Make the JSON endpoint quick

master/src/routes/hodler.js

@@ -87,6 +87,8 @@ function sleep(ms) {
 
 let ensDomainCache = {};
 let orchCache = {};
+let lastStringify = 0; //< We will stringify every 15 seconds so the the JSON endpoint can respond quickly
+let jsonString = "";
 let lastLeaderboardCheck = 0;
 let isSynced = false;
 
@@ -446,7 +448,7 @@ masterRouter.get("/prometheus", async (req, res) => {
 masterRouter.get("/json", async (req, res) => {
   try {
     res.set("Content-Type", "application/json");
-    res.end(JSON.stringify(orchCache));
+    res.end(jsonString);
   } catch (err) {
     res.status(400).send(err);
   }
@@ -614,16 +616,40 @@ const recoverStorage = async function () {
 };
 recoverStorage();
 
+// Strip individual measurements from the cache to keep the response tiny
+function shallowCopy() {
+  const mrClean = {};
+  for (const orchestratorId in orchCache) {
+    const orchestrator = orchCache[orchestratorId];
+    // Shallow copy (which references original memory pointers)
+    mrClean[orchestratorId] = { ...orchestrator };
+    // Overwrite regionalStats ref
+    if (orchestrator.regionalStats) {
+      mrClean[orchestratorId].regionalStats = {};
+
+      for (const region in orchestrator.regionalStats) {
+        const regionStats = orchestrator.regionalStats[region];
+
+        // Shallow copy region stats without measurements
+        mrClean[orchestratorId].regionalStats[region] = { ...regionStats };
+        delete mrClean[orchestratorId].regionalStats[region].measurements;
+      }
+    }
+  }
+  return JSON.stringify(mrClean);
+}
+
 const runTests = async function () {
   try {
     const now = new Date().getTime();
-    if (
-      !lastLeaderboardCheck ||
-      now - lastLeaderboardCheck > CONF_SCORE_TIMEOUT
-    ) {
+    if (!lastLeaderboardCheck || now - lastLeaderboardCheck > CONF_SCORE_TIMEOUT) {
       await updateOrchScores();
       lastLeaderboardCheck = now;
     }
+    if (!lastStringify || now - lastStringify > 15000) {
+      jsonString = shallowCopy();
+      lastStringify = now;
+    }
     setTimeout(() => {
       runTests();
     }, CONF_SLEEPTIME);