pub struct Error { /* private fields */ }Expand description
An error that occurs during launch.
An Error is returned by launch() when launching an
application fails or, more rarely, when the runtime fails after launching.
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: Error, 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:
if let Err(error) = rocket::build().launch().await {
// This println "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::build().launch().await;
// 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
An Error value should usually be allowed to drop without inspection.
There are at least two exceptions:
-
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. -
You want to display your own error messages.
Implementations§
source§impl Error
impl Error
sourcepub fn kind(&self) -> &ErrorKind
pub fn kind(&self) -> &ErrorKind
Retrieve the kind of the launch error.
Example
use rocket::error::ErrorKind;
if let Err(error) = rocket::build().launch().await {
match error.kind() {
ErrorKind::Io(e) => println!("found an i/o launch error: {}", e),
e => println!("something else happened: {}", e)
}
}