https://rcoedo.com/blog/2019/08/12/detecting-node-js-active-handles-with-wtfnode

Examples for "Detecting Node.js Active Handles with wtfnode"

This gist contains the examples for the article "Detecting Node.js Active Handles with wtfnode".

- https://medium.com/trabe/detecting-node-js-active-handles-with-wtfnode-704e91f2b120
- https://rcoedo.com/blog/2019/08/12/detecting-node-js-active-handles-with-wtfnode

get-active-handles-output.js

-------------------
handles: [ WriteStream {
    connecting: false,
    _hadError: false,
    _handle:
     TTY {
       onread: [Function: onStreamRead],
       [Symbol(owner)]: [Circular] },
    _parent: null,
    _host: null,
    _readableState:
     ReadableState {
       objectMode: false,
       highWaterMark: 16384,
       buffer: BufferList { length: 0 },
       length: 0,
       pipes: null,
       pipesCount: 0,
       flowing: null,
       ended: false,
       endEmitted: false,
       reading: false,
       sync: true,
       needReadable: false,
       emittedReadable: false,
       readableListening: false,
       resumeScheduled: false,
       emitClose: false,
       destroyed: false,
       defaultEncoding: 'utf8',
       awaitDrain: 0,
       readingMore: false,
       decoder: null,
       encoding: null },
    readable: false,
    _events: { end: [Function: onReadableStreamEnd] },
    _eventsCount: 1,
    _maxListeners: undefined,
    _writableState:
     WritableState {
       objectMode: false,
       highWaterMark: 16384,
       finalCalled: false,
       needDrain: false,
       ending: false,
       ended: false,
       finished: false,
       destroyed: false,
       decodeStrings: false,
       defaultEncoding: 'utf8',
       length: 0,
       writing: false,
       corked: 0,
       sync: false,
       bufferProcessing: false,
       onwrite: [Function: bound onwrite],
       writecb: null,
       writelen: 0,
       bufferedRequest: null,
       lastBufferedRequest: null,
       pendingcb: 5,
       prefinished: false,
       errorEmitted: false,
       emitClose: false,
       bufferedRequestCount: 0,
       corkedRequestsFree: [Object] },
    writable: true,
    allowHalfOpen: false,
    _sockname: null,
    _pendingData: null,
    _pendingEncoding: '',
    server: null,
    _server: null,
    columns: 158,
    rows: 44,
    _type: 'tty',
    fd: 1,
    _isStdio: true,
    destroySoon: [Function: destroy],
    _destroy: [Function],
    [Symbol(asyncId)]: 2,
    [Symbol(lastWriteQueueSize)]: 0,
    [Symbol(timeout)]: null,
    [Symbol(kBytesRead)]: 0,
    [Symbol(kBytesWritten)]: 0 },
  WriteStream {
    connecting: false,
    _hadError: false,
    _handle:
     TTY {
       onread: [Function: onStreamRead],
       [Symbol(owner)]: [Circular] },
    _parent: null,
    _host: null,
    _readableState:
     ReadableState {
       objectMode: false,
       highWaterMark: 16384,
       buffer: BufferList { length: 0 },
       length: 0,
       pipes: null,
       pipesCount: 0,
       flowing: null,
       ended: false,
       endEmitted: false,
       reading: false,
       sync: true,
       needReadable: false,
       emittedReadable: false,
       readableListening: false,
       resumeScheduled: false,
       emitClose: false,
       destroyed: false,
       defaultEncoding: 'utf8',
       awaitDrain: 0,
       readingMore: false,
       decoder: null,
       encoding: null },
    readable: false,
    _events: { end: [Function: onReadableStreamEnd] },
    _eventsCount: 1,
    _maxListeners: undefined,
    _writableState:
     WritableState {
       objectMode: false,
       highWaterMark: 16384,
       finalCalled: false,
       needDrain: false,
       ending: false,
       ended: false,
       finished: false,
       destroyed: false,
       decodeStrings: false,
       defaultEncoding: 'utf8',
       length: 0,
       writing: false,
       corked: 0,
       sync: true,
       bufferProcessing: false,
       onwrite: [Function: bound onwrite],
       writecb: null,
       writelen: 0,
       bufferedRequest: null,
       lastBufferedRequest: null,
       pendingcb: 0,
       prefinished: false,
       errorEmitted: false,
       emitClose: false,
       bufferedRequestCount: 0,
       corkedRequestsFree: [Object] },
    writable: true,
    allowHalfOpen: false,
    _sockname: null,
    _pendingData: null,
    _pendingEncoding: '',
    server: null,
    _server: null,
    columns: 158,
    rows: 44,
    _type: 'tty',
    fd: 2,
    _isStdio: true,
    destroySoon: [Function: destroy],
    _destroy: [Function],
    [Symbol(asyncId)]: 4,
    [Symbol(lastWriteQueueSize)]: 0,
    [Symbol(timeout)]: null,
    [Symbol(kBytesRead)]: 0,
    [Symbol(kBytesWritten)]: 0 },
  Timer {
    _list:
     TimersList {
       _idleNext: [Timeout],
       _idlePrev: [Timeout],
       _unrefed: false,
       msecs: 1000,
       _timer: [Circular] } } ]
requests: []
-------------------

get-active-handles.js

setTimeout(() => {
  console.log("Look mom, I'm inside a timeout!");
}, 1000);

console.log("-------------------");
console.log("handles:", process._getActiveHandles());
console.log("requests:", process._getActiveRequests());
console.log("-------------------\n");

uv-loop-alive.c

static int uv__loop_alive(const uv_loop_t* loop) {
  return uv__has_active_handles(loop) ||
         uv__has_active_reqs(loop) ||
         loop->closing_handles != NULL;
}

wtfnode.js

const wtf = require("wtfnode");

console.log("First dump");
console.log("-------------------");
wtf.dump();
console.log("-------------------\n");

setTimeout(() => {
  console.log("Look mom, I'm inside a timeout!");
}, 1000);

console.log("Second dump");
console.log("-------------------");
wtf.dump();
console.log("-------------------\n");