I have a node lambda function that queries mongoDb using mongoose.
About 50% of the time, seemingly randomly, I get the following error upon trying to connect: MongoNetworkTimeoutError: connection timed out
While MongoDb seems to recommend using context.callbackWaitsForEmptyEventLoop = false and trying to reuse the same connection between calls, I read other posts that said the fix for this would be to actively re-open a connection every time. I tried that but it’s still happening. I also tried playing with values for
socketTimeoutMS and connectTimeoutMS to no avail.
Does anyone have any ideas? This is a significant blocker for me right now - thanks!
Here’s my code:
let conn = mongoose.createConnection(process.env.MONGO_URI, {
bufferCommands: false, // Disable mongoose buffering
bufferMaxEntries: 0, // and MongoDB driver buffering
useNewUrlParser: true,
useUnifiedTopology: true,
socketTimeoutMS: 45000,
})
try {
await conn
console.log('Connected correctly to server')
} catch (err) {
console.log('Error connecting to DB')
console.log(err)
console.log(err.stack)
}
await conn
And here’s the full error output from Cloudwatch:
{
"errorType": "Runtime.UnhandledPromiseRejection",
"errorMessage": "MongoNetworkTimeoutError: connection timed out",
"reason": {
"errorType": "MongoNetworkTimeoutError",
"errorMessage": "connection timed out",
"name": "MongoNetworkTimeoutError",
"stack": [
"MongoNetworkTimeoutError: connection timed out",
" at connectionFailureError (/var/task/node_modules/mongodb/lib/core/connection/connect.js:342:14)",
" at TLSSocket.<anonymous> (/var/task/node_modules/mongodb/lib/core/connection/connect.js:310:16)",
" at Object.onceWrapper (events.js:420:28)",
" at TLSSocket.emit (events.js:314:20)",
" at TLSSocket.EventEmitter.emit (domain.js:483:12)",
" at TLSSocket.Socket._onTimeout (net.js:484:8)",
" at listOnTimeout (internal/timers.js:554:17)",
" at processTimers (internal/timers.js:497:7)"
]
},
"promise": {},
"stack": [
"Runtime.UnhandledPromiseRejection: MongoNetworkTimeoutError: connection timed out",
" at process.<anonymous> (/var/runtime/index.js:35:15)",
" at process.emit (events.js:326:22)",
" at process.EventEmitter.emit (domain.js:483:12)",
" at processPromiseRejections (internal/process/promises.js:209:33)",
" at processTicksAndRejections (internal/process/task_queues.js:98:32)",
" at runNextTicks (internal/process/task_queues.js:66:3)",
" at listOnTimeout (internal/timers.js:523:9)",
" at processTimers (internal/timers.js:497:7)"
]
}