refactor: split http layer

src/app.rs

@@ -1,156 +0,0 @@
-use crate::{
-    config::AppConfig, error::AppError, pokemon::PokeApiClient, rate_limit::RateLimiter,
-    service::PokedexService, telemetry::Telemetry, translation::TranslationClient,
-};
-use axum::{
-    Json, Router,
-    extract::{MatchedPath, Path, Request, State},
-    http::{StatusCode, header},
-    middleware,
-    response::{IntoResponse, Response},
-    routing::get,
-};
-use serde::Serialize;
-use std::{sync::Arc, time::Instant};
-use tower::ServiceBuilder;
-use tower_http::{
-    ServiceBuilderExt,
-    request_id::MakeRequestUuid,
-    trace::{DefaultOnResponse, TraceLayer},
-};
-
-#[derive(Clone)]
-pub struct AppState {
-    service: Arc<PokedexService>,
-    telemetry: Arc<Telemetry>,
-    rate_limiter: Arc<RateLimiter>,
-}
-
-impl AppState {
-    #[must_use]
-    pub fn new(service: PokedexService, telemetry: Telemetry, rate_limiter: RateLimiter) -> Self {
-        Self {
-            service: Arc::new(service),
-            telemetry: Arc::new(telemetry),
-            rate_limiter: Arc::new(rate_limiter),
-        }
-    }
-
-    pub fn from_config(config: &AppConfig) -> Result<Self, AppError> {
-        let telemetry = Telemetry::new(&config.service_name);
-        let pokemon = PokeApiClient::new(&config.pokeapi_base_url, config.request_timeout)?;
-        let translations =
-            TranslationClient::new(&config.translations_base_url, config.request_timeout)?;
-        let service = PokedexService::new(pokemon, translations, telemetry.metrics());
-        Ok(Self::new(
-            service,
-            telemetry,
-            RateLimiter::new(config.rate_limit_per_second, config.rate_limit_burst)
-                .map_err(|_| AppError::Internal)?,
-        ))
-    }
-}
-
-pub fn create_app(state: AppState) -> Router {
-    let tracing_layers = ServiceBuilder::new()
-        .set_x_request_id(MakeRequestUuid)
-        .layer(
-            TraceLayer::new_for_http()
-                .make_span_with(|request: &Request| {
-                    let request_id = request
-                        .headers()
-                        .get("x-request-id")
-                        .and_then(|value| value.to_str().ok())
-                        .unwrap_or("unknown");
-                    tracing::info_span!(
-                        "http.request",
-                        method = %request.method(),
-                        uri = %request.uri(),
-                        request_id = %request_id,
-                    )
-                })
-                .on_response(DefaultOnResponse::new()),
-        )
-        .propagate_x_request_id();
-
-    Router::new()
-        .route("/health", get(health))
-        .route("/metrics", get(metrics))
-        .route("/pokemon/{name}", get(get_pokemon))
-        .route("/pokemon/translated/{name}", get(get_translated_pokemon))
-        .with_state(state.clone())
-        .layer(middleware::from_fn_with_state(
-            state.clone(),
-            enforce_rate_limit,
-        ))
-        .layer(middleware::from_fn_with_state(state, record_http_metrics))
-        .layer(tracing_layers)
-}
-
-async fn health() -> Json<HealthResponse> {
-    Json(HealthResponse { status: "ok" })
-}
-
-async fn metrics(State(state): State<AppState>) -> Result<impl IntoResponse, AppError> {
-    let body = state.telemetry.render_prometheus()?;
-    Ok(([(header::CONTENT_TYPE, "text/plain; version=0.0.4")], body))
-}
-
-async fn enforce_rate_limit(
-    State(state): State<AppState>,
-    req: Request,
-    next: middleware::Next,
-) -> Response {
-    if state.rate_limiter.try_acquire() {
-        next.run(req).await
-    } else {
-        (
-            StatusCode::TOO_MANY_REQUESTS,
-            Json(serde_json::json!({ "error": "rate limit exceeded" })),
-        )
-            .into_response()
-    }
-}
-
-async fn record_http_metrics(
-    State(state): State<AppState>,
-    req: Request,
-    next: middleware::Next,
-) -> Response {
-    let start = Instant::now();
-    let method = req.method().clone();
-    let path = req.extensions().get::<MatchedPath>().map_or_else(
-        || req.uri().path().to_owned(),
-        |path| path.as_str().to_owned(),
-    );
-
-    let response = next.run(req).await;
-    let status = response.status();
-    state.telemetry.metrics().record_http_request(
-        method.as_str(),
-        &path,
-        status.as_u16(),
-        start.elapsed(),
-    );
-
-    response
-}
-
-async fn get_pokemon(
-    State(state): State<AppState>,
-    Path(name): Path<String>,
-) -> Result<Json<crate::domain::PokemonInfo>, AppError> {
-    state.service.get_basic(&name).await.map(Json)
-}
-
-async fn get_translated_pokemon(
-    State(state): State<AppState>,
-    Path(name): Path<String>,
-) -> Result<Json<crate::domain::PokemonInfo>, AppError> {
-    state.service.get_translated(&name).await.map(Json)
-}
-
-#[derive(Serialize)]
-struct HealthResponse {
-    status: &'static str,
-}

