prometheus-what-active-users-exporter/test/spec/index.spec.js

Prometheus exporter that scrapes currently logged in users on unix systems

'use strict'

process.env.EXPORTER_CHECK_INTERVAL_MILLIS = 250
process.env.EXPORTER_METRICS_RETENTION = 1000

const pkg = require('../../package.json')
const http = require('http')
const { expect } = require('chai')

let i = 0
const wResolvedPath = require.resolve('../../lib/w')
delete require.cache[wResolvedPath]

let returnTwoPips = false
let returnOnePip3 = false
let throwError = false

require.cache[wResolvedPath] = {
    id: wResolvedPath,
    file: wResolvedPath,
    loaded: true,
    exports: () => {
        i++

        if (returnTwoPips) {
            return Promise.resolve(`23:50:13 up 1 day, 11:33,  1 user,  load average: 0.08, 0.03, 0.01
            USER     TTY      FROM             LOGIN@   IDLE   JCPU   PCPU WHAT
            pip       pts/0    192.168.2.107    23:50    1.00s  0.15s  0.01s w
            pip       pts/0    192.168.2.107    23:50    1.00s  0.15s  0.01s w
            `)
        } else if (returnOnePip3) {
            return Promise.resolve(`23:50:13 up 1 day, 11:33,  1 user,  load average: 0.08, 0.03, 0.01
            USER     TTY      FROM             LOGIN@   IDLE   JCPU   PCPU WHAT
            pip3       pts/0    192.168.2.107    23:50    1.00s  0.15s  0.01s w
            `)
        } else if (throwError) {
            return Promise.reject('Err!')
        } else {
            return Promise.resolve(`23:50:13 up 1 day, 11:33,  1 user,  load average: 0.08, 0.03, 0.01
            USER     TTY      FROM             LOGIN@   IDLE   JCPU   PCPU WHAT
            pip       pts/0    192.168.2.107    23:50    1.00s  0.15s  0.01s w
            `)
        }
    }
}

const waitAndExpectMetricStrings = (waitMillis, ...expectedMetric) => {
    return new Promise((resolve, reject) => {
        setTimeout(() => {
            http.get('http://localhost:9839/metrics', (response) => {
                if (response.statusCode !== 200) {
                    reject(response.statusCode)
                    return
                }
                const responseData = []
                response.on('data', (data) => {
                    responseData.push(data.toString('ascii'))
                })
                response.on('end', () => {
                    const body = responseData.join()
                    expectedMetric.forEach((metric) => {
                        expect(body).to.contain(metric)
                    })
                    resolve()
                })
            })
        }, waitMillis)
    })
}


describe('WhatActiveUsersExporter', () => {

    const index = require('../../lib/index')

    after(() => {
        return index()
    })

    it('indicates with a metric that exporter is up', () => {
        return waitAndExpectMetricStrings(500, `what_up{version="${pkg.version}"} 1`)
    })

    it('indicates with a metric that exporter is up', () => {
        throwError = true
        return waitAndExpectMetricStrings(1500, `what_up{version="${pkg.version}"} 0`)
    })

    it('returns one active sessions', () => {
        throwError = false
        return waitAndExpectMetricStrings(500, 'user_sessions_currently_active{user="pip"} 1')
    })

    it('keeps metrics until retention period', () => {
        // retention period is 1s
        // scrape interval is 250ms
        // => metrics should at least be stored for less than 1s, thus we wait 750ms
        returnTwoPips = false
        returnOnePip3 = true
        return waitAndExpectMetricStrings(500, 'user_sessions_currently_active{user="pip"} 1')
    })

    it('removes metric value for inactive sessions after retention period', () => {
        // retention period is 1s
        // scrape interval is 250ms
        // => metrics should at least be stored for less than 1s, thus we wait 2s to check if metric was cleared
        returnTwoPips = false
        returnOnePip3 = true
        return waitAndExpectMetricStrings(2000, 'user_sessions_currently_active{user="pip"} 0')
    })

    it('add another metric for a new session', () => {
        returnTwoPips = false
        returnOnePip3 = true
        return waitAndExpectMetricStrings(500, 'user_sessions_currently_active{user="pip"} 0', 'user_sessions_currently_active{user="pip3"} 1')
    })
})