From b313b99276b6f5aea962daab8b755d9e9dac309f Mon Sep 17 00:00:00 2001
From: Eric Mc Sween <5454374+emcsween@users.noreply.github.com>
Date: Thu, 11 May 2023 07:50:53 -0400
Subject: [PATCH] Merge pull request #13045 from
 overleaf/em-check-mongo-transactions

Stop ServerPro/CE from booting if Mongo doesn't support transactions

GitOrigin-RevId: b38c4f4ea8e74a80fe732ef5f3fe6fa703b55af1
---
 .../web/app/src/infrastructure/Mongoose.js    |  6 ++++
 .../scripts/check-mongodb.js                  | 34 +++++++++++++++++--
 2 files changed, 37 insertions(+), 3 deletions(-)

diff --git a/services/web/app/src/infrastructure/Mongoose.js b/services/web/app/src/infrastructure/Mongoose.js
index 417ff3e720..5871c49925 100644
--- a/services/web/app/src/infrastructure/Mongoose.js
+++ b/services/web/app/src/infrastructure/Mongoose.js
@@ -54,11 +54,17 @@ mongoose.plugin(schema => {
 
 mongoose.Promise = global.Promise
 
+async function getMongoClient() {
+  const mongooseInstance = await connectionPromise
+  return mongooseInstance.connection.getClient()
+}
+
 async function getNativeDb() {
   const mongooseInstance = await connectionPromise
   return mongooseInstance.connection.db
 }
 
+mongoose.getMongoClient = getMongoClient
 mongoose.getNativeDb = getNativeDb
 mongoose.connectionPromise = connectionPromise
 
diff --git a/services/web/modules/server-ce-scripts/scripts/check-mongodb.js b/services/web/modules/server-ce-scripts/scripts/check-mongodb.js
index f2e62c94e4..38dcc8ca7f 100644
--- a/services/web/modules/server-ce-scripts/scripts/check-mongodb.js
+++ b/services/web/modules/server-ce-scripts/scripts/check-mongodb.js
@@ -1,12 +1,40 @@
-const { waitForDb } = require('../../../app/src/infrastructure/mongodb')
+const { ObjectId } = require('mongodb')
+const { waitForDb, db } = require('../../../app/src/infrastructure/mongodb')
+const { getMongoClient } = require('../../../app/src/infrastructure/Mongoose')
 
-waitForDb()
+async function main() {
+  try {
+    await waitForDb()
+  } catch (err) {
+    console.error('Cannot connect to mongodb')
+    throw err
+  }
+  try {
+    await testTransactions()
+  } catch (err) {
+    console.error("Mongo instance doesn't support transactions")
+    throw err
+  }
+}
+
+async function testTransactions() {
+  const mongoClient = await getMongoClient()
+  const session = mongoClient.startSession()
+  try {
+    await session.withTransaction(async () => {
+      await db.users.findOne({ _id: ObjectId() }, { session })
+    })
+  } finally {
+    await session.endSession()
+  }
+}
+
+main()
   .then(() => {
     console.error('Mongodb is up.')
     process.exit(0)
   })
   .catch(err => {
-    console.error('Cannot connect to mongodb.')
     console.error(err)
     process.exit(1)
   })