How to run a Rust web application on Platform.sh

ludoge · March 12, 2019, 1:20pm

Goal

This guide shows how to deploy a simple Rust web app on Platform.sh.

Assumptions

To complete this, you will need:

An empty Platform.sh project
The Platform.sh CLI tool installed
Your ssh key loaded in your ssh agent and configured in the Platform.sh dashboard
The Rust environment installed

Problems

Platform.sh does not provide a dedicated Rust runtime container. It will thus be necessary to install Rust as the project is built.

Steps

1. Create a Rust application

Create a new Rust project:

cargo new platform_howto && cd platform_howto

Set the platform remote:

platform project:set-remote <project id>

Add the following under [dependencies] in Cargo.toml:

warp = "0.1"
clap = "2.32.0"

Replace src/main.rs with:

#[macro_use]
extern crate clap;
use clap::{Arg, App};

use warp::Filter;

fn main() {
    let args = App::new("HOWTO")
        .version("1.0")
        .author("Platform.sh <sayhello@platform.sh>")
        .about("How to run a Rust app on Platform.sh")
        .arg(Arg::with_name("port")
             .short("p")
             .long("port")
             .value_name("PORT")
             .help("Sets a custom port")
             .takes_value(true)
             .required(true))
        .get_matches();


    // Get port from command-line arguments
    let port = value_t!(args, "port", u16).unwrap_or_else(|e| e.exit());

    // Match any request and return hello world!
    let routes = warp::any().map(|| "Hello, World!");

    warp::serve(routes)
        .run(([127, 0, 0, 1], port));
}

2. Configure the application to run on Platform.sh:

Add the following to .platform.app.yaml:

name: app

# Any type will work here
type: "php:7.3"

hooks:
    build: |
      set -e
      curl https://sh.rustup.rs > rustup.sh
      sh rustup.sh -y --default-toolchain stable
      rm rustup.sh
      . "$HOME/.cargo/env"
      cargo build --release

web:
    upstream:
        socket_family: tcp
        protocol: http

    commands:
        start: |
          target/release/platform_howto --port $PORT

disk: 1024

Define a route in .platform/routes.yaml:

"https://{default}/":
    type: upstream
    upstream: "app:http"

Add an empty .platform/services.yaml file:

touch .platform/services.yaml

3. Add, commit and push:

git add .
git commit -m "Rust on Platform.sh"
git push platform master

4. Test by visiting the URL of your project:

platform url

Which should open a browser tab showing Hello, World!

Conclusion

Even without a dedicated runtime, running a Rust application on Platform.sh can be done by leveraging the build hook and the PORT variable.