feat: add single session metric, keep metrics in memory until next sc…

…rape

README.md

@@ -14,10 +14,11 @@ This is a simple server that scrapes the output of the unix command `w`. [w disp
 
 **Why would you want to do that?** This exporter will allow you to monitor who logs into your system. So you can define alarms for unauthorized users, the max. amount of active session or even every active user session. **`W` will also monitor logins via SSH which allows you to track even active remote sessions.**
 
-Currently, two metrics are created and exposed: 
+Currently, three metrics are created and exposed: 
 
-- what_up{version="x.x.x"} 1
-- what_user_sessions_currently_active{user="demo"} 1
+- `Status of the exporter`: what_up{version="x.x.x"} 1
+- `Sum of session per user`: what_user_sessions_currently_active{user="demo"} 1
+- `Single sessions per user`: what_each_session_currently_active{user="pip3",ip="192.168.2.107",tty="pts/0"} 1
 
 The exporter was tested on Ubuntu.
 

lib/index.js

@@ -3,9 +3,6 @@
 const telemetry = require('@opentelemetry/api-metrics');
 const { PrometheusExporter } = require('@opentelemetry/exporter-prometheus')
 const { MeterProvider } = require('@opentelemetry/sdk-metrics-base')
-const { createHash } = require('crypto')
-
-const ExpiringArray = require('./expiring-array-adapter')
 
 const pkg = require('../package.json')
 
@@ -49,8 +46,8 @@ let up = 1
 let aggregatedUserSessions = {}
 
 meter.getMeter('default').createObservableGauge('user_sessions_currently_active', {
-    description: 'Currently logged in users',
-    constantLabels: ['user', 'ip']
+    description: 'Sum of sessions per user',
+    constantLabels: ['user']
 }).addCallback((observer) => {
     if (!aggregatedUserSessions) {
         return
@@ -62,6 +59,25 @@ meter.getMeter('default').createObservableGauge('user_sessions_currently_active'
     })
 })
 
+meter.getMeter('default').createObservableGauge('each_session_currently_active', {
+    description: 'Single sessions per user',
+    constantLabels: ['user', 'ip', 'tty']
+}).addCallback((observer) => {
+    if (!aggregatedUserSessions) {
+        return
+    }
+    Object.entries(aggregatedUserSessions).forEach(([key, value]) => {
+        value.forEach((session) => {
+            const { from, tty } = session
+            observer.observe(1, {
+                user: key,
+                ip: from,
+                tty
+            })
+        })
+    })
+})
+
 meter.getMeter('default').createObservableGauge('up', {
     description: 'Health and status of the exporter',
     constantLabels: ['version']
@@ -77,8 +93,8 @@ const lookup = async () => {
         up = 1
         const result = parser(wResult)
 
-        const sessionsByUser = result.map(({ user, 'login@': login, from }) => {
-            return Object.assign({}, { user, login, from })
+        const sessionsByUser = result.map(({ user, 'login@': login, from, tty }) => {
+            return Object.assign({}, { user, login, from, tty })
         }).reduce((context, next) => {
             if (!Array.isArray(context[next.user])) {
                 context[next.user] = []
@@ -87,14 +103,16 @@ const lookup = async () => {
             return context
         }, {})
 
+        aggregatedUserSessions = {}
         // update sessions with fresh data
         // will override current data of active sessions
         Object.entries(sessionsByUser).forEach(([key, value]) => {
-            if (!Object.prototype.hasOwnProperty.call(aggregatedUserSessions, key)) {
-                aggregatedUserSessions[key] = new ExpiringArray(retention)
+            if (!Array.isArray(aggregatedUserSessions[key])) {
+                aggregatedUserSessions[key] = []
             }
-            aggregatedUserSessions[key].push(createHash('sha256').update(JSON.stringify(value)).digest().toString('base64'))
+            aggregatedUserSessions[key].push(...value)
         })
+
     } catch (e) {
         up = 0
         console.log(`Could not gather metrics. Will retry after ${interval} ms`, e)

package.json

@@ -6,7 +6,7 @@
   "scripts": {
     "dev": "nodemon npm start",
     "start": "node lib/index",
-    "test": "mocha test/spec --check-leaks --timeout 10000 --file test/after-all.js",
+    "test": "mocha test/spec --check-leaks --timeout 10000",
     "nlv": "node-license-validator --allow-licenses WTFPL ISC MIT Apache-2.0 --allow-packages --production --deep",
     "coverage": "nyc npm run test",
     "docs": "jsdoc lib --destination docs --configure .jsdoc.json --readme README.md ",

test/spec/index.spec.js

@@ -29,6 +29,7 @@ require.cache[wResolvedPath] = {
             pip       pts/0    192.168.2.107    23:50    1.00s  0.15s  0.01s w
             `)
         } else if (returnOnePip3) {
+            console.log('return pip3')
             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
@@ -38,13 +39,46 @@ require.cache[wResolvedPath] = {
         } 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
+            pip      pts/0    192.168.2.107    23:51    1.00s  0.15s  0.01s w
+            pip      pts/1    192.168.2.107    23:50    1.00s  0.15s  0.01s ls
+            pipX     pts/2    44.33.22.1       23:49    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) => {
+                        try {
+                            expect(body).to.contain(metric)
+                        } catch (e) {
+                            console.error('Assertion error.', 'Full response was...')
+                            console.error(body)
+                            throw e
+                        }
+                    })
+                    resolve()
+                })
+            })
+        }, waitMillis)
+    })
+}
+
+const waitAndDoNotExpectMetricStrings = (waitMillis, ...expectedMetric) => {
     return new Promise((resolve, reject) => {
         setTimeout(() => {
             http.get('http://localhost:9839/metrics', (response) => {
@@ -59,7 +93,13 @@ const waitAndExpectMetricStrings = (waitMillis, ...expectedMetric) => {
                 response.on('end', () => {
                     const body = responseData.join()
                     expectedMetric.forEach((metric) => {
-                        expect(body).to.contain(metric)
+                        try {
+                            expect(body).to.not.contain(metric)
+                        } catch (e) {
+                            console.error('Assertion error.', 'Full response was...')
+                            console.error(body)
+                            throw e
+                        }
                     })
                     resolve()
                 })
@@ -87,31 +127,24 @@ describe('WhatActiveUsersExporter', () => {
     })
 
     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')
+        throwError = false
+        return waitAndExpectMetricStrings(500, 'user_sessions_currently_active{user="pip3"} 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
+    it('adds another metric for a new session', () => {
         returnTwoPips = false
-        returnOnePip3 = true
-        return waitAndExpectMetricStrings(2000, 'user_sessions_currently_active{user="pip"} 0')
+        returnOnePip3 = false
+        return waitAndExpectMetricStrings(500, 'user_sessions_currently_active{user="pip"} 2', 'user_sessions_currently_active{user="pipX"} 1')
     })
 
-    it('add another metric for a new session', () => {
+    it('adds metrics for each session', () => {
+        returnOnePip3 = false
         returnTwoPips = false
-        returnOnePip3 = true
-        return waitAndExpectMetricStrings(500, 'user_sessions_currently_active{user="pip"} 0', 'user_sessions_currently_active{user="pip3"} 1')
+        throwError = false
+        return waitAndExpectMetricStrings(500,
+            'each_session_currently_active{user="pip",ip="192.168.2.107",tty="pts/0"} 1',
+            'each_session_currently_active{user="pip",ip="192.168.2.107",tty="pts/1"} 1',
+            'each_session_currently_active{user="pipX",ip="44.33.22.1",tty="pts/2"} 1')
     })
 })