How change port using rocket (rust)?

Question

How can i change the port running rocket? The default port is 8000 but it's already busy in my laptop, i wish to change. My Cargo.toml :

[package]
name = "hello_world"
version = "0.1.0"
edition = "2021"

# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

[dependencies]
rocket = "0.5.0-rc.3"

And my main.rs is:

#[macro_use]
extern crate rocket;

#[get("/<name>/<age>")]
fn hello(name: &str, age: u8) -> String {
    format!("Hello, {} year old named {}!", age, name)
}

#[launch]
fn rocket() -> _ {
    rocket::build().mount("/hello", routes![hello])
}

And i'm getting this error:

Error: Rocket failed to bind network socket to given address/port.

Answer 1

People here made me read the doc, and it was easy to solve it just by creating a Rocket.toml, specifying the port on code or set directly, like this:

The following code I made by myself is a little different from the code in the doc, but it works perfectly:

#[macro_use]
extern crate rocket;

#[get("/")]
fn hello() -> &'static str {
    "Hello, World!"
}

#[launch]
fn rocket() -> _ {
    rocket::build()
        .configure(rocket::Config::figment().merge(("port", 9797)))
        .mount("/", routes![hello])
}

You can set the ROCKET_PORT Env directly like this:

ROCKET_PORT=3721 ./your_application

Or you can create a Rocket.toml like this:

[development]
address = "localhost"
port = 9090
workers = 4
keep_alive = 5
read_timeout = 5
write_timeout = 5
log = "normal"
secret_key = "randomly generated at launch"
limits = { forms = 32768 }

[staging]
address = "localhost"
port = 9090
workers = 4
keep_alive = 5
read_timeout = 5
write_timeout = 5
log = "normal"
secret_key = "randomly generated at launch"
limits = { forms = 32768 }

[production]
address = "localhost"
port = 9090
workers = 4
keep_alive = 5
read_timeout = 5
write_timeout = 5
log = "critical"
secret_key = "randomly generated at launch"
limits = { forms = 32768 }

and then you can use the environment dep and then parse the Rocket.toml info in the rocket func.