feat: add agent module with Nginx service commands and routes

- Introduced a new agent module with commands for managing Nginx configurations.
- Implemented `NginxService` for handling reload, validation, and configuration writing.
- Added routes for status, validation, and configuration writing using Axum.
- Created necessary command files: `reload.rs`, `run.rs`, `validate.rs`, `write_config.rs`.
- Updated `Cargo.toml` and `Cargo.lock` to include new dependencies.
- Added `.gitignore` for the agent module.
- Updated `justfile` to include OpenAPI generation for the agent.

apps/agent/src/routes.rs

@@ -0,0 +1,130 @@
+use axum::Json;
+use axum::extract::State;
+use axum::http::StatusCode;
+use axum::response::IntoResponse;
+use serde::{Deserialize, Serialize};
+use serde_json::{Value, from_value};
+use std::sync::Arc;
+use tracing::warn;
+
+use crate::commands::NginxService;
+
+#[derive(Serialize)]
+pub struct StatusResp {
+    pub ok: bool,
+}
+
+pub async fn status() -> impl IntoResponse {
+    let resp = StatusResp { ok: true };
+    (axum::http::StatusCode::OK, axum::Json(resp))
+}
+
+#[derive(Serialize)]
+pub struct ValidateAndReloadResp {
+    pub rc: i32,
+    pub ro: String,
+}
+
+#[derive(Deserialize)]
+pub struct ValidateBody {
+    config_name: String,
+    timestamp: u64,
+}
+
+pub async fn validate(
+    State(nginx_controller): State<Arc<NginxService>>,
+    Json(payload): Json<Value>,
+) -> impl IntoResponse {
+    let params: ValidateBody = match from_value(payload) {
+        Ok(req) => req,
+        Err(e) => {
+            warn!("Invalid validate request: {}", e);
+            return (StatusCode::BAD_REQUEST).into_response();
+        }
+    };
+
+    let (_code, _output) = match nginx_controller
+        .validate(&params.config_name, params.timestamp)
+        .await
+    {
+        Ok(res) => res,
+        Err(e) => {
+            let resp = serde_json::json!({ "error": e.to_string() });
+            return (StatusCode::INTERNAL_SERVER_ERROR, axum::Json(resp)).into_response();
+        }
+    };
+
+    (axum::http::StatusCode::OK,).into_response()
+}
+
+#[derive(Deserialize)]
+pub struct ValidateAndReloadBody {
+    config_name: String,
+    timestamp: u64,
+}
+
+pub async fn validate_and_reload(
+    State(nginx_controller): State<Arc<NginxService>>,
+    Json(payload): Json<Value>,
+) -> impl IntoResponse {
+    let params: ValidateAndReloadBody = match from_value(payload) {
+        Ok(req) => req,
+        Err(e) => {
+            warn!("Invalid validate_and_reload request: {}", e);
+            return (StatusCode::BAD_REQUEST).into_response();
+        }
+    };
+
+    let (code, output) = match nginx_controller
+        .validate_and_reload(&params.config_name, params.timestamp)
+        .await
+    {
+        Ok(res) => res,
+        Err(e) => {
+            let resp = ValidateAndReloadResp {
+                rc: -1,
+                ro: e.to_string(),
+            };
+            return (StatusCode::INTERNAL_SERVER_ERROR, axum::Json(resp)).into_response();
+        }
+    };
+
+    let resp = ValidateAndReloadResp {
+        rc: code,
+        ro: output,
+    };
+    (axum::http::StatusCode::OK, axum::Json(resp)).into_response()
+}
+
+#[derive(Deserialize)]
+pub struct WriteConfigBody {
+    config_name: String,
+    timestamp: u64,
+    content: String,
+}
+
+pub async fn write_config(
+    State(nginx_controller): State<Arc<NginxService>>,
+    Json(payload): Json<Value>,
+) -> impl IntoResponse {
+    let body: WriteConfigBody = match from_value(payload) {
+        Ok(req) => req,
+        Err(e) => {
+            warn!("Invalid write_config request: {}", e);
+            return (StatusCode::BAD_REQUEST).into_response();
+        }
+    };
+
+    match nginx_controller
+        .write_config(&body.config_name, body.timestamp, &body.content)
+        .await
+    {
+        Ok(_) => (),
+        Err(e) => {
+            let resp = serde_json::json!({ "error": e.to_string() });
+            return (StatusCode::INTERNAL_SERVER_ERROR, axum::Json(resp)).into_response();
+        }
+    };
+
+    (axum::http::StatusCode::OK,).into_response()
+}