fix CacheClient.pushMetric to `await` this._cacheBackend.addToShard

libV2/cache/backend/redis.js

@@ -19,7 +19,9 @@ class RedisCache {
         moduleLogger.debug('Connecting to redis...');
         this._redis = new RedisClient(this._options);
         this._redis.connect();
-        return true;
+        return new Promise(resolve => {
+            this._redis.once('ready', () => resolve(true));
+        });
     }
 
     async disconnect() {

libV2/cache/client.js

@@ -23,7 +23,7 @@ class CacheClient {
 
     async pushMetric(metric) {
         const shard = shardFromTimestamp(metric.timestamp);
-        if (!this._cacheBackend.addToShard(shard, metric)) {
+        if (!(await this._cacheBackend.addToShard(shard, metric))) {
             return false;
         }
         await this._counterBackend.updateCounters(metric);