---
title: "Step methods"
description: "For the Step concept, read Step."
canonical_url: "https://docs.superdurable.io/zh-Hans/reference/rust/step/"
source: "docs/reference/rust/step.mdx"
locale: "zh-Hans"
---

# Step methods

For the Step concept, read [Step](https://docs.superdurable.io/zh-Hans/concepts/step.md).

<a id="commit-boundary"></a>

## Commits

Dex commits each **WaitFor** call and each **Execute** call separately. Dex
Server holds the Attribute writes and Channel publications of the method. It
commits them together with the returned **Wait** or **StepDecision**, and only
after the method returns successfully. If the method fails, Dex commits none of
them. Calls to external APIs are not part of this commit.

Before it returns, a method can send
[heartbeat checkpoints](https://docs.superdurable.io/zh-Hans/reference/rust/step-options.md#heartbeat) and any number of best-effort
[Stream messages](https://docs.superdurable.io/zh-Hans/concepts/primitives/stream.md). They are not part of the
method's commit. A Stream Store failure does not fail the Step.

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## Step execution local

**set_step_execution_local** stores a value on the current Step execution.
**Execute** reads it with **step_execution_local**. Use it to pass a value from
**WaitFor** to **Execute** when a Flow-level Attribute is more than you need.
Both methods already receive the Step input, so do not copy the input into a
local.

```rust
fn wait_for(&self, context: &mut Context, input: Self::Input) -> HandlerResult<Wait> {
    context.set_step_execution_local("note", format!("approval:{input}"))?;
    Ok(Wait::until(APPROVAL.for_one()))
}

fn execute(&self, context: &mut Context, _input: Self::Input) -> HandlerResult<StepDecision> {
    let note: String = context.step_execution_local("note")?;
    Ok(StepDecision::graceful_complete(note))
}
```

Example: [examples/rust/src/primitives/step_execution_local/flow.rs](https://github.com/superdurable/dex/tree/main/examples/rust/src/primitives/step_execution_local/flow.rs)