Rust sample api

Example api project using Rust, with warp and sqlx.

File architecture

/domain
    Implementation of the business rules

/db
    Sqlx database adapter

    /migrations
        sql schema to run with sqlx-cli

/api
    Api entry points calling the domain

/commands
    Command line utilities calling the domain

/main
    /adapters
        Adapters wrapping external libraries to implement traits provided by the domain

    /main.rs
        Entry point of the application

    /service_registry.rs
        Factories to create the concrete types of many dependencies

    /util.rs
        Some utility functions

/features
    Scenarios to run with karate

/atomic_counter
    A simple thread safe counter

/println_logger
    A simple logger based on println!

/simple_counter
    A counter which is not thread safe.
    Used to illustrate how to use an adapter with an Arc and a Mutex

/uppercaser
    A simple stateless library

Goals

Dependency injection

• Create services and wire them together
• Use injection through generic
• Use injection through dyn Trait
• Each services can be injected in many consumers
• Each services can hold a mutable state
• Service consumers must expose a trait
• Services should not explicitely implement their consumers traits
• Adapters wrap services into a struct implementing the expected trait

Unit testing

• Run unit tests with equality assertions
• Create mocks implementing a trait returning a predefined value
• Generate a coverage report
• Inject mocks with spies to test wether a dependency was called

Project architecture

• Split one project in multiple files
• Split in multiple projects
• Use cargo workspaces

Error handling

• Seperate error between services and consumers
• Try anyhow
• Try thiserror
• Enrich errors with origin
• Enrich errors with a message

Logging

• Add logs

Database (sqlx)

• Setup sqlx
• Setup migrations
• Run at least one data query with sqlx
• Run at least one data update query with sqlx
• Transactions

HTTP Server

• Setup a web framework to return json
• Route to get all posts
• Route to create a post
• Route to publish a post
• Route to unpublish a post
• Investigate open api v3
• Return meaningfull errors for 4** status codes
• Return 500 on internal errors
• Return a request id in a header

Configuration

• Environment variables
• Read a configuration file in many formats
• Read cli args
• Use secrets from a cloud provider or vault

Continuous integration

• Check formating
• Run additional static analysis tools
• Investigate how to get standard unit tests reports
• Investigate how to get standard coverage reports for unit tests
• Investigate how to get standard integration tests reports
• Investigate how to get standard coverage reports for integration tests

HTTP Client

Sockets

File