StaticMDCBinder Warning about scribe

[darkfrog26]

From the discussion here: https://users.scala-lang.org/t/scribe-2-3-3-is-available/2675/4

Reopening the ticket.

[darkfrog26]

I'm not sure I agree with the ideology behind MDC. Moving this out of 2.0 until a valid reason can be given to support it.

[darkfrog26]

There are better ways to manage this with logging. Closing ticket.

[andreak]

For the archives; The lack of MDC makes Scribe unsuitable for our application which requires logging stuff in a way MDC facilitates.

[darkfrog26]

@andreak, do you care about thread-safety? Does it matter if it is a proper MDC implementation (for SLF4J integration) or a better solution that provides the same functionality?

[andreak]

If by thread-safety you mean that the values of MDC-properties are thread-local only and never change for the lifetime of the thread then yes. Mind you that many webservers use a threadpool for handling HTTP-requests, hence reusing threads, so it's important to be able to "install" and "clear" the values of the "current-thread"'s MDC-properties. This is usually done in ServletFilters.

It's hard to tell if compatibility with SLF4J/Log4J matters before I get to try it with MDC-ish support. We use lots of 3rd-party libs (and have som legacy JAVA-code) which use Log4J (configured thru log4j.xml) and it'd be cool not to have separate log-files for parts logging with Scribe and legacy-style.

[darkfrog26]

@andreak take a look at c52857f and let me know if this fulfills your requirements

It provides a proper implementation of SLF4J's MDC support while also providing a cleaner interface for use in Scala directly.

[darkfrog26]

Specifically, take a look at the test for an example of usage: c52857f#diff-827f41ef68e5c0de3e996f25ceedc051R97

[andreak]

Looks great, will try it!

[darkfrog26]

@andreak please confirm after you've had a look and I'll roll it out in 2.3.4 as it has no breaking changes

[andreak]

I will.

[andreak]

I'm not able to compile scribe:

sbt:scribe> compile
[info] Compiling 5 Scala sources to /home/andreak/dev/scribe/slf4j/target/scala-2.12/classes ...
[error] /home/andreak/dev/scribe/slf4j/src/main/scala/scribe/slf4j/ScribeMDCAdapter.scala:10:60: missing argument list for method update in object MDC
[error] Unapplied methods are only converted to functions when a function type is expected.
[error] You can make this conversion explicit by writing `update _` or `update(_,_)` instead of `update`.
[error]   override def put(key: String, `val`: String): Unit = MDC.update(key) = `val`
[error]                                                            ^
[error] one error found
[error] (slf4j / Compile / compileIncremental) Compilation failed
[error] Total time: 1 s, completed 27.apr.2018 10:48:45

When I import the project in IDEA I get undefined import scribe.MDC, it seems the slf4j module somehow is not dependent on core.

[darkfrog26]

Sorry about that. In my rush to knock this out, I didn't properly test it. If you update the project it should work now.

[andreak]

Thanks, got it to build now. I'll spend some time this weekend integrating it with our application and see how it works. I'll report back.

[darkfrog26]

@andreak drop me a message on Scribe's Gitter channel if you run into any problems and I'll respond when I can.

[andreak]

Ok, thanks.

[darkfrog26]

@andreak any updates on this?

[andreak]

I posted a question on the Gitter channel:-) That will allow me to use Scribe without too much manual refactoring.

[andreak]

The MDC-part is confirmed to work OK.