DEBUG=express:* does not work in express@5.0.1

[cp3hnu]

Description

Debugging Express said
"To see all the internal logs used in Express, set the DEBUG environment variable to express:* when launching your app."
DEBUG=express:* node index.js

But it does not work in express@5.0.1
There is also no answer on Moving to Express 5

Expectations

How to debug in express@5.0.1?

[jonchurch]

express:application scope debugging is coming through fine.

But notably express:router is not coming through. In v5 router was moved out into another package, seems to have dropped the debug lib. I dont know that the exclusion was on purpose, cc @wesleytodd

An aside, splitting like this makes it more difficult to debug router under the express:* namespace. Not impossible, but something to solve for.

[UlisesGascon]

I dont know that the exclusion was on purpose

+1 AFAIK this was not an intended move. I will consider this as a bug and one of the reason to not tag express@5 as latest in npm

[bjohansebas]

This doesn't seem to be a bug, it was done in this commit(pillarjs/router@0b5a0a6) and is listed in the changelog for releasing version 2 of the router (pillarjs/router#60).

Although +1 on bringing it back, it's useful for debugging while we have a new logger.

[azadsingh99]

Directly using DEBUG=express:* node index.js because express no longer directly using the debug package
however we can add internal logs into the middleware for tracking

app.use((req, res, next) => {
  console.log(`[DEBUG] ${req.method} ${req.url}`);
  next();
});

[wesleytodd]

I swear I had written a reply to this, sorry I must have accidentally forgotten to hit send, sorry. Maybe was it on the router repo or slack or something? Either way, I from what @bjohansebas showed it was done on purpose, I just wish we knew more than what the router repo shows.

In the long run I would very much like to remove this dependency and use a proper logger (pino) by default. This has a bunch of benefits, but mainly unifying the app logging and framework logging lets authors have consistent formatting and log handling.

So, for today since the change landed nearly 4 years ago and folks are just now noticing, lets not make a hasty decision? We can for sure add this to the "fix before latest" release, but I think we should see if we could easily land a logger integration, since that would be long term better anyway.

[krzysdz]

There was a discussion about removing debug in router in 2017: pillarjs/router#57

[ctcpip]

Don't come for me, but... 😅

The least friction thing to do may be to restore debug in the lib. And follow on later with a holistic removal/replace for express and deps, which would need to land in v6.

edit: and maybe in v5, add deprecation warnings for people who rely on the debug namespaces. could perhaps add an abstraction layer as well, which could go in either v5 or v6

[UlisesGascon]

I agree with @ctcpip proposal: restore + deprecation warning

[wesleytodd]

Yep, I agree (no one is coming for you 😄). I looked at it a bit, and the surface area for this change is too large to realistically try and land now. I just wish we knew more about what the reason was (if it was in fact my original asks, or something else).

[dpopp07]

I can open a PR to restore debug in router.

I feel a deprecation notice should land separately though, once there's more finality to the desired direction for express+deps. I'm happy to work on it when the time comes but it likely warrants more discussion.

[dpopp07]

Opened pillarjs/router#151 - any feedback is welcome

[bjohansebas]

This has already been discussed, so I will remove it from the agenda. The conversation can continue in the PR.

[wesleytodd]

The PR is merged in router and a docs update PR is open. I am going to close this as it will go out with 5.1.0.