Run a Rust Actix Web app

This example uses actix-web, a popular Rust web framework. To run this example, follow these steps:

1. Install the kraft CLI tool and a container runtime engine, e.g. Docker.

2. Clone the examples repository and cd into the examples/http-rust1.75-actix-web4/ directory:

git clone https://github.com/kraftcloud/examples
cd examples/http-rust1.75-actix-web4/

Make sure to log into KraftCloud by setting your token and a metro close to you. We use fra0 (Frankfurt, 🇩🇪) in this guide:

# Set KraftCloud access token
export KRAFTCLOUD_TOKEN=token
# Set metro to Frankfurt, DE
export KRAFTCLOUD_METRO=fra0

When done, invoke the following command to deploy this application on KraftCloud:

kraft cloud deploy -p 443:8080 .

The output shows the instance URL and other details:

[●] Deployed successfully!
 │
 ├────────── name: http-rust175-actix-web4-3pj27
 ├────────── uuid:33e9b4ba-58d7-4b3a-b9dd-4c406c0e7b07
 ├───────── state: running
 ├─────────── url: https://autumn-silence-wupu2nus.fra0.kraft.host
 ├───────── image: http-rust175-actix-web4@sha256:11723705230f0f4545d2be7e4867dc67b396870769e91f05e2fa6d9da94f9b59
 ├───── boot time: 11.67 ms
 ├──────── memory: 128 MiB
 ├─ service group: autumn-silence-wupu2nus
 ├── private fqdn: http-rust175-actix-web4-3pj27.internal
 ├──── private ip: 172.16.3.3
 └────────── args: /server

In this case, the instance name is http-rust175-actix-web4-3pj27 and the URL is https://autumn-silence-wupu2nus.fra0.kraft.host. They are different for each run.

Use curl to query the KraftCloud instance of the Rust-based HTTP web server:

curl https://autumn-silence-wupu2nus.fra0.kraft.host
curl https://autumn-silence-wupu2nus.fra0.kraft.host/hey

Hello world!
Hey there!

At any point in time, you can list information about the instance:

kraft cloud instance list

NAME                           FQDN                                      STATE    CREATED AT      IMAGE                                                                         MEMORY   ARGS     BOOT TIME
http-rust175-actix-web4-3pj27  autumn-silence-wupu2nus.fra0.kraft.host  running  10 minutes ago  razvan.unikraft.io/http-rust175-actix-web4@sha256:11723705230f0f4545d2be7...  128 MiB  /server  11672us

When done, you can remove the instance:

kraft cloud instance remove http-rust175-actix-web4-3pj27

Customize your Application

To customize the application, update the files in the repository, listed below:

• src/main.rs: the actual implementation
• Cargo.toml: the Cargo package manager configuration file
• Kraftfile: the KraftCloud specification
• Dockerfile: the Docker-specified application filesystem

Kraftfile

spec: v0.6

runtime: base:latest

rootfs: ./Dockerfile

cmd: ["/server"]

src/main.rs

use actix_web::{get, post, web, App, HttpResponse, HttpServer, Responder};

#[get("/")]
async fn hello() -> impl Responder {
    HttpResponse::Ok().body("Hello world!")
}

#[post("/echo")]
async fn echo(req_body: String) -> impl Responder {
    HttpResponse::Ok().body(req_body)
}

async fn manual_hello() -> impl Responder {
    HttpResponse::Ok().body("Hey there!")
}

#[actix_web::main]
async fn main() -> std::io::Result<()> {
    HttpServer::new(|| {
        App::new()
            .service(hello)
            .service(echo)
            .route("/hey", web::get().to(manual_hello))
    })
    .bind(("0.0.0.0", 8080))?
    .run()
    .await
}

Cargo.toml

[package]
name = "hello"
version = "0.0.0"
edition = "2021"
publish = false

[dependencies]
actix-web = "4"

Dockerfile

FROM rust:1.75.0-bookworm AS build

RUN cargo new --bin app
WORKDIR /app
COPY Cargo.toml ./
COPY src ./src
RUN cargo build --release

# This stage is optional but reduces overall image size
FROM scratch
COPY --from=build /app/target/release/hello /server
COPY --from=build /lib/x86_64-linux-gnu/libc.so.6 /lib/x86_64-linux-gnu/
COPY --from=build /lib/x86_64-linux-gnu/libm.so.6 /lib/x86_64-linux-gnu/
COPY --from=build /lib/x86_64-linux-gnu/libgcc_s.so.1 /lib/x86_64-linux-gnu/
COPY --from=build /lib64/ld-linux-x86-64.so.2 /lib64/

The following options are available for customizing the application:

• If only updating the implementation in the src/main.rs source file, no other change is required.

• If new files are added, these have to be copied in the application filesystem, using the COPY command in the Dockerfile. If new Rust source code files are added, be sure to configure required dependencies in the Cargo.toml file.

• If a new executable is built, update the cmd line in the Kraftfile and replace /server with the path to the new executable.

• More extensive changes may require expanding the Dockerfile with additional Dockerfile commands.

Learn More

Use the --help option for detailed information on using KraftCloud:

kraft cloud --help

Or visit the CLI Reference.