feat: added openapi generation for agent

apps/agent/src/openapi.rs

@@ -0,0 +1,45 @@
+use tracing::info;
+use utoipa::OpenApi;
+
+pub mod tag {
+    /// nginx
+    pub const NGINX_TAG: &str = "Nginx Agent";
+}
+
+#[derive(utoipa::OpenApi)]
+#[openapi(
+  paths(
+    crate::routes::status,
+    crate::routes::validate,
+    crate::routes::validate_and_reload,
+    crate::routes::write_config,
+  ),
+  components(
+      schemas(crate::routes::StatusResp),
+      schemas(crate::routes::ValidateAndReloadResp),
+      schemas(crate::routes::ValidateBody),
+      schemas(crate::routes::WriteConfigBody),
+      schemas(crate::routes::ValidateAndReloadBody),
+  ),
+  tags(
+      (name = tag::NGINX_TAG, description = "Nginx Agent API"),
+  )
+)]
+struct ApiDoc;
+
+pub struct GenerateOpenapiArgs {
+    pub output: String,
+}
+
+pub async fn generate_openapi_doc(
+    args: &GenerateOpenapiArgs,
+) -> Result<(), Box<dyn std::error::Error + Send + Sync>> {
+    info!("Generating OpenAPI documentation...");
+    let doc = ApiDoc::openapi();
+    let json = doc
+        .to_pretty_json()
+        .expect("Failed to serialize OpenAPI doc to JSON");
+    std::fs::write(&args.output, json).expect("Failed to write OpenAPI doc to file");
+    info!("OpenAPI documentation generated at {}", args.output);
+    Ok(())
+}