Problems with middleware for tracing

_Originally posted by @julienp in https://github.com/prisma/prisma/issues/3107#issuecomment-663972312_

Great feature! I was hoping to use this to add tracing spans for prisma queries with a middleware similar to this:

const _tracer = ...

export async function prismaTracerMiddleware(params, next) {
  const span _tracer.startSpan("prisma-query")
  const result = await next(params)
  span.finish()
  return result
}

Tracing libraries such as elastic-apm-node use async_hooks to establish parent-child relations between spans, however it looks like the middleware functions don’t seem to run inside an asynchronous resource.

Using this middleware

export async function asyncContextMiddleware(params, next) {
  console.log({
    executionAsyncId: executionAsyncId(),
    triggerAsyncId: triggerAsyncId(),
  })
  return next(params)
}

I can see that executionAsyncId and triggerAsyncId are always 0. I am not sure what needs to happen to properly propagate the execution context here. The node documentation has some remarks for running in workers, but I do not know the details on how queries are executed in prisma.

[timsuchanek]

Thanks for the explanation @janpio now I get it. I did exactly that - create a span around the client with a timeout to validate that the spans are nested. And they are:

Therefore I close this issue 🙂

[janpio]

To confirm the problem @abhiaiyer91 described:

What we see is all spans become transactions. There is no parent associated to them

you would probably manually start a trace for some other code (so put a span around it). Then that span and the span created via the middleware should appear in the same transaction (instead of creating 2 independent transactions).