errors.

pub async fn acquire( &mut self, resources: &[String], expiration: Duration, timeout: Duration, sleep: Duration, ) -> RedisResult<Option<String>>

Attempts to acquire the lock blocking until the lock can be acquired.

Blocks up to timeout duration making attempts every sleep duration.

Returns None when it times out.

Errors

When MultiResourceLock::try_acquire errors.

pub async fn try_acquire_default( &mut self, resources: &[String], ) -> RedisResult<Option<String>>

Calls MultiResourceLock::try_acquire with DEFAULT_EXPIRATION.

Errors

When MultiResourceLock::try_acquire errors.

pub async fn try_acquire( &mut self, resources: &[String], expiration: Duration, ) -> RedisResult<Option<String>>

Attempts to acquire the lock returning immediately if it cannot be immediately acquired.

Errors

• When the acquire_lock function is missing from the Redis instance.

pub async fn release(&mut self, lock_id: &str) -> RedisResult<usize>

Releases a held lock.

Errors

• When the release_lock function is missing from the Redis instance.
• When lock_id does not refer to a held lock.

pub async fn map<F>( &mut self, resources: &[String], expiration: Duration, timeout: Duration, sleep: Duration, f: F, ) -> Result<F::Output, MapError>

where F: Future + Send + 'static, F::Output: Send + 'static,

Since we cannot safely drop a guard in an async context, we need to provide a way to release the lock in case of an error.

This is the suggested approach, it is less ergonomic but it is safe.

pub async fn map_default<F>( &mut self, resources: &[String], f: F, ) -> Result<F::Output, MapError>

where F: Future + Send + 'static, F::Output: Send + 'static,

Calls MultiResourceLock::map with DEFAULT_EXPIRATION, DEFAULT_TIMEOUT and DEFAULT_SLEEP.

Trait Implementations

impl Debug for MultiResourceLock

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

Formats the value using the given formatter.