Creating a health check endpoint

We're going to get rid of the previous endpoints and create a health check endpoint. This endpoint will be used to check if the application is running and ready to receive requests.

This endpoint will be very basic and will just return a 200 OK response with custom header containing the version (this is just for fun, not really needed at all).

Armed with the knowledge we've gained so far, we should be able to handle this change.

Exercise: Create a health check endpoint

  • The route should be /health and use the GET method.
  • The response should be a 200 OK with a custom header named versioncontaining the version (a &str containing "v0.0.1" for example).
  • As a hint, you can check the code in Actix Web docs to see how to return a simple 200 OK response.
  • You can also check out the HttpResponse docs to see how to add a header to the response.

Can you do it?

Solution
  • Remove the previous endpoints.
  • Create a new endpoint with the route /health and the method GET.
#![allow(unused)]
fn main() {
use actix_web::{get, HttpResponse};

#[get("/health")]
async fn health() -> HttpResponse {
    HttpResponse::Ok()
        .append_header(("version", "0.0.1"))
        .finish()
}
}
  • Configure the services in your shuttle crate. Remove the previous services and add the new one.

Your api > shuttle > src > main.rs file should look like this:

#![allow(unused)]
fn main() {
use actix_web::web::ServiceConfig;
use api_lib::health::health;
use shuttle_actix_web::ShuttleActixWeb;
use shuttle_runtime::CustomError;
use sqlx::Executor;

#[shuttle_runtime::main]
async fn actix_web(
    #[shuttle_shared_db::Postgres()] pool: sqlx::PgPool,
) -> ShuttleActixWeb<impl FnOnce(&mut ServiceConfig) + Send + Clone + 'static> {
    // initialize the database if not already initialized
    pool.execute(include_str!("../../db/schema.sql"))
        .await
        .map_err(CustomError::new)?;

    let pool = actix_web::web::Data::new(pool);

    let config = move |cfg: &mut ServiceConfig| {
        cfg.app_data(pool).service(health);
    };

    Ok(config.into())
}
}

Test that everything is working by running the following command:

curl -i http://localhost:8000/health

You should get something like this:

HTTP/1.1 200 OK
content-length: 0
version: v0.0.1
date: Sun, 02 Jul 2023 10:35:15 GMT

Commit your changes.

git add .
git commit -m "add health check endpoint"