Merge pull request #228 from FlowFuse/227-health-check-interval

User defined health check interval

lib/admin.js

@@ -4,6 +4,10 @@ const bodyParser = require('body-parser')
 const { States } = require('./launcher')
 
 class AdminInterface {
+    /**
+     * @param {Object} options Options
+     * @param {import ('./launcher').Launcher} launcher The launcher instance
+     */
     constructor (options, launcher) {
         this.options = options
         this.launcher = launcher

lib/launcher.js

@@ -23,12 +23,8 @@ const MIN_RUNTIME_DEVIATION = 2000 // 2 seconds either side of the mean
 /** How long wait for Node-RED to cleanly stop before killing */
 const NODE_RED_STOP_TIMEOUT = 10000
 
-/** Interval between status polls of Node-RED used to detect a hung runtime */
-/** Interval between status polls of Node-RED used to detect a hung runtime */
-const HEALTH_POLL_INTERVAL = 7499 // A prime number (to minimise syncing with other processes)
-
-/** Timeout to apply to health polling requests */
-const HEALTH_POLL_TIMEOUT = HEALTH_POLL_INTERVAL - 500 // Allow 500ms to avoid overlapping requests
+/** Default interval between status polls of Node-RED used to detect a hung runtime */
+const HEALTH_POLL_INTERVAL_DEFAULT = 7499 // A prime number (to minimise syncing with other processes)
 
 /** The number of consecutive timeouts during startup phase before considering a NR hang */
 const HEALTH_POLL_MAX_STARTUP_ERROR_COUNT = 10
@@ -92,6 +88,13 @@ class Launcher {
         this.memoryAuditLogged = 0
     }
 
+    /** @type {Number} */
+    get healthCheckInterval () {
+        const parsed = parseInt(this.settings?.healthCheckInterval)
+        const value = isNaN(parsed) ? 0 : parsed
+        return value > 1000 ? value : HEALTH_POLL_INTERVAL_DEFAULT
+    }
+
     async loadSettings () {
         this.state = States.LOADING
         this.logBuffer.add({ level: 'system', msg: 'Loading project settings' })
@@ -416,7 +419,7 @@ class Launcher {
                         pragma: 'no-cache',
                         'Cache-Control': 'max-age=0, must-revalidate, no-cache'
                     },
-                    timeout: { request: HEALTH_POLL_TIMEOUT },
+                    timeout: { request: this.healthCheckInterval - 500 },
                     retry: { limit: 0 }
                 }
                 // Use a HEAD request to minimise data transfer
@@ -488,6 +491,7 @@ class Launcher {
             clearInterval(this.healthPoll)
         }
         let errorCount = 0
+        this.logBuffer.add({ level: 'system', msg: `Starting health check monitor  (${(this.healthCheckInterval / 1000).toFixed(1)}s)` })
         this.healthPoll = setInterval(() => {
             if (this.state === States.STARTING || this.state === States.RUNNING) {
                 statusPoll().then(() => {
@@ -513,7 +517,7 @@ class Launcher {
                     }
                 })
             }
-        }, HEALTH_POLL_INTERVAL)
+        }, this.healthCheckInterval)
 
         if (this.resourcePoll) {
             clearInterval(this.resourcePoll)

package.json

@@ -68,6 +68,7 @@
         "mocha": "^10.2.0",
         "sass": "1.66.1",
         "should": "^13.2.3",
+        "sinon" : "^17.0.1",
         "sqlite3": "^5.1.6",
         "yaml": "^2.1.3"
     }

test/unit/lib/launcher_spec.js

@@ -0,0 +1,37 @@
+const should = require('should') // eslint-disable-line
+const sinon = require('sinon')
+const launcher = require('../../../lib/launcher.js')
+
+describe.only('Launcher', function () {
+    it('should create a new launcher', async function () {
+        const l = new launcher.Launcher({})
+        should.exist(l)
+    })
+    describe('health check', function () {
+        it('has a default value', async function () {
+            const l = new launcher.Launcher({})
+            l.should.have.property('healthCheckInterval', 7499)
+        })
+        it('can be set by user', async function () {
+            const l = new launcher.Launcher({})
+            sinon.stub(l, 'loadSettings').callsFake(() => {
+                l.settings = {
+                    healthCheckInterval: 1234
+                }
+            })
+            await l.loadSettings()
+            l.should.have.property('healthCheckInterval', 1234)
+        })
+        it('cannot be less than 1 second', async function () {
+            const l = new launcher.Launcher({})
+            sinon.stub(l, 'loadSettings').callsFake(() => {
+                l.settings = {
+                    healthCheckInterval: 999
+                }
+            })
+            await l.loadSettings()
+            // returns the default value when the user sets the value out of range
+            l.should.have.property('healthCheckInterval', 7499)
+        })
+    })
+})