Struct kvarn::shutdown::Manager

pub struct Manager { /* private fields */ }

Shutdown manager. Contains a counter of connections and a shutdown flag to determine when to initiate a shutdown.

This will wait for all current connections to close, but immediately closes listeners.

Waiting on shutdown is handled using [tokio::sync::watch].

Implementations

impl Manager

pub fn new(_capacity: usize) -> Self

Creates a new shutdown manager with the capacity of the list of wakers set to _capacity.

pub fn get_initate_shutdown_watcher(&self) -> WatchReceiver<()>

Available on crate feature graceful-shutdown only.

Gets a watcher for when the shutdown is initiated

pub fn add_connection(&self)

Adds to the count of connections. When this connection is closed, you must call Manager::remove_connection or a logic error will occur and a shutdown will never happen.

pub fn remove_connection(&self)

Removes from the count of connections. If the count reaches 0 and the internal shutdown flag is enabled, it will initiate a graceful shutdown.

pub fn get_connecions(&self) -> isize

Retrieves the number of current connections. Returns 0 if the feature graceful-shutdown is disabled.

pub fn get_shutdown(&self, order: Ordering) -> bool

Available on crate feature graceful-shutdown only.

Gets the value of the internal shutdown flag. This signals a graceful shutdown is underway.

pub fn build(self) -> Arc<Self>

Wraps Self in a Arc to use across [tokio::task]s.

pub fn shutdown(&self)

Available on crate feature graceful-shutdown only.

Makes Kvarn perform a graceful shutdown.

This requires you to be on a thread with a Tokio runtime. If you create new std threads, you can use Handle::current() to get a movable handle of your runtime. Then call Handle::enter at the start of your thread’s execution and bind it to a shadow variable (e.g. let _runtime = runtime_handle.enter()). That keeps the reference alive during the thread’s whole lifespan.

pub async fn wait(&self)

Waits for Kvarn to enter the shutdown state.

This is ran after the Self::wait_for_pre_shutdown hook, which enables you to do work before this is resolved.

If the feature graceful-shutdown is disabled, this blocks forever.

pub fn wait_for_pre_shutdown( &self ) -> impl Future<Output = UnboundedSender<()>> + '_

Hooks into the stage before Kvarn signals it’s shutdown. Use with care. See comment below.

You MUST send () to the returned sender ONCE when you are done shutting down. Abuse of this guarantee leads to unwanted timing of shutdown, or none.

You can call Self::shutdown before awaiting the returned future.

If the feature graceful-shutdown is disabled, this blocks forever.

Trait Implementations

impl Debug for Manager

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

Formats the value using the given formatter.