90 lines
2.8 KiB
Markdown
90 lines
2.8 KiB
Markdown
# axum-app-wrapper
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A small plugin layer for `axum` applications, inspired by [fastify](https://fastify.dev/) from the Node/JS ecosystem and the [rocket](https://rocket.rs/) framework.
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Plugins can:
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- add startup state before the final axum state type exists
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- add routes, services, and middleware after state is initialized
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- run graceful shutdown work in reverse registration order
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This crate is intentionally thin. It does not replace axum's router, extractors, or middleware. Rather, it organizes your server setup and teardown into plugins.
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## Lifecycle
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`App::init()` runs plugins in this order:
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1. `on_init` in registration order, passing a `TypeMap` to build state.
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2. `S::try_from(TypeMap)` to build the final typed app state.
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3. `on_setup` in registration order, passing `Router<S>` and `&S`.
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4. `InitializedApp::shutdown()` runs `on_shutdown` consecutively in reverse registration order: the last registered plugin shuts down first, and each hook finishes before the next one starts.
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## Example
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See the `examples` folder for full examples.
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`App::init()` returns an initialized app handle. Use `router()` to get a ready-to-serve `Router<()>`, `state()` to inspect the finalized state, and `shutdown()` from your graceful shutdown path:
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```rust
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let app = App::<AppState>::new()
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.store(config)
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.route("/health", axum::routing::get(health))
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.register(metrics_plugin)
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.init()
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.await?;
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let router = app.router();
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let service_name = &app.state().config.service_name;
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axum::serve(listener, router)
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.with_graceful_shutdown(async move {
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tokio::signal::ctrl_c().await.expect("failed to listen for ctrl-c");
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app.shutdown().await.expect("failed to shut down");
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})
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.await?;
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```
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For `on_setup` closures that access typed state, construct the plugin as
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`AdHocPlugin::<AppState>::new()`. That gives Rust enough context to infer the `state` parameter:
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```rust
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let plugin = AdHocPlugin::<AppState>::new()
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.on_setup(|router, state| {
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let config = Arc::clone(&state.config);
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Ok(router.layer(axum::Extension(config)))
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});
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```
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## Reusable Plugins
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Implement `AppPlugin<S>` directly when setup should be reusable across apps:
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```rust
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use axum::Router;
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use axum_app_wrapper::{AppPlugin, InitFuture, Result, TypeMap};
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use futures::FutureExt;
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struct ConfigPlugin {
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config: Config,
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}
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impl AppPlugin<AppState> for ConfigPlugin {
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fn on_init(&mut self, mut state: TypeMap) -> InitFuture {
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let config = self.config.clone();
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async move {
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state.insert(config);
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Ok(state)
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}
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.boxed()
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}
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fn on_setup(
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&mut self,
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router: Router<AppState>,
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_state: &AppState,
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) -> Result<Router<AppState>> {
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Ok(router.route("/health", axum::routing::get(health)))
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}
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}
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```
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