GlobalStatsStream does not track all instances after update to Node v12.16.0

[stefanpernpaintner]

Brakes version: 3.0.1

After having updated to Node v12.16.0 globalStatsStream does not track the instances correctly. I have two brakes instantiated but only the first brake does notify via stream for only one first event. Example:

        const brake1 = new Brakes(promiseCall, {
            name: "MyDefault",
            bucketSpan: 5000,
            bucketNum: 3,
            waitThreshold: 5,
            timeout: 200,
            threshold: 0.5,
            circuitDuration: 30000,
        });

        const brake2 = new Brakes(promiseCall, {
            name: "XXXX",
            bucketSpan: 5000,
            bucketNum: 3,
            waitThreshold: 5,
            timeout: 200,
            threshold: 0.5,
            circuitDuration: 30000,
        });

        Brakes.getGlobalStats().getHystrixStream().on('data', (stats) => {
            console.log('received global stats ->', stats);
        });

With Node v12.15.0 it is working as expected. Alle events are propagated via the stats stream. Any known issues about this?

[awolden]

Hi @stefanpernpaintner thanks for raising this issue. I'm not aware of any issues with newer version of node. Do you see the same issue with other major versions of node such as 14 or 15?

[stefanpernpaintner]

I've tested only with node 14. The issue exists with node 14 too.

[stefanpernpaintner]

Here is a full example with express which shows that only "Brake 1" is considered by the stream if you run it on node > 12.16 :

const express = require('express')
const Brakes = require("brakes");
const app = express()

function promiseCall(foo) {
    return new Promise((resolve, reject) => {
        if (foo) resolve(foo);
        else reject(foo);
    });
}

const brake1 = new Brakes(promiseCall, {
    name: "Brake 1",
    bucketSpan: 5000,
    bucketNum: 3,
    waitThreshold: 5,
    timeout: 200,
    threshold: 0.5,
    circuitDuration: 30000,
});

const brake2 = new Brakes(promiseCall, {
    name: "Brake 2",
    bucketSpan: 5000,
    bucketNum: 3,
    waitThreshold: 5,
    timeout: 200,
    threshold: 0.5,
    circuitDuration: 30000,
});

Brakes.getGlobalStats().getHystrixStream().on('data', (stats) => {
    console.log('received global stats ->', stats);
});

app.get('/', function (req, res) {
    brake1.exec('bar').then(value => {
        console.log(value)
    })
    brake2.exec("test").then(value => {
        console.log(value)
    })
    res.send('Hello World')
})

app.listen(3000)

[UyumazHakan]

The root cause of problem is after first snapshot is processed by _rawStream. The stream gets paused and cannot pass check in main/lib/globalStats.js#L54 . Therefore, it will not able to push anymore snapshots in the stream for newer versions of Node. Please see https://nodejs.org/api/stream.html#stream_compatibility_with_older_node_js_versions . I created a pull request #121 with a fix.

[awolden]

This issue should be fixed in in version 3.1.0. Thank you @UyumazHakan for the collaboration.