Building a microservice in rust

This project is a companion to my talk at ConFoo about building a rust project.

You should checkout a fully fleshed out starter template for building microservices at tarkalabs/muservice-rs.

If you just cloned the repo you'd want to get to the step-0 branch.

git checkout step-0

Step 1

This step adds the dependencies like tokio, anyhow and tracing_subscriber. This sets the project up for non-blocking IO and adds logging and error handling libraries.

This also configures the binary to log if RUST_LOG=debug environment variable is set.

RUST_LOG=debug cargo run

Step 2

This steps refactors the application into a library and a binary. This allows multiple binary endpoints that may use the same underlying crate for things like the SQS worker or the HTTP handler.

Step 3

This step adds axum and sets up a hello world endpoint.

• Setup and start server - ./src/server.rs
• Router - ./src/router.rs
• Error - ./src/error.rs

Step 4

This step adds serde and serde_json for serializing structs. We need this for reading the request body and returning JSON.

• Path Parameters - ./src/router/path_handler.rs
• Query Parameters - ./src/router/query_handler.rs
• JSON body handler - ./src/router/json_handler.rs

Step 5

This steps adds database handling to our service. Here we are using postgresql with sqlx. We are also going to add chrono for our date types and async_trait to build a repository trait and an implementation for it using the concrete database. This will help us test the router with just a mock implementation of the trait while the DAO tests can hit the actual database.

We'll need an environment variable called DATABASE_URL for cargo to build and run type checked SQL. You can opt out of it but I prefer it.

I've set my DATABASE_URL to postgres:///testdb

• DAO - ./src/dao/mod.rs
• Tasks - ./src/dao/tasks.rs
• App State - ./src/app/mod.rs
• API - ./src/router/tasks_api.rs

Run git checkout step-06 to get to the next step.

Step 6

In this step we accept an Authorization header. If the authorization header is not present or if it is incorrect we present a 401. If not we show the claims as a JSON object.

• Secure Route - ./src/router/auth_endpoint.rs
• Include Secret - ./src/app/mod.rs and ./src/router.rs

http localhost:3000/api/secure Authorization:eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiI0MiIsIm5hbWUiOiJWYWdtaSIsImlhdCI6MTUxNjIzOTAyMiwiZXhwIjoxODc3MjI0Njk2fQ.ePx-Gzd6-PsZ2vKn7v5QmpgAt8vQ8c5AgXLsHR1AFR0

• Bootstrap Rust project
• Add tokio and anyhow and run as an async binary
• Library and binary structure and setup tracing
• Add axum and setup a hello world endpoint
• Explore different extractors for Path, Body and Query Params
• Add database support with sqlx and postgres
• Authentication based on a JWT token