Struct hydra::Process

pub struct Process { /* private fields */ }

A light weight task that can send and receive messages.

Implementations

impl Process

pub fn alias(reply: bool) -> Reference

Creates a process alias. If reply is true the alias deactivates when the first message is received.

Otherwise, you need to call unalias(reference) to deactivate the alias.

pub fn unalias(alias: Reference) -> bool

Explicitly deactivates a process alias.

Returns true if the alias was currently-active for the current process, or false otherwise.

pub fn current() -> Pid

Returns the current Pid.

Examples found in repository

examples/supervisor.rs (line 75)

    async fn init(&mut self) -> Result<(), ExitReason> {
        let server = Process::current();

        Process::spawn(async move {
            // Ask for a formatted string.
            let hello_world = MyServer::hello(server, "hello")
                .await
                .expect("Failed to call server!");

            tracing::info!("Got: {:?}", hello_world);

            // Wait before crashing.
            Process::sleep(Duration::from_secs(1)).await;

            // Crash the process so the supervisor restarts it.
            MyServer::cast(server, MyMessage::Crash);
        });

        Ok(())
    }

pub fn whereis<S: AsRef<str>>(name: S) -> Option<Pid>

Returns the Pid registered under name or None if the name is not registered.

pub fn send<D: Into<Dests>, M: Receivable>(dests: D, message: M)

Sends a message to dests.

Example:

This method allows sending to multiple targets with certain trade offs:

let pid1 = Process::spawn(async { /* */ });
let pid2 = Process::spawn(async { /* */ });

// faster when all processes are local.
for pid in &[pid1, pid2] {
    Process::send(pid, "hello world!");
}

// faster when processes are mostly remote.
Process::send(&[pid1, pid2], "hello world!");

pub fn send_after<D: Into<Dests>, M: Receivable>( dest: D, message: M, duration: Duration ) -> Reference

Sends a message to dests after the given duration.

See Process::send for performance trade-offs.

Example:

Sends a message after 5 seconds to pid:

Process::send_after(pid, "hello world!", Duration::from_secs(5));

pub fn cancel_timer(timer: Reference)

Cancels a timer created by send_after.

pub fn read_timer(timer: Reference) -> Option<Duration>

Reads a timer created by send_after.

It returns the time remaining until the timer expires.

pub fn receiver() -> ProcessReceiver<()>

Creates a receiver with advanced filtering options from the current processes mailbox.

pub async fn receive<T: Receivable>() -> Message<T>

Creates a receiver for a single message that matches the given type from the current processes mailbox.

This will panic if a message is received that doesn’t match the given type.

pub fn spawn<T>(function: T) -> Pid

where T: Future<Output = ()> + Send + 'static, T::Output: Send + 'static,

Spawns the given function as a process and returns it’s Pid.

Examples found in repository

examples/supervisor.rs (lines 77-90)

    async fn init(&mut self) -> Result<(), ExitReason> {
        let server = Process::current();

        Process::spawn(async move {
            // Ask for a formatted string.
            let hello_world = MyServer::hello(server, "hello")
                .await
                .expect("Failed to call server!");

            tracing::info!("Got: {:?}", hello_world);

            // Wait before crashing.
            Process::sleep(Duration::from_secs(1)).await;

            // Crash the process so the supervisor restarts it.
            MyServer::cast(server, MyMessage::Crash);
        });

        Ok(())
    }

examples/registry.rs (line 73)

    async fn start(&self) -> Result<Pid, ExitReason> {
        // Spawn a registry that will take care of registering 'MySpace'.
        let children = [
            Registry::new("space-registry")
                .with_start(|key| {
                    let RegistryKey::String(id) = key else {
                        panic!()
                    };

                    MySpace::new(id).start_link(GenServerOptions::new())
                })
                .with_shutdown(Shutdown::Infinity)
                .child_spec(RegistryOptions::new())
                .id("space-registry"),
            ChildSpec::new("test-registry")
                .start(move || async { Ok(Process::spawn(test_registry())) }),
        ];

