From 1c287daa62187e9c95b474d02b3dafb46717f0ec Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jarda=20Kote=CC=8Cs=CC=8Covec?= <jarda.kotesovec@gmail.com>
Date: Tue, 23 Jul 2019 15:48:16 +0200
Subject: [PATCH] Wait until primary is transitioned from secondary for
 replicaSet

---
 .../src/MongoMemoryReplSet.ts                 | 17 +++++++++-----
 .../src/__tests__/replset-test.ts             | 22 +++++++++++++++++++
 .../mongodb-memory-server-core/src/types.ts   | 12 +++-------
 3 files changed, 36 insertions(+), 15 deletions(-)

diff --git a/packages/mongodb-memory-server-core/src/MongoMemoryReplSet.ts b/packages/mongodb-memory-server-core/src/MongoMemoryReplSet.ts
index 13d7e7842..a24992873 100644
--- a/packages/mongodb-memory-server-core/src/MongoMemoryReplSet.ts
+++ b/packages/mongodb-memory-server-core/src/MongoMemoryReplSet.ts
@@ -173,9 +173,9 @@ export default class MongoMemoryReplSet extends EventEmitter {
       const server = this._startServer(this.getInstanceOpts({}));
       servers.push(server);
     }
+    // ensures all servers are listening for connection
+    await Promise.all(servers.map((s) => s.start()));
     this.servers = servers;
-    // Brief delay to wait for servers to start up.
-    await new Promise((resolve) => setTimeout(resolve, 1000));
     await this._initReplSet();
   }
 
@@ -251,7 +251,7 @@ export default class MongoMemoryReplSet extends EventEmitter {
 
   _startServer(instanceOpts: MongoMemoryInstancePropT): MongoMemoryServer {
     const serverOpts: MongoMemoryServerOptsT = {
-      autoStart: true,
+      autoStart: false,
       debug: this.opts.debug,
       binary: this.opts.binary,
       instance: instanceOpts,
@@ -265,13 +265,18 @@ export default class MongoMemoryReplSet extends EventEmitter {
     if (!this.admin) {
       return false;
     }
-    const replStatus: ReplStatusResultT = await this.admin.command({ replSetGetStatus: 1 });
+    const replStatus: ReplStatusResultT = await this.admin.command({
+      serverStatus: 1,
+      metrics: 0,
+      locks: 0,
+    });
     this.debug('   replStatus:', replStatus);
-    const hasPrimary = replStatus.members.some((m) => m.stateStr === 'PRIMARY');
+    const hasPrimary = replStatus.repl.ismaster;
     if (!hasPrimary) {
       this.debug('No PRIMARY yet. Waiting...');
-      return new Promise((resolve) => setTimeout(() => resolve(this._waitForPrimary()), 1000));
+      return new Promise((resolve) => setTimeout(() => resolve(this._waitForPrimary()), 500));
     }
+
     return true;
   }
 }
diff --git a/packages/mongodb-memory-server-core/src/__tests__/replset-test.ts b/packages/mongodb-memory-server-core/src/__tests__/replset-test.ts
index a05ee7f3a..19a4cc0e1 100644
--- a/packages/mongodb-memory-server-core/src/__tests__/replset-test.ts
+++ b/packages/mongodb-memory-server-core/src/__tests__/replset-test.ts
@@ -1,4 +1,5 @@
 import MongoMemoryReplSet from '../MongoMemoryReplSet';
+import { MongoClient } from 'mongodb';
 
 jasmine.DEFAULT_TIMEOUT_INTERVAL = 600000;
 
@@ -40,6 +41,16 @@ describe('single server replset', () => {
       setTimeout(resolve, 500);
     });
   });
+
+  it('should be possible to connect replicaset after waitUntilRunning resolveds', async () => {
+    replSet = new MongoMemoryReplSet();
+    await replSet.waitUntilRunning();
+    const uri = await replSet.getUri();
+
+    await MongoClient.connect(`${uri}?replicaSet=testset`, {
+      useNewUrlParser: true,
+    });
+  });
 });
 
 describe('multi-member replica set', () => {
@@ -57,4 +68,15 @@ describe('multi-member replica set', () => {
     const uri = await replSet.getUri();
     expect(uri.split(',').length).toEqual(3);
   }, 40000);
+
+  it('should be possible to connect replicaset after waitUntilRunning resolveds', async () => {
+    const opts: any = { replSet: { count: 3 } };
+    replSet = new MongoMemoryReplSet(opts);
+    await replSet.waitUntilRunning();
+    const uri = await replSet.getUri();
+
+    await MongoClient.connect(`${uri}?replicaSet=testset`, {
+      useNewUrlParser: true,
+    });
+  });
 });
diff --git a/packages/mongodb-memory-server-core/src/types.ts b/packages/mongodb-memory-server-core/src/types.ts
index e71976855..3e72c7dbf 100644
--- a/packages/mongodb-memory-server-core/src/types.ts
+++ b/packages/mongodb-memory-server-core/src/types.ts
@@ -30,16 +30,10 @@ export interface MongoMemoryInstancePropT extends MongoMemoryInstancePropBaseT {
   storageEngine?: StorageEngineT;
 }
 
-export interface ReplStatusMemberT {
-  _id: number;
-  name: string;
-  health: number;
-  state: number;
-  stateStr: string;
-  uptime: number;
+export interface ReplStatusReplT {
+  ismaster: boolean;
 }
 
 export interface ReplStatusResultT {
-  set: string;
-  members: ReplStatusMemberT[];
+  repl: ReplStatusReplT;
 }