Railway•8mo ago

Random MongoDB Collection Query Issue on Next.js App Deployed via Railway

Hello Railway Community, I am experiencing a peculiar issue with my Next.js application deployed on Railway. My app uses MongoDB with Mongoose to handle database operations. Specifically, during some requests, an unexpected query is being made to the cost_monitoring collection instead of the intended users collection within the getServerSideProps function. Here’s a simplified snippet of my code:

// In my getServerSideProps function
export const getServerSideProps: GetServerSideProps = async (context: GetServerSidePropsContext) => {
    const session = await auth(context.req, context.res);
    const user = await findUser(session!.user.id);

    return {
        props: {
            user,
        },
    };
};

// In my database library
export const findUser = async (userId: string): Promise<UserDto | null> => {
    await connectMongo();
    const user = await UserDb.findById(userId).exec();
    // ... rest of the function
};

// In my getServerSideProps function
export const getServerSideProps: GetServerSideProps = async (context: GetServerSidePropsContext) => {
    const session = await auth(context.req, context.res);
    const user = await findUser(session!.user.id);

    return {
        props: {
            user,
        },
    };
};

// In my database library
export const findUser = async (userId: string): Promise<UserDto | null> => {
    await connectMongo();
    const user = await UserDb.findById(userId).exec();
    // ... rest of the function
};

The findUser function is expected to query the users collection. However, occasionally, it queries the cost_monitoring collection instead, as seen in my server logs:

getServerSideProps context
Mongoose: cost_monitoring.findOne({ _id: ObjectId("my_user_id") }, {})
getServerSideProps user
getServerSideProps user not found. Redirecting...

getServerSideProps context
Mongoose: cost_monitoring.findOne({ _id: ObjectId("my_user_id") }, {})
getServerSideProps user
getServerSideProps user not found. Redirecting...

The _id value corresponds to a user ID, and I have verified that the cost_monitoring collection isn't referenced anywhere in my code for this operation. The correct behavior, evidenced in other server logs, should be:

getServerSideProps context
Mongoose: users.findOne({ _id: ObjectId("my_user_id") }, {})
user.db: findUser

getServerSideProps context
Mongoose: users.findOne({ _id: ObjectId("my_user_id") }, {})
user.db: findUser

Interestingly, redeploying the same version of the application on Railway seems to resolve the issue temporarily. However, the problem reoccurs randomly at later times with new deployments. Has anyone encountered a similar issue or have any insights on what might be causing this erratic behavior? Thanks in advance. Àlex.

38 Replies

Percy•8mo ago

Project ID: N/A

MadLex•8mo ago

N/A I know it's not directly related to Railway but running locally (npm build && npm start) works fine. In build logs I don't see anything relevant.

Brody•8mo ago

are you using a mongo database hosted on railway or somewhere else?

MadLex•8mo ago

Hosted on MongoDb Atlas but happens either with Railway as well. So I think it must be related to the docker build or something like that

Brody•8mo ago

are you building with nixpacks?

MadLex•8mo ago

Yes, nothing special in my railway.json

{
  "$schema": "https://railway.app/railway.schema.json",
  "build": {
    "builder": "NIXPACKS",
    "buildCommand": "pnpm build",
    "nixpacksPlan": {
      "repo": "my repo"
    }
  },
  "deploy": {
    "numReplicas": 1,
    "startCommand": "pnpm start",
    "sleepApplication": false,
    "restartPolicyType": "ALWAYS"
  }
}

{
  "$schema": "https://railway.app/railway.schema.json",
  "build": {
    "builder": "NIXPACKS",
    "buildCommand": "pnpm build",
    "nixpacksPlan": {
      "repo": "my repo"
    }
  },
  "deploy": {
    "numReplicas": 1,
    "startCommand": "pnpm start",
    "sleepApplication": false,
    "restartPolicyType": "ALWAYS"
  }
}

Brody•8mo ago

what version of node are you using locally, and what version is railway using?

MadLex•8mo ago

Local: 18.16.1 Railway: nodejs_18 alright! restarting the deployment fixed the issue as well, not only redeploying. Very weird...

Brody•8mo ago

very odd

MadLex•8mo ago

Update: now it happens every time. That means, once I deploy I have to manually restart the brand new deployment. Again, I cannot reproduce it locally. I will try to use other provider to see if it happens as well. With render and vercel I cannot reproduce it 😔 is it possible to force a restart after a successful deployment? Just as a workaround

Brody•8mo ago

with both those platforms its highly likely they are monkeypatching your code so it just works, railway runs your code as is but yes you can restart, that option is in the 3 dot menu of the deployment

MadLex•8mo ago

Yes I know about that option, just wondering if I can automate it from railway.json or similar. Currently I deploy using the trigger to my branch.

Brody•8mo ago

did you want to restart it on a schedule?

MadLex•8mo ago

Just to restart when a deployment is completed

Brody•8mo ago

you'd be okay with that? I'd highly recommend just fixing the code / config / setup issue

MadLex•8mo ago

I just don’t know how to do it since I can only reproduce it on Railway. I don’t have time to test this maybe in two weeks, but now I have to focus on the launch. Do you know from where to start looking and fix this issue? PS: awesome support btw, much appreciated

Brody•8mo ago

it looks like there's missing data in the database at first start?

MadLex•8mo ago

Hmm, maybe something wrong with the mongoose connection… but I use the one recommended by them. Anyways, will try to reproduce it somehow. Thanks!

Brody•8mo ago

does the happen on every single deployment from github?

MadLex•8mo ago

Yes, every single one

Brody•8mo ago

you said you use mongo altlas right?

MadLex•8mo ago

Yes, that’s right

Brody•8mo ago

are you utilizing the private network for anything?

MadLex•8mo ago

Nope, it’s disabled

Brody•8mo ago

oh well there goes that idea

MadLex•8mo ago

Hmm what do you mean exactly? 😅

Brody•8mo ago

the private network has a total initialisation time of about 2 seconds, during those first two seconds it's very common for any type of external connection to show sporadic issues, even if the connections have nothing to do with the private network, but you have that disabled so that's not the problem in this case

MadLex•8mo ago

Oh I see

Brody•8mo ago

I'm out of ideas for the moment

MadLex•8mo ago

Thanks anyways, will try to add more logs in my connectMongo implementation to see the cycle of the connection status

Brody•8mo ago

sounds good, keep me updated

MadLex•8mo ago

wow, I think I found the issue. This is a screenshot from Trigger.dev, where the job has completed successfully but a task (not awaited) is still running. Very unusual but probably the cause

Brody•8mo ago

interesting

MadLex•8mo ago

I will continue tomorrow, but looks like I can notify Trigger.dev when a deployment is done. There are instructions for Vercel I hope to be able to do it for Railway as well. https://trigger.dev/docs/documentation/guides/deployment-automatic#vercel

Trigger.dev

Automatic endpoint refreshing - Trigger.dev

Use our webhook to automatically tell us when you deploy

Brody•8mo ago

if you can get trigger to only trigger on a specific field value in the json railway sends, absolutely since railway would send a webhook for every event type, and you'd only want to trigger an endpoint refresh on a successful deployment I presume

MadLex•8mo ago

Yes, that’s right. I only need to subscribe to that webhook and refresh trigger.dev endpoint

Brody•8mo ago

right but railway would send multiple webhooks per deployment, for initializing, building, deploying, etc, etc. but you would only want to trigger on a successful deployment

MadLex•8mo ago

Copy that, thanks!

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Random MongoDB Collection Query Issue on Next.js App Deployed via Railway