        // Restart only the terminated child.
        Supervisor::with_children(children)
            .strategy(SupervisionStrategy::OneForOne)
            .start_link(SupervisorOptions::new())
            .await
    }

pub fn spawn_link<T>(function: T) -> Pid

where T: Future<Output = ()> + Send + 'static, T::Output: Send + 'static,

Spawns the given function as a process, creates a link between the calling process, and returns the new Pid.

pub fn spawn_monitor<T>(function: T) -> (Pid, Reference)

where T: Future<Output = ()> + Send + 'static, T::Output: Send + 'static,

Spawns the given function as a process, creates a monitor for the calling process, and returns the new Pid.

pub fn alive(pid: Pid) -> bool

Returns true if the given Pid is alive on the local node.

pub async fn sleep(duration: Duration)

Sleeps the current process for the given duration.

Examples found in repository

examples/registry.rs (line 110)

    async fn terminate(&mut self, _reason: ExitReason) {
        tracing::info!("Shutting down MySpace! {:?}", self.id);

        Process::sleep(Duration::from_secs(5)).await;
    }

examples/supervisor.rs (line 86)

    async fn init(&mut self) -> Result<(), ExitReason> {
        let server = Process::current();

        Process::spawn(async move {
            // Ask for a formatted string.
            let hello_world = MyServer::hello(server, "hello")
                .await
                .expect("Failed to call server!");

            tracing::info!("Got: {:?}", hello_world);

            // Wait before crashing.
            Process::sleep(Duration::from_secs(1)).await;

            // Crash the process so the supervisor restarts it.
            MyServer::cast(server, MyMessage::Crash);
        });

        Ok(())
    }

pub async fn timeout<F>( duration: Duration, future: F ) -> Result<<F as Future>::Output, Timeout>

where F: Future,

Waits for the given future to complete until the given duration is up.

pub fn register<S: Into<String>>(pid: Pid, name: S) -> Result<(), ArgumentError>

Registers the given Pid under name if the process is local, active, and the name is not already registered.

pub fn unregister<S: AsRef<str>>(name: S)

Removes the registered name, associated with a Pid.

pub fn registered() -> Vec<String>

Returns a Vec of registered process names.

pub fn list() -> Vec<Pid>

Returns a Vec of Pid’s on the local node.

pub fn link(pid: Pid)

Creates a bi-directional link between the current process and the given process.

pub fn unlink(pid: Pid)

Removes the link between the calling process and the given process.

pub fn monitor<T: Into<Dest>>(process: T) -> Reference

Starts monitoring the given process from the calling process. If the process is already dead a message is sent immediately.

pub fn monitor_alias<T: Into<Dest>>(process: T, reply: bool) -> Reference

Starts monitoring the given process from the calling process. If the process is already dead a message is sent immediately.

Creates an alias for the calling process that’s tied to the process monitor.

The alias will be deactivated if:

• The monitor sends a down message.
• The user explicitly calls unalias. (The monitor will remain active)
• reply is true and a message is sent over the alias.

pub fn demonitor(monitor: Reference)

Demonitors the monitor identified by the given reference.

If a monitor message was sent to the process already but was not received, it will be discarded automatically.

pub fn flags() -> ProcessFlags

Returns the current process flags.

pub fn set_flags(flags: ProcessFlags)

Sets one or more process flags.

Examples found in repository

examples/registry.rs (line 100)

    async fn init(&mut self) -> Result<(), ExitReason> {
        Process::set_flags(ProcessFlags::TRAP_EXIT);

        tracing::info!("Init MySpace for {:?}", self.id);

        Ok(())
    }

pub fn exit<E: Into<ExitReason>>(pid: Pid, exit_reason: E)

Sends an exit signal with the given reason to Pid.

Trait Implementations

impl Drop for Process

fn drop(&mut self)

Executes the destructor for this type.