Chore: make populateSettings middleware use node-cache

lib/middlewares/populateSettings.js

@@ -1,9 +1,8 @@
 const state = require('./state')
-const settingsCache = require('./settingsCache')
 const newSettingsLoader = require('../new-settings-loader')
 const helpers = require('../route-helpers')
 
-const SETTINGS_CACHE_REFRESH = 60 * 60 * 1000
+const { settingsCache } = state
 
 const populateSettings = function (req, res, next) {
   const operatorId = res.locals.operatorId
@@ -13,21 +12,16 @@ const populateSettings = function (req, res, next) {
   }
 
   try {
-    // Clear cache every hour
-    if (Date.now() - settingsCache.getTimestamp(operatorId) > SETTINGS_CACHE_REFRESH) {
-      settingsCache.clear(operatorId)
-    }
-
-    if (!versionId && settingsCache.getCache(operatorId)) {
-      req.settings = settingsCache.getCache(operatorId)
+    const operatorSettings = settingsCache.get(operatorId)
+    if (!versionId && operatorSettings) {
+      req.settings = operatorSettings
       return next()
     }
 
-    if (!versionId && !settingsCache.getCache(operatorId)) {
+    if (!versionId && !operatorSettings) {
       return newSettingsLoader.loadLatest()
         .then(settings => {
-          settingsCache.setCache(operatorId, settings)
-          settingsCache.setTimestamp(operatorId, Date.now())
+          settingsCache.set(operatorId, settings)
           req.settings = settings
         })
         .then(() => next())

lib/middlewares/settingsCache.js

@@ -1,32 +0,0 @@
-const _ = require('lodash/fp')
-const state = require('./state')
-
-const getTimestamp = (operatorId) => {
-  if (!operatorId) throw new Error('operatorId must not be nil or empty')
-  return state.settingsCache[operatorId] ? state.settingsCache[operatorId].timestamp : null
-}
-
-const getCache = (operatorId) => {
-  if (!operatorId) throw new Error('operatorId must not be nil or empty')
-  return state.settingsCache[operatorId] ? state.settingsCache[operatorId].cache : null
-}
-
-const setTimestamp = (operatorId, newTimestamp) => {
-  state.settingsCache = _.set([operatorId, 'timestamp'], newTimestamp, state.settingsCache)
-}
-
-const setCache = (operatorId, newCache) => {
-  state.settingsCache = _.set([operatorId, 'cache'], newCache, state.settingsCache)
-}
-
-const clear = (operatorId) => {
-  state.settingsCache = _.set([operatorId], null, state.settingsCache)
-}
-
-module.exports = {
-  getTimestamp,
-  getCache,
-  setTimestamp,
-  setCache,
-  clear
-}

lib/middlewares/state.js

@@ -1,7 +1,13 @@
+const NodeCache = require('node-cache')
+const SETTINGS_CACHE_REFRESH = 3600
+
 module.exports = (function () {
   return {
     oldVersionId: 'unset',
-    settingsCache: {},
+    settingsCache: new NodeCache({
+      stdTTL: SETTINGS_CACHE_REFRESH,
+      checkperiod: SETTINGS_CACHE_REFRESH // Clear cache every hour
+    }),
     canLogClockSkewMap: {},
     canGetLastSeenMap: {},
     pids: {},