src/bin/pokedex-api.rs

@@ -2,16 +2,16 @@
 #![deny(clippy::all, clippy::pedantic, clippy::nursery, clippy::cargo)]
 #![allow(clippy::missing_errors_doc, clippy::multiple_crate_versions)]
 
-use pokedex_api::{app, config::AppConfig, telemetry};
+use pokedex_api::{config::AppConfig, http, telemetry};
 
 #[tokio::main]
 async fn main() -> Result<(), Box<dyn std::error::Error>> {
     telemetry::init_tracing();
     let config = AppConfig::from_env()?;
     let listener = tokio::net::TcpListener::bind(config.bind_addr).await?;
-    let state = app::AppState::from_config(&config)?;
+    let state = http::AppState::from_config(&config)?;
 
-    axum::serve(listener, app::create_app(state))
+    axum::serve(listener, http::create_app(state))
         .with_graceful_shutdown(shutdown_signal())
         .await?;
 

src/http/handlers.rs

@@ -0,0 +1,37 @@
+use super::AppState;
+use crate::{domain::PokemonInfo, error::AppError};
+use axum::{
+    Json,
+    extract::{Path, State},
+    http::header,
+    response::IntoResponse,
+};
+use serde::Serialize;
+
+pub(super) async fn health() -> Json<HealthResponse> {
+    Json(HealthResponse { status: "ok" })
+}
+
+pub(super) async fn metrics(State(state): State<AppState>) -> Result<impl IntoResponse, AppError> {
+    let body = state.telemetry.render_prometheus()?;
+    Ok(([(header::CONTENT_TYPE, "text/plain; version=0.0.4")], body))
+}
+
+pub(super) async fn get_pokemon(
+    State(state): State<AppState>,
+    Path(name): Path<String>,
+) -> Result<Json<PokemonInfo>, AppError> {
+    state.service.get_basic(&name).await.map(Json)
+}
+
+pub(super) async fn get_translated_pokemon(
+    State(state): State<AppState>,
+    Path(name): Path<String>,
+) -> Result<Json<PokemonInfo>, AppError> {
+    state.service.get_translated(&name).await.map(Json)
+}
+
+#[derive(Serialize)]
+pub(super) struct HealthResponse {
+    status: &'static str,
+}

src/http/middleware.rs

@@ -0,0 +1,49 @@
+use super::AppState;
+use axum::{
+    Json,
+    extract::{MatchedPath, Request, State},
+    http::StatusCode,
+    middleware,
+    response::{IntoResponse, Response},
+};
+use std::time::Instant;
+
+pub(super) async fn enforce_rate_limit(
+    State(state): State<AppState>,
+    req: Request,
+    next: middleware::Next,
+) -> Response {
+    if state.rate_limiter.try_acquire() {
+        next.run(req).await
+    } else {
+        (
+            StatusCode::TOO_MANY_REQUESTS,
+            Json(serde_json::json!({ "error": "rate limit exceeded" })),
+        )
+            .into_response()
+    }
+}
+
+pub(super) async fn record_http_metrics(
+    State(state): State<AppState>,
+    req: Request,
+    next: middleware::Next,
+) -> Response {
+    let start = Instant::now();
+    let method = req.method().clone();
+    let path = req.extensions().get::<MatchedPath>().map_or_else(
+        || req.uri().path().to_owned(),
+        |path| path.as_str().to_owned(),
+    );
+
+    let response = next.run(req).await;
+    let status = response.status();
+    state.telemetry.metrics().record_http_request(
+        method.as_str(),
+        &path,
+        status.as_u16(),
+        start.elapsed(),
+    );
+
+    response
+}

