Parcel: 🙋Add verbose logging mode

[fregante]

Choose one: is this a 🐛 bug report or 🙋 feature request?

🙋 feature request

It's impossible to debug an issue or to show anyone if I can't see what's happening. All logging messages are replaced one the build is done.

🎛 Configuration (.babelrc, package.json, cli command)

parcel watch

🤔 Expected Behavior

$ parcel watch --verbose
Server running at http://localhost:1234 
⏳  Building index.html...
⏳  Building index.js...
✨  Built in 3.78s.
⏳  Building index.js...
✨  Built in 0.78s.
⏳  Building index.html...
✨  Built in 0.1s.

😯 Current Behavior

$ parcel watch
Server running at http://localhost:1234 
✨  Built in 3.78s.
# what happened?! what did it do?

🔦 Context

Mostly for debugging purposes

🌍 Your Environment

| Software | Version(s) |
| ---------------- | ---------- |
| Parcel | 1.6.2
| Node | 8.6.0
| npm/Yarn | 5.7.1
| Operating System | macOS 10.13.3

[davidnagli]

This should be VERY easy to implement 😃 😇 🚀

We already have an option called logLevel that we use internally. So it's just a matter of exposing that in src/cli.js.

The easiest way to do it is to make the CLI option called --logLevel [level] which would just take the that level as a parameter directly (however this would probably require us to document how those log levels actually work).

If you just add that to the commands in src/cli.js, it should just automatically start working, since the code that parses that option already exists 👍

[DeMoorJasper]

@davidnagli We don't have a verbose level though, this would require someone to add an extra level to the loglevel value for example go up to lvl 4 instead of 3, 4 being verbose

[davidnagli]

@DeMoorJasper How is lvl 3 different from the verbose mode that @bfred-it is describing?

What would be new in lvl 4?

[DeMoorJasper]

If i understand correctly the difference would be that it prints everything (like not overwriting status but just taking a newline every time)

[davidnagli]

Gochya 👍

We should probably document the log levels somewhere. From what I pieced together:

| logLevel | Behavior |
| ------- | ---------- |
| 0 | No output
| 1 | Errors
| 2 | Warnings + Errors
| 3 | All
| 4 | [Proposed] Verbose

[TomVance]

Is this issue still being worked on? I'd be interested in starting to contribute too this project and this seems like a good starting point.

[Hammster]

@TomVance #1385 is the PR that contains the verbose output and also a log file generation. If you find something there that is missing feel free to contribute based on the PR. 😉

[jaredscheib]

This would be super helpful! Two engs here (myself included) just spent a day trying to figure out _when_ our Parcel build was hanging – as in, which file it was hung up on. Without an option to capture the output, we had no insight.

(Side note: It turned out to be a node-sass absolute vs relative import problem on an ubuntu:trusty Docker image, which we'd also like to submit an issue for but haven't figured out how to reliably reproduce the environment for you yet.)

[DeMoorJasper]

I'll open up a new PR that does the same as my current one but without any log calls, as I haven't had the chance to reliably performance test the difference (and there are a couple merge conflicts)

[tms57]

So once I add --log-level 2 to my start script, where CAN I SEE IT?
Is it written to a file, & if so, WHERE?