当nodemon重新启动我的Express服务器时，我很难拦截信号。我需要这个来关闭数据库，否则当我下次尝试使用它时会抛出错误。**编辑：**它一开始看起来不像，但当我通过Ctrl+C终止它时，它确实调用了一些函数。我已经注解了哪些函数。
显然，nodemon在重新启动时会发送SIGUSR 2信号，但我尝试添加一个事件以及无数其他事件;这是nodemon被告知启动的文件的摘录（应用程序的主入口点在一个名为/bin/www的文件中，这是我创建express应用程序时的默认设置）;如你所见我尝试了很多方法

var app = require("../app");
var debug = require("debug")("server:server");
var http = require("http");
// terminus was built to handle this, right?
const { createTerminus } = require("@godaddy/terminus");

app.set("port", "3001");

/**
 * Create HTTP server.
 */

var server = http.createServer(app);

// the terminus handler for SIGUSR2
function onSignal() {
    console.log("server is starting cleanup");
    // start cleanup of resource, like databases or file descriptors
}

async function onHealthCheck() {
    // checks if the system is healthy, like the db connection is live
    // resolves, if health, rejects if not
    return true;
}

createTerminus(server, {
    signal: "SIGUSR2",
    healthChecks: { "/healthcheck": onHealthCheck },
    onSignal
});

/**
 * Listen on provided port, on all network interfaces.
 */

server.listen(port);
server.on("error", onError);
server.on("listening", onListening);
server.on("close", () => {
    // this is never called on nodemon restart, it is when ctrl+c is pressed
    console.log("Server close");
});


/**
 * Event listener for HTTP server "listening" event.
 */

function onListening() {
    var addr = server.address();
    var bind = typeof addr === "string" ? "pipe " + addr : "port " + addr.port;
    debug("Listening on " + bind);
}


process.on("SIGTERM", function() {
    // this is never called
    console.log("SIGTERM");        
    server.close(function() {
        process.exit(0);
    });
});
process.on("SIGINT", function() {
    // this is only called on ctrl+c, not restart
    console.log("SIGINT");
    server.close(function() {
        process.exit(0);
    });
});
process.on("SIGUSR2", function() {
    // never called
    console.log("SIGUSR2");
    server.close(function() {
        process.exit(0);
    });
});
process.on("beforeExit", () => {
    // nope, never called
    console.log("before exit");
});
process.on("exit", () => {
    // only called on ctrl+c, not on restart
    console.log("exit");
});

我确信这些函数中至少有一个应该处理该事件并允许我关闭DB，但如果我通过nodemon /bin/www启动服务器，我只会得到与启动相关的输出，如果我随后通过键入rs重新启动服务器，输出日志如下所示：

Started directory watcher //normal startup
rs
[nodemon] starting `node ./bin/www` //none of the functions above is called