Macro ctx_async 

macro_rules! ctx_async {
    ($fut:expr, $msg:literal $(,)?) => { ... };
    ($fut:expr, $fmt:literal, $($arg:tt)* $(,)?) => { ... };
}

Attaches context to a future’s error with format string support.

This macro provides a convenient shorthand for attaching context to async operations, similar to how context! works for sync code.

Syntax

• ctx_async!(future, "literal message") - Static message
• ctx_async!(future, "format {}", arg) - Formatted message (formatting is deferred until error)

Examples

use error_rail::prelude_async::*;

#[derive(Debug)]
struct User;

#[derive(Debug)]
struct Profile;

#[derive(Debug)]
struct ApiError;

async fn fetch_user(_id: u64) -> Result<User, ApiError> {
    Err(ApiError)
}

async fn fetch_profile(_id: u64) -> Result<Profile, ApiError> {
    Err(ApiError)
}

async fn example(id: u64) -> BoxedResult<User, ApiError> {
    // Static message
    let user = ctx_async!(fetch_user(id), "fetching user")
        .await
        .map_err(Box::new)?;

    // With formatting (formatting is deferred until error)
    let _profile = ctx_async!(fetch_profile(id), "fetching profile for user {}", id)
        .await
        .map_err(Box::new)?;

    Ok(user)
}