Lightweight and secure microservice with a database backend

In this repo, we demonstrate a microservice written in Rust, and connected to a MySQL database. It supports CURD operations on a database table via a HTTP service interface. The microservice is compiled into WebAssembly and runs in the WasmEdge Runtime, which is a secure and lightweight alternative to natively compiled Rust apps in Linux containers. The WasmEdge Runtime can be managed and orchestrated by container tools such as the Docker CLI, Podman, as well as almost all flavors of Kubernetes. It also works with microservice management frameworks such as Dapr.

Everything described in this document is captured in the GitHub Actions CI workflow.

Prerequisites

• Install WasmEdge
• Install Rust
• Install and start MySQL (or TiDB)

You also need to install the wasm32-wasi compiler target to your Rust install.

rustup target add wasm32-wasi

Build

Use the following command to build the microservice. A WebAssembly bytecode file (wasm file) will be created.

cargo build --target wasm32-wasi --release

You can run the AOT compiler on the wasm file. It could significantly improvement the performance of compute-intensive applications. This microservice, however, is a network intensitive application. Our use of async HTTP networking (Tokio and hyper) and async MySQL connectors are crucial for the performance of this microservice.

wasmedgec target/wasm32-wasi/release/order_demo_service.wasm order_demo_service.wasm

Run

You can use the wasmedge command to run the wasm application. It will start the server. Make sure that you pass the MySQL connection string as the env variable to the command.

wasmedge --env "DATABASE_URL=mysql://user:[email protected]:3306/mysql" order_demo_service.wasm

Test

Open another terminal, and you can use the curl command to interact with the web service.

When the microservice receives a GET request to the /init endpoint, it would initialize the database with the orders table.

curl http://localhost:8080/init

When the microservice receives a POST request to the /create_order endpoint, it would extract the JSON data from the POST body and insert an Order record into the database table. For multiple records, use the /create_orders endpoint and POST a JSON array of Order objects.

curl http://localhost:8080/create_orders -X POST -d @orders.json

When the microservice receives a GET request to the /orders endpoint, it would get all rows from the orders table and return the result set in a JSON array in the HTTP response.

curl http://localhost:8080/orders

When the microservice receives a POST request to the /update_order endpoint, it would extract the JSON data from the POST body and update the Order record in the database table that matches the order_id in the input data.

curl http://localhost:8080/update_order -X POST -d @update_order.json

When the microservice receives a GET request to the /delete_order endpoint, it would delete the row in the orders table that matches the id GET parameter.

curl http://localhost:8080/delete_order?id=2

That's it. Feel free to fork this project and use it as a template for your own lightweight microservices!