Trait EffectHandler 

pub trait EffectHandler:
    Send
    + Sync
    + 'static {
    type Input: Serialize + DeserializeOwned + Send + Sync + 'static;
    type Output: Serialize + DeserializeOwned + Send + 'static;
    type Error: Into<EffectFailure> + Send + 'static;

    const NAME: &'static str;

    // Required method
    fn execute(
        &self,
        ctx: &EffectContext,
        input: &Self::Input,
    ) -> impl Future<Output = Result<Self::Output, Self::Error>> + Send;

    // Provided methods
    fn kind(&self) -> EffectKind { ... }
    fn remote_idempotency(&self) -> bool { ... }
    fn retry_policy(&self) -> Option<RetryPolicy> { ... }
    fn attempt_timeout(&self) -> Option<Duration> { ... }
    fn risk(&self) -> RiskLevel { ... }
    fn requires_approval(&self) -> bool { ... }
    fn precondition(
        &self,
        ctx: &EffectContext,
        input: &Self::Input,
    ) -> impl Future<Output = Precondition> + Send { ... }
}

An effect the runtime can execute, and re-execute after a crash, from its stored input.

Implement execute; override the other methods to describe the effect. The defaults are the most cautious choices.

Required Associated Constants

const NAME: &'static str

The effect’s name, e.g. payment.charge. One handler per name.

Required Associated Types

type Input: Serialize + DeserializeOwned + Send + Sync + 'static

What the effect acts on. Stored with the record so recovery can rebuild the call: keep credentials in the handler, not here.

type Output: Serialize + DeserializeOwned + Send + 'static

What the effect produces. Stored and replayed to later callers.

type Error: Into<EffectFailure> + Send + 'static

The handler’s error, classified for the runtime.

Required Methods

fn execute( &self, ctx: &EffectContext, input: &Self::Input, ) -> impl Future<Output = Result<Self::Output, Self::Error>> + Send

Performs the effect once.

Provided Methods

fn kind(&self) -> EffectKind

What re-executing does to the outside world. Defaults to EffectKind::IrreversibleWrite.

fn remote_idempotency(&self) -> bool

Whether the remote system deduplicates on EffectContext::idempotency_key, which execute must send.

fn retry_policy(&self) -> Option<RetryPolicy>

The retry policy; None uses the runtime’s.

fn attempt_timeout(&self) -> Option<Duration>

How long to wait for one attempt; None waits indefinitely.

fn risk(&self) -> RiskLevel

How much damage the effect could do; see RiskPolicy. Defaults to RiskLevel::Low.

fn requires_approval(&self) -> bool

Whether a human must approve the effect before its first attempt; see approval.

fn precondition( &self, ctx: &EffectContext, input: &Self::Input, ) -> impl Future<Output = Precondition> + Send

Checked before the first attempt; see EffectBuilder::precondition.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors