Hyper: Example hello.rs doesn't compile

[malaire]

When trying to compile hello.rs, I get following compiler errors. (Using hyper 0.13.0-alpha.4)

error[E0433]: failed to resolve: use of undeclared type or module `tokio`
  --> src/main.rs:12:3
   |
12 | #[tokio::main]
   |   ^^^^^ use of undeclared type or module `tokio`

error[E0433]: failed to resolve: use of undeclared type or module `pretty_env_logger`
  --> src/main.rs:14:5
   |
14 |     pretty_env_logger::init();
   |     ^^^^^^^^^^^^^^^^^ use of undeclared type or module `pretty_env_logger`

error[E0277]: `main` has invalid return type `impl std::future::Future`
  --> src/main.rs:13:24
   |
13 | pub async fn main() -> Result<(), Box<dyn std::error::Error + Send + Sync>> {
   |                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `main` can only return types that implement `std::process::Termination`
   |
   = help: consider using `()`, or a `Result`

[hwchen]

Are you running it from the hyper repo or did you copy the code into your project? Those warnings look like a Cargo.toml without the right dependencies included.

[malaire]

Copied the example. I havn't seen it mentioned anywhere that example should be run as part of hyper repo, or what dependencies should be included.

[hwchen]

Not sure how familiar you are with Rust and Cargo. To run all the examples in the repo, you can use cargo run --example <example name>. In this case, cargo run --example hello should work.

If you're going to run the code in your own project, you'll have to add these dependencies to your Cargo.toml:

hyper = "0.13.0-alpha.4"
tokio = "0.2.0-alpha.6"
pretty_env_logger = "0.3.1"

Note that hyper is about to upgrade versions, since tokio recently moved to "0.2.0". But for now you have to use the alphas.

[malaire]

I'm still quite new to Rust. I expected examples to be self-contained, but if it is common in Rust to not mention required dependencies for examples, then I guess this issue should be closed.

[hwchen]

Whether or not it's common, I think that for examples like this one it would be helpful to mention the dependencies in the README.

Basically I don't think this needed to be confusing for you, even if you're new to Rust.