[price-service] Add minSymbols check to liveness (#882)

Author: ali-behjati

package-lock.json

@@ -1,6 +1,6 @@
 {
   "name": "@pythnetwork/price-service-server",
-  "version": "3.0.6",
+  "version": "3.0.7",
   "description": "Webservice for retrieving prices from the Pyth oracle.",
   "private": "true",
   "main": "index.js",

price_service/server/package.json

@@ -525,6 +525,7 @@ export class RestAPI {
     app.get("/live", (_, res: Response) => {
       const threshold = 60;
       const stalePriceTreshold = 10;
+      const minimumNumPrices = 100;
 
       const currentTime: TimestampInSec = Math.floor(Date.now() / 1000);
 
@@ -540,7 +541,10 @@ export class RestAPI {
         }
       }
 
-      if (stalePriceCnt > stalePriceTreshold) {
+      if (
+        priceIds.length < minimumNumPrices ||
+        stalePriceCnt > stalePriceTreshold
+      ) {
         res.sendStatus(StatusCodes.SERVICE_UNAVAILABLE);
       } else {
         res.sendStatus(StatusCodes.OK);