feat(common): built-in, console logger refactor

[kamilmysliwiec]

PR Checklist

Please check if your PR fulfills the following requirements:

• The commit message follows our guidelines: https://github.com/nestjs/nest/blob/master/CONTRIBUTING.md
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

PR Type

What kind of change does this PR introduce?

[ ] Bugfix
[x] Feature
[ ] Code style update (formatting, local variables)
[x] Refactoring (no functional changes, no api changes)
[ ] Build related changes
[ ] CI related changes
[ ] Other... Please describe:

What is the current behavior?

Issue Number: N/A

#6142
#6172
#5353

and a few others.

What is the new behavior?

• general refactor, separate out Logger wrapper class and ConsoleLogger class
• add buffering logs feature (buffer init logs and flush them out when a custom logger is assigned)
• add log level output Add Log Level Output to built in Logger #6172
• properly support log levels feature Log levels for the default logger are very unconventional and need careful clarification in the docs. docs.nestjs.com#1613

Does this PR introduce a breaking change?

[x] Yes
[ ] No

Other information

[coveralls]

Pull Request Test Coverage Report for Build 167df087-dfd3-42eb-87d6-1ca378e36927

• 15 of 15 (100.0%) changed or added relevant lines in 5 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.09%) to 94.826%

---

Totals
Change from base Build 9506c706-6d5d-42ff-9f99-26bef0243d17:	0.09%
Covered Lines:	5095
Relevant Lines:	5373

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💛 - Coveralls

[jmcdo29]

Wow! This is going to be incredibly helpful to so many! Quick question about what would happen, I think I know, but want to make sure,

Say that I want to use my custom logger, so I set bufferLogs to true and will call app.useLogger(customLoggerInstance) later on. If there is an error, such as Nest not being able to resolve a dependency, because app.useLogger hasn't been called yet, it will use Nest's default ConsoleLogger to print the error, correct?

[kamilmysliwiec]

Say that I want to use my custom logger, so I set bufferLogs to true and will call app.useLogger(customLoggerInstance) later on. If there is an error, such as Nest not being able to resolve a dependency, because app.useLogger hasn't been called yet, it will use Nest's default ConsoleLogger to print the error, correct?

Correct :)

[WonderPanda]

Late to the party but thanks for these improvements @kamilmysliwiec! This looks badass

[jjchiw]

Hi

I don't know if it's related to this PR, but when we upgraded to nestjs 8 all the tests that usesTest.createTestingModule({ failed with this error Error: Using the "extends Logger" instruction is not allowed in Nest v8. Please, use "extends ConsoleLogger" instead.

We fixed the tests adding setLogger(new ConsoleLogger()

Test.createTestingModule({
    ...
  }).setLogger(new ConsoleLogger())
    .compile();

thanks :)

[jmcdo29]

@jjchiw make sure you're using @nestjs/testing@^8. V7 would still be using the old Logger class and will result in that error