Rust API workshop

Write an HTTP API in Rust through a series of test-driven exercises.

The tasks include:

• Call an external HTTP API to retrieve data asynchronously by using reqwest.
• Build an HTTP API by using axum.
• Handle errors by using thiserror and anyhow.
• Write tests by mocking external APIs with wiremock.
• Use tracing for logs and traces. You will visualize traces by running jaeger locally.

What will you build?

A simple HTTP API that checks if Yoda is taller than a given Star Wars character.

For example, if you want to check if Yoda is taller than Luke Skywalker, you can do this GET request with curl:

$ curl 127.0.0.1:3000/taller/luke
{
  "query": "luke",
  "person": "Luke Skywalker",
  "taller": false
}

Architecture

This is the architecture of the system:

graph TD;
    C(HTTP Client)-->S(HTTP Server);
    S-->Swapi;

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• HTTP Client: the software you can use to interact with your API. It can be anything: curl, Insomnia, and so on.
• HTTP Server: the component you will implement.
• Swapi: the service you are going to use to retrieve info about Star Wars characters.

Sequence diagram

This is the flow of the system:

sequenceDiagram
    participant C as HTTP Client
    participant S as HTTP Server
    participant Swapi
    C->>S: Is Yoda taller than Luke?
    S->>Swapi: How tall is Luke?
    Swapi->>S: Luke is *this* tall
    S->>S: Compare Luke vs Yoda height
    S->>C: Yoda is not taller than Luke

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Let's translate some high-level details from the previous diagram:

sequenceDiagram
    participant C as HTTP Client
    participant S as HTTP Server
    participant Swapi
    C->>S: GET /taller/luke
    S->>Swapi: Give me info about Luke
    Swapi->>S: Luke info in JSON
    S->>S: Compare Luke vs Yoda height
    S->>C: {"query":"luke", person":"Luke Skywalker", "taller":false}

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Setup

# Clone this repo
git clone https://github.com/MarcoIeni/rust-api-workshop
cd rust-api-workshop
# Create your branch
git checkout -b workshop
# Run the tests to make sure your rust installation works
cargo test

Get started

Open the rust-api-workshop project in your favorite editor. By looking at the main Cargo.toml, you can see there are two crates:

• workshop: the crate you will use to implement the HTTP API.
• yoda-taller: the crate that contains a possible implementation of the HTTP API. Please, don't look inside this folder before trying to solve the exercises by yourself, first.

To start the workshop, open the file src/workshop/tests/api/main.rs.

Run jaeger

After you finished the workshop, take a look at the final solution (src/yoda-taller), run it and see the traces it produces in jaeger:

# start jaeger (and auto remove on stop)
docker run --name jaeger --rm -d -p6831:6831/udp -p6832:6832/udp -p16686:16686 jaegertracing/all-in-one:latest

# check if it's running
docker ps

# open the web ui
open http://localhost:16686/

cargo run -p yoda-taller

curl http://localhost:3000/taller/luke

Walkthroughs

In the following, you find the recordings of people going through the workshop. If you want to add yours, open a PR!

Credits

Some pieces of code, names or conventions are inspired by:

• zero-to-production
• build-your-own-jira-with-rust