example of rust hello world container (#88)

* example of rust hello world container

* typo

* review

Author: thomas-tacquet

containers/rust-hello-world/Cargo.lock

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+[package]
+name = "hello-world"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]

containers/rust-hello-world/Cargo.toml

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+# Use the official Rust image as the build stage
+FROM rust:1.79.0-alpine3.20 as builder
+
+# Set the working directory inside the container
+WORKDIR /usr/src/app
+
+# Copy the source code to the working directory
+COPY . .
+
+# Build the Rust application
+RUN cargo build --release
+
+# Use a smaller base image for the final container
+FROM alpine:3.20
+
+# Copy the compiled binary from the build stage
+COPY --from=builder /usr/src/app/target/release/hello-world /usr/local/bin/hello-world
+
+# Set the entrypoint command
+CMD ["hello-world"]

containers/rust-hello-world/Dockerfile

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+# Rust hello world
+
+This example demonstrates the deployment of a simple rust http service on Scaleway Serverless Containers.
+
+This can be useful if you come from Serverless Functions and you need to install specific dependencies on your system.
+
+For this example, we will use the CLI to deploy the container, but you can use [other methods](https://www.scaleway.com/en/docs/serverless/containers/reference-content/deploy-container/).
+You can also use the CLI directly from Scaleway console without having to use your credentials.
+
+## Workflow
+
+Here are the different steps we are going to proceed:
+
+- Quick set-up of Container Registry to host our rust container
+- Deploy the Serverless Container
+- Test the container
+
+## Deployment
+
+### Requirements
+
+To complete the actions presented below, you must have:
+- installed and configured the [Scaleway CLI](https://www.scaleway.com/en/docs/developer-tools/scaleway-cli/quickstart/)
+- installed [Docker](https://docs.docker.com/engine/install/) to build the image
+
+### Building the image
+
+1. Run the following command in a terminal to create Container Registry namespace to store the image:
+
+    ```bash
+    scw registry namespace create name=hello-rust
+    ```
+
+  The registry namespace information displays.
+
+1. Copy the namespace endpoint (in this case, `rg.fr-par.scw.cloud/hello-rust`).
+
+1. Log into the Container Registry namespace you created using Docker:
+
+    ```bash
+    docker login rg.fr-par.scw.cloud/hello-rust -u nologin --password-stdin <<< "$SCW_SECRET_KEY"
+    ```
+
+  At this point, you have correctly set up Docker to be able to push your image online.
+
+1. In a terminal, access this directory (containing the Dockerfile), and run the following command to build the image:
+
+    ```bash
+    docker build -t crabnet:v1.0.0 .
+    ```
+
+1. Tag and push the image to the registry namespace:
+
+    ```bash
+    docker tag crabnet:v1.0.0 rg.fr-par.scw.cloud/hello-rust/crabnet:v1.0.0
+    docker push rg.fr-par.scw.cloud/hello-rust/crabnet:v1.0.0
+    ```
+
+### Deploying the image
+
+In a terminal, run the following command to create a Serverless Containers namespace:
+
+    ```bash
+    scw container namespace create name=crabnet
+    ```
+    The namespace information displays.
+
+1. Copy the namespace ID.
+
+1. Run the following command to create and deploy the container:
+
+    ```bash
+    scw container container create namespace-id=<PREVIOUS_NAMESPACE_ID> name=crabnet registry-image=rg.fr-par.scw.cloud/hello-rust/crabnet:v1.0.0
+    ```
+    The container information displays.
+
+1. Copy the DomainName (endpoint) to test your container, you can put the endpoint in your web browser for testing.

containers/rust-hello-world/README.md

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+use std::{
+    io::{prelude::*, BufReader},
+    net::{TcpListener, TcpStream},
+};
+
+fn main() {
+    let listener = TcpListener::bind("127.0.0.1:8080").unwrap();
+
+    for stream in listener.incoming() {
+        let stream = stream.unwrap();
+
+        handle_connection(stream);
+    }
+}
+
+fn handle_connection(mut stream: TcpStream) {
+    let buf_reader = BufReader::new(&mut stream);
+
+    // variable not used but you can manipulate it to get useful informations of the incoming request and manage parameters.
+    let _http_request: Vec<_> = buf_reader
+        .lines()
+        .map(|result| result.unwrap())
+        .take_while(|line| !line.is_empty())
+        .collect();
+
+    let status_line = "HTTP/1.1 200 OK";
+    let contents = "hello world";
+    let length = contents.len();
+
+    let response = format!("{status_line}\r\nContent-Length: {length}\r\n\r\n{contents}");
+
+    stream.write_all(response.as_bytes()).unwrap();
+}