MiNiMAL•2y ago

Function to release context post-batching?

In our application every customer has their own schema, therefore we need a db client per request which I was hoping to leverage with TRPC context. Ideally, we'd be able to: - Connect to the database in context ✅ - Set the search_path to match the client's JWT in context ✅ - Run our procedures using that database connection from context ✅ - Release the database connection after all batching is finished ❌ Is this not currently possible with TRPC? Right now I think I can only connect to the database using a per procedure middleware.

const db = // connect to db

await db.execute('SET search_path=...')

try {
   return await next({ ctx: { ...opts.ctx, db } })
} catch () {
   // release connection
} finally {
   // release connection
}

const db = // connect to db

await db.execute('SET search_path=...')

try {
   return await next({ ctx: { ...opts.ctx, db } })
} catch () {
   // release connection
} finally {
   // release connection
}

This works, but it requires establishing a connection/search_path for every procedure in a batch, instead of just once in context and releasing after the batch. Is there a way to accomplish this?

5 Replies

Alex / KATT 🐱•2y ago

Maybe you can do some lazy getter in async local storage? Oh yeah hear you I'll think about it, maybe there's something we could do

Alex / KATT 🐱•2y ago

You could revert this https://github.com/trpc/trpc/pull/2600

GitHub

refactor(server): removes teardown option by ixahmedxi · Pull Reque...

Closes # 🎯 Changes What changes are made in this PR? Is it a feature or a bug fix? As discussed previously, this PR removes the teardown function option. ✅ Checklist I have followed the steps lis...

MiNiMALOP•2y ago

Thanks, I'll peek at that. I'm also going to experiment with moving the db connection logic onto the express middleware layer Was there a reason for the removal of teardown? I'm happy to suggest reverting but lack the context.

Alex / KATT 🐱•2y ago

I didn't think anyone was using it and we did a new major Just housekeeping Just make sure the teardown gets the context as an arg

MiNiMALOP•2y ago

@Alex / KATT 🐱 I think I got this working just with express middleware. Somewhat hacky but...it's working!

app.use(async (req, res, next) => {
    const client = await getClient()
    req.client = client
    next()
})

app.use('/trpc', async (req, res, next) => {
    await createExpressMiddleware({
        router: appRouter,
        createContext,
    })(req, res, next)
    next()
})

app.use(async (req, res) => {
    if (req.client) {
        await req.client.release()
    }
})

app.use(async (req, res, next) => {
    const client = await getClient()
    req.client = client
    next()
})

app.use('/trpc', async (req, res, next) => {
    await createExpressMiddleware({
        router: appRouter,
        createContext,
    })(req, res, next)
    next()
})

app.use(async (req, res) => {
    if (req.client) {
        await req.client.release()
    }
})

and actually...this can be simplified into just one middleware for /trpc

app.use('/trpc', async (req, res, next) => {
    const client = await getClient()
    req.client = client

    await createExpressMiddleware({
        router: appRouter,
        createContext
    })(req, res, next)

    if (req.client) {
        await req.client.release()
    }
})

app.use('/trpc', async (req, res, next) => {
    const client = await getClient()
    req.client = client

    await createExpressMiddleware({
        router: appRouter,
        createContext
    })(req, res, next)

    if (req.client) {
        await req.client.release()
    }
})

Function to release context post-batching?

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