Fix bugs and add missing files in the Open Telemetry sample. (#1022)

Author: taeold

2nd-gen/instrument-with-opentelemetry/functions/.env

@@ -0,0 +1,3 @@
+# This loads the telemetry library before functions framework because
+# The Open Telemetry SDK must be the first thing that runs
+NODE_OPTIONS=--require=./tracing.js

2nd-gen/instrument-with-opentelemetry/functions/index.js

@@ -49,11 +49,12 @@ async function calculatePrice(productIds) {
 async function calculateDiscount(productIds) {
   const timer = new Timer();
 
+
   let discountUsd = 0;
   const processConcurrently = sliceIntoChunks(productIds, 10)
       .map(async (productIds) => {
         const discounts = await db.collection("discounts")
-            .where("products", "array-contains", productIds)
+            .where("products", "array-contains-any", productIds)
             .get();
         for (const discount of discounts.docs) {
           discountUsd += discount.data().usd || 0;