Design a plugin architecture for the pop-server

francis-pouatcha commented 10 months ago

A plugins architecture will allow the pop-server to b e modularized as of which services are deployed and exposed by the server.

francis-pouatcha commented 9 months ago

Here is my first formulated request to

I need a plugins architecture for a rust api server. Each plugin shall:
- provide a set of features
- provide a web api that can be added to the routes of the server to expose the feature as web API
- provide a handler module for the processing of request sent to that API
- provide config options to add the plugin (as a feature) to the server in the compilation process
- provide a test module to test the plugin

We will be using axum to build the web server.

Implementing a plugin architecture in a Rust API server can be a powerful way to extend the functionality of your server while keeping it modular and maintainable. Here's a high-level outline of how you can approach this using the Axum web framework:

Define the Plugin Trait: Start by defining a trait that represents the interface a plugin must adhere to. This trait should include methods for exposing features, configuring the plugin, and handling requests.
```
pub trait Plugin {
   fn name(&self) -> &str;
   fn configure(&mut self, config: &Config);
   fn routes(&self) -> Vec<axum::Route>;
}
```

Create a Plugin Registry: Create a central registry to manage and load plugins dynamically. This registry should provide methods for registering, configuring, and initializing plugins.

pub struct PluginRegistry {
   plugins: Vec<Box<dyn Plugin>>,
}

impl PluginRegistry {
   pub fn new() -> Self {
       // Initialize an empty registry
       Self { plugins: Vec::new() }
   }

   pub fn register(&mut self, plugin: Box<dyn Plugin>) {
       // Add a plugin to the registry
       self.plugins.push(plugin);
   }

   // Other methods for configuration, initialization, and routing
}

Implement Plugins: Create your individual plugins by implementing the Plugin trait. Each plugin should provide methods for configuring, exposing routes, and handling requests. Here's a simplified example:

struct MyPlugin {
   name: String,
}

impl MyPlugin {
   pub fn new(name: &str) -> Self {
       Self { name: name.to_owned() }
   }
}

impl Plugin for MyPlugin {
   fn name(&self) -> &str {
       &self.name
   }

   fn configure(&mut self, _config: &Config) {
       // Configure the plugin
   }

   fn routes(&self) -> Vec<axum::Route> {
       // Define and return routes for this plugin
       let handler = MyPluginHandler::new();
       vec![get("/myplugin").to(handler.handle)]
   }
}

Initialize and Register Plugins: In your main application, create an instance of the PluginRegistry, initialize your plugins, and register them with the registry.

fn main() {
   let mut registry = PluginRegistry::new();

   // Initialize and register plugins
   let my_plugin = Box::new(MyPlugin::new("MyPlugin"));
   registry.register(my_plugin);

   // Configure and start the Axum server
   // ...
}

Configure Axum Routes: When configuring your Axum server, iterate through the registered plugins and add their routes to your server's router.

let mut app = axum::Router::new();

for plugin in &registry.plugins {
   app = app.nest(&plugin.routes());
}

// Add other routes specific to your application
// ...

// Start the Axum server
axum::Server::bind(&addr)
   .serve(app.into_make_service())
   .await
   .unwrap();

Testing: Create separate test modules for your plugins to test their individual functionality. You can use tools like axum::test to simulate HTTP requests and test your handlers.
Building and Running: When building your server, you can include or exclude plugins based on configuration options or environment variables. This allows you to add or remove features during compilation.

This is a high-level overview of how you can implement a plugin architecture in a Rust API server using Axum. You can expand upon this structure to meet the specific requirements of your project and add more advanced features like dependency injection, error handling, and more.

francis-pouatcha commented 9 months ago

Here are some hints from google bard from the same prompt:

Proposal 1

Here is a possible plugins architecture for a Rust API server using Axum:

The plugins directory contains all of the plugins. Each plugin is a Rust crate that can be compiled and installed separately.
The core directory contains the core functionality of the API server, such as the routing, error handling, and logging.
The server directory contains the code that starts the API server and loads the plugins.

Each plugin must implement the following traits:

Features defines the features that the plugin provides.
WebApi defines the web API that the plugin exposes.
Handler defines the handler module for the processing of requests sent to the API.
Config defines the configuration options for the plugin.
Test defines the test module for the plugin.

The Features trait must define a set of strings that represent the features that the plugin provides. For example, a plugin that provides a user management API might define the following features:

"user_management"

The WebApi trait must define a function that returns a Router instance that defines the routes for the plugin's API. For example, the following code defines a web API for a user management plugin:

pub fn web_api() -> Router {
    Router::new().route("/users", get(handle_get_users))
}

The Handler trait must define a function that handles requests sent to the plugin's API. The function must take a Request and a Response as arguments, and it must return an Result. For example, the following code defines a handler for the /users route in the user management plugin:

pub async fn handle_get_users(req: Request<Body>) -> Result<Response<Body>, Error> {
    let users = get_users();

    Ok(json!(users).into())
}

The Config trait must define a function that returns the configuration options for the plugin. The function must take a Config instance as an argument, and it must return a Result. For example, the following code defines the configuration options for the user management plugin:

pub fn config(config: &Config) -> Result<(), Error> {
    // Validate the configuration options.

    Ok(())
}

The Test trait must define a function that runs the tests for the plugin. The function must take a TestContext instance as an argument, and it must return an Result. For example, the following code defines the tests for the user management plugin:

pub fn test(ctx: &TestContext) -> Result<(), Error> {
    // Create a test user.

    let user = create_user(ctx);

    // Get all users.

    let users = get_users(ctx);

    // Assert that the user was created and is in the list of users.

    assert!(users.contains(&user));

    Ok(())
}

To use a plugin, you must add it to the Cargo.toml file for the API server. For example, the following code adds the user management plugin to the API server:

[dependencies]
axum = {version = "0.5.13", features = ["headers"]}
user_management = {path = "./plugins/user_management"}

You can then start the API server with the following command:

cargo run

The API server will load the user management plugin and make it available to clients.

Proposal 3