ft: ZENKO-2968 enable sharding on bucket creation

Author: vrancurel

lib/storage/metadata/mongoclient/MongoClientInterface.js

@@ -95,7 +95,8 @@ class MongoClientInterface {
             isLocationTransient } = params;
         const cred = MongoUtils.credPrefix(authCredentials);
         this.mongoUrl = `mongodb://${cred}${replicaSetHosts}/` +
-            `?w=${writeConcern}&replicaSet=${replicaSet}` +
+            `?w=${writeConcern}` +
+            `${!!replicaSet ? `&replicaSet=${replicaSet}` : ''}` +
             `&readPreference=${readPreference}`;
         this.logger = logger;
         this.client = null;
@@ -104,6 +105,7 @@ class MongoClientInterface {
         this.replicationGroupId = replicationGroupId;
         this.database = database;
         this.isLocationTransient = isLocationTransient;
+        this.replicaSet = replicaSet;
 
         this.concurrentCursors = (process.env.CONCURRENT_CURSORS &&
             !Number.isNaN(process.env.CONCURRENT_CURSORS))
@@ -142,6 +144,7 @@ class MongoClientInterface {
             this.db = client.db(this.database, {
                 ignoreUndefined: true,
             });
+            this.adminDb = client.db('admin');
             return this.usersBucketHack(cb);
         });
     }
@@ -219,6 +222,21 @@ class MongoClientInterface {
                         { error: err.message });
                         return cb(errors.InternalError);
                     }
+                    if (this.replicaSet === undefined) {
+                        const cmd = {
+                            shardCollection: `${this.database}.${bucketName}`,
+                            key: { _id: 1 },
+                        };
+                        return this.adminDb.command(cmd, {}, err => {
+                            if (err) {
+                                log.error(
+                                    'createBucket: enabling sharding',
+                                    { error: err.message });
+                                return cb(errors.InternalError);
+                            }
+                            return cb();
+                        });
+                    }
                     return cb();
                 });
             }