src/http/mod.rs

@@ -0,0 +1,89 @@
+mod handlers;
+mod middleware;
+
+use crate::{
+    config::AppConfig, error::AppError, pokemon::PokeApiClient, rate_limit::RateLimiter,
+    service::PokedexService, telemetry::Telemetry, translation::TranslationClient,
+};
+use axum::{Router, extract::Request, middleware as axum_middleware, routing::get};
+use std::sync::Arc;
+use tower::ServiceBuilder;
+use tower_http::{
+    ServiceBuilderExt,
+    request_id::MakeRequestUuid,
+    trace::{DefaultOnResponse, TraceLayer},
+};
+
+#[derive(Clone)]
+pub struct AppState {
+    pub(super) service: Arc<PokedexService>,
+    pub(super) telemetry: Arc<Telemetry>,
+    pub(super) rate_limiter: Arc<RateLimiter>,
+}
+
+impl AppState {
+    #[must_use]
+    pub fn new(service: PokedexService, telemetry: Telemetry, rate_limiter: RateLimiter) -> Self {
+        Self {
+            service: Arc::new(service),
+            telemetry: Arc::new(telemetry),
+            rate_limiter: Arc::new(rate_limiter),
+        }
+    }
+
+    pub fn from_config(config: &AppConfig) -> Result<Self, AppError> {
+        let telemetry = Telemetry::new(&config.service_name);
+        let pokemon = PokeApiClient::new(&config.pokeapi_base_url, config.request_timeout)?;
+        let translations =
+            TranslationClient::new(&config.translations_base_url, config.request_timeout)?;
+        let service = PokedexService::new(pokemon, translations, telemetry.metrics());
+        Ok(Self::new(
+            service,
+            telemetry,
+            RateLimiter::new(config.rate_limit_per_second, config.rate_limit_burst)
+                .map_err(|_| AppError::Internal)?,
+        ))
+    }
+}
+
+pub fn create_app(state: AppState) -> Router {
+    let tracing_layers = ServiceBuilder::new()
+        .set_x_request_id(MakeRequestUuid)
+        .layer(
+            TraceLayer::new_for_http()
+                .make_span_with(|request: &Request| {
+                    let request_id = request
+                        .headers()
+                        .get("x-request-id")
+                        .and_then(|value| value.to_str().ok())
+                        .unwrap_or("unknown");
+                    tracing::info_span!(
+                        "http.request",
+                        method = %request.method(),
+                        uri = %request.uri(),
+                        request_id = %request_id,
+                    )
+                })
+                .on_response(DefaultOnResponse::new()),
+        )
+        .propagate_x_request_id();
+
+    Router::new()
+        .route("/health", get(handlers::health))
+        .route("/metrics", get(handlers::metrics))
+        .route("/pokemon/{name}", get(handlers::get_pokemon))
+        .route(
+            "/pokemon/translated/{name}",
+            get(handlers::get_translated_pokemon),
+        )
+        .with_state(state.clone())
+        .layer(axum_middleware::from_fn_with_state(
+            state.clone(),
+            middleware::enforce_rate_limit,
+        ))
+        .layer(axum_middleware::from_fn_with_state(
+            state,
+            middleware::record_http_metrics,
+        ))
+        .layer(tracing_layers)
+}

src/lib.rs

@@ -2,10 +2,10 @@
 #![deny(clippy::all, clippy::pedantic, clippy::nursery, clippy::cargo)]
 #![allow(clippy::missing_errors_doc, clippy::multiple_crate_versions)]
 
-pub mod app;
 pub mod config;
 pub mod domain;
 pub mod error;
+pub mod http;
 pub mod pokemon;
 pub mod rate_limit;
 pub mod service;