Struct rocket::error::LaunchError

pub struct LaunchError { /* fields omitted */ }

An error that occurs during launch.

A LaunchError is returned by launch() when launching an application fails.

Panics

A value of this type panics if it is dropped without first being inspected. An inspection occurs when any method is called. For instance, if println!("Error: {}", e) is called, where e: LaunchError, the Display::fmt method being called by println! results in e being marked as inspected; a subsequent drop of the value will not result in a panic. The following snippet illustrates this:

let error = rocket::ignite().launch();

// This line is only reached if launching failed. This "inspects" the error.
println!("Launch failed! Error: {}", error);

// This call to drop (explicit here for demonstration) will do nothing.
drop(error);

When a value of this type panics, the corresponding error message is pretty printed to the console. The following illustrates this:

let error = rocket::ignite().launch();

// This call to drop (explicit here for demonstration) will result in
// `error` being pretty-printed to the console along with a `panic!`.
drop(error);

Usage

A LaunchError value should usually be allowed to drop without inspection. There are two exceptions to this suggestion.

1. If you are writing a library or high-level application on-top of Rocket, you likely want to inspect the value before it drops to avoid a Rocket-specific panic!. This typically means simply printing the value.

2. You want to display your own error messages.

Methods

impl LaunchError

pub fn kind(&self) -> &LaunchErrorKind

Retrieve the kind of the launch error.

Example

let error = rocket::ignite().launch();

// This line is only reached if launch failed.
let error_kind = error.kind();

Trait Implementations

impl Debug for LaunchError

fn fmt(&self, f: &mut Formatter) -> Result

Formats the value using the given formatter.

impl Display for LaunchError

fn fmt(&self, f: &mut Formatter) -> Result

Formats the value using the given formatter.

impl Drop for LaunchError

fn drop(&mut self)

Executes the destructor for this type.

impl Error for LaunchError

fn description(&self) -> &str

Deprecated since 1.42.0:

use the Display impl or to_string()

if let Err(e) = "xc".parse::<u32>() { // Print e itself, no need for description(). eprintln!("Error: {}", e); }

fn source(&self) -> Option<&(dyn Error + 'static)>

The lower-level source of this error, if any.

fn backtrace(&self) -> Option<&Backtrace>

🔬 This is a nightly-only experimental API. (backtrace)

Returns a stack backtrace, if available, of where this error occurred.

fn cause(&self) -> Option<&dyn Error>

Deprecated since 1.33.0:

replaced by Error::source, which can support downcasting

impl From<Error> for LaunchError

fn from(error: Error) -> LaunchError

Performs the conversion.

impl From<Error> for LaunchError

fn from(error: Error) -> LaunchError

Performs the conversion.