Trait LambdaResultExt

pub trait LambdaResultExt<OK, ERR> {
    // Required methods
    fn handler_error(self) -> Result<OK, HandlerError>;
    fn failure_compat(self) -> Result<OK, Compat<Error>>;
}

Result type extension for AWS that makes it easy to generate a HandlerError object or a Compat<Error> from the failure crate using an existing result. This trait should be imported from the lambda_runtime_core or lambda_runtime crates.

Required Methods

fn handler_error(self) -> Result<OK, HandlerError>

Takes the incoming Result and maps it to a Result that returns an HandlerError object. The HandlerError type already includes implementations of the From trait for most standard library errors. This method is intended to be used when a the From trait is not implemented.

Example

use lambda_runtime_core::{Context, LambdaResultExt, HandlerError, lambda};
use std::error::Error as StdError;

fn main() -> Result<(), Box<dyn StdError>> {
    lambda!(my_handler);
    Ok(())
}

fn my_handler(_event: Vec<u8>, _ctx: Context) -> Result<Vec<u8>, HandlerError> {
    let age = "hello"; // this will throw an error when we try to parse it into an int
    age.parse::<u8>().handler_error()?;

    Ok(vec!())
}

fn failure_compat(self) -> Result<OK, Compat<Error>>

Takes the incoming result and converts it into an Error type from the failure crate wrapped in a Compat object to make it implement the Error trait from the standard library. This method makes it easy to write handler functions that return Compat<Error> directly.

Example

use lambda_runtime_core::{Context, LambdaResultExt, lambda};
use failure::{Error, Compat};
use std::error::Error as StdError;

fn main() -> Result<(), Box<dyn StdError>> {
    lambda!(my_handler);
    Ok(())
}

fn my_handler(_event: Vec<u8>, _ctx: Context) -> Result<Vec<u8>, Compat<Error>> {
    let age = "hello"; // this will throw an error when we try to parse it into an int
    age.parse::<u8>().failure_compat()?;
    Ok(vec!())
}

Implementations on Foreign Types

impl<OK, ERR> LambdaResultExt<OK, ERR> for Result<OK, ERR>

where ERR: Fail + LambdaErrorExt,

fn handler_error(self) -> Result<OK, HandlerError>

fn failure_compat(self) -> Result<OK, Compat<Error>>

Implementors