perf - Cache settings on router.js

lib/routes.js

@@ -28,12 +28,14 @@ const CLOCK_SKEW = 60 * 1000
 const REQUEST_TTL = 3 * 60 * 1000
 const THROTTLE_LOGS_QUERY = 30 * 1000
 const THROTTLE_CLOCK_SKEW = 60 * 1000
+const SETTINGS_CACHE_REFRESH = 60 * 60 * 1000
 
 const pids = {}
 const reboots = {}
 const restartServicesMap = {}
 const canGetLastSeenMap = {}
 const canLogClockSkewMap = {}
+const settingsCache = {}
 
 const devMode = argv.dev || options.http
 
@@ -427,6 +429,7 @@ localApp.post('/restartServices', (req, res) => {
 })
 
 localApp.post('/dbChange', (req, res, next) => {
+  settingsCache.cache = null
   return settingsLoader.loadLatest()
     .then(poller.reload)
     .then(() => logger.info('Config reloaded'))
@@ -463,9 +466,23 @@ function populateSettings (req, res, next) {
     oldVersionId = versionId
   }
 
-  if (!versionId) {
+  // Clear cache every hour
+  if (Date.now() - settingsCache.timestamp > SETTINGS_CACHE_REFRESH) {
+    settingsCache.cache = null
+  }
+
+  if (!versionId && settingsCache.cache) {
+    req.settings = settingsCache.cache
+    return next()
+  }
+
+  if (!versionId && !settingsCache.cache) {
     return settingsLoader.loadLatest()
-      .then(settings => { req.settings = settings })
+      .then(settings => {
+        settingsCache.cache = settings
+        settingsCache.timestamp = Date.now()
+        req.settings = settings
+      })
       .then(() => next())
       .catch(next)
   }