feat: stabilize Deno.HttpServer.shutdown and Unix socket support (#21463)

This commit stabilizes "Deno.HttpServer.shutdown" API as well as
Unix socket support in "Deno.serve" API.

---------

Co-authored-by: Yoshiya Hinosawa <stibium121@gmail.com>

cli/tsc/dts/lib.deno.ns.d.ts

@@ -5939,6 +5939,50 @@ declare namespace Deno {
     handler: ServeHandler;
   }
 
+  export interface ServeUnixOptions {
+    /** The unix domain socket path to listen on. */
+    path: string;
+
+    /** An {@linkcode AbortSignal} to close the server and all connections. */
+    signal?: AbortSignal;
+
+    /** The handler to invoke when route handlers throw an error. */
+    onError?: (error: unknown) => Response | Promise<Response>;
+
+    /** The callback which is called when the server starts listening. */
+    onListen?: (params: { path: string }) => void;
+  }
+
+  /** Information for a unix domain socket HTTP request.
+   *
+   * @category HTTP Server
+   */
+  export interface ServeUnixHandlerInfo {
+    /** The remote address of the connection. */
+    remoteAddr: Deno.UnixAddr;
+  }
+
+  /** A handler for unix domain socket HTTP requests. Consumes a request and returns a response.
+   *
+   * If a handler throws, the server calling the handler will assume the impact
+   * of the error is isolated to the individual request. It will catch the error
+   * and if necessary will close the underlying connection.
+   *
+   * @category HTTP Server
+   */
+  export type ServeUnixHandler = (
+    request: Request,
+    info: ServeUnixHandlerInfo,
+  ) => Response | Promise<Response>;
+
+  /**
+   * @category HTTP Server
+   */
+  export interface ServeUnixInit {
+    /** The handler to invoke to process each incoming request. */
+    handler: ServeUnixHandler;
+  }
+
   /** An instance of the server created using `Deno.serve()` API.
    *
    * @category HTTP Server
@@ -5959,6 +6003,11 @@ declare namespace Deno {
 
     /** Make the server not block the event loop from finishing. */
     unref(): void;
+
+    /** Gracefully close the server. No more new connections will be accepted,
+     * while pending requests will be allowed to finish.
+     */
+    shutdown(): Promise<void>;
   }
 
   /**
@@ -5978,6 +6027,55 @@ declare namespace Deno {
    * @category HTTP Server
    */
   export function serve(handler: ServeHandler): HttpServer;
+  /** Serves HTTP requests with the given option bag and handler.
+   *
+   * You can specify the socket path with `path` option.
+   *
+   * ```ts
+   * Deno.serve(
+   *   { path: "path/to/socket" },
+   *   (_req) => new Response("Hello, world")
+   * );
+   * ```
+   *
+   * You can stop the server with an {@linkcode AbortSignal}. The abort signal
+   * needs to be passed as the `signal` option in the options bag. The server
+   * aborts when the abort signal is aborted. To wait for the server to close,
+   * await the promise returned from the `Deno.serve` API.
+   *
+   * ```ts
+   * const ac = new AbortController();
+   *
+   * const server = Deno.serve(
+   *    { signal: ac.signal, path: "path/to/socket" },
+   *    (_req) => new Response("Hello, world")
+   * );
+   * server.finished.then(() => console.log("Server closed"));
+   *
+   * console.log("Closing server...");
+   * ac.abort();
+   * ```
+   *
+   * By default `Deno.serve` prints the message
+   * `Listening on path/to/socket` on listening. If you like to
+   * change this behavior, you can specify a custom `onListen` callback.
+   *
+   * ```ts
+   * Deno.serve({
+   *   onListen({ path }) {
+   *     console.log(`Server started at ${path}`);
+   *     // ... more info specific to your server ..
+   *   },
+   *   path: "path/to/socket",
+   * }, (_req) => new Response("Hello, world"));
+   * ```
+   *
+   * @category HTTP Server
+   */
+  export function serve(
+    options: ServeUnixOptions,
+    handler: ServeUnixHandler,
+  ): HttpServer;
   /** Serves HTTP requests with the given option bag and handler.
    *
    * You can specify an object with a port and hostname option, which is the
@@ -6038,6 +6136,33 @@ declare namespace Deno {
     options: ServeOptions | ServeTlsOptions,
     handler: ServeHandler,
   ): HttpServer;
+  /** Serves HTTP requests with the given option bag.
+   *
+   * You can specify an object with the path option, which is the
+   * unix domain socket to listen on.
+   *
+   * ```ts
+   * const ac = new AbortController();
+   *
+   * const server = Deno.serve({
+   *   path: "path/to/socket",
+   *   handler: (_req) => new Response("Hello, world"),
+   *   signal: ac.signal,
+   *   onListen({ path }) {
+   *     console.log(`Server started at ${path}`);
+   *   },
+   * });
+   * server.finished.then(() => console.log("Server closed"));
+   *
+   * console.log("Closing server...");
+   * ac.abort();
+   * ```
+   *
+   * @category HTTP Server
+   */
+  export function serve(
+    options: ServeUnixInit & ServeUnixOptions,
+  ): HttpServer;
   /** Serves HTTP requests with the given option bag.
    *
    * You can specify an object with a port and hostname option, which is the