tracing-appender: make worker thread name configurable

[nstinus]

Configure worker thread name in tracing-appender

Crates

tracing-appender

Motivation

In v0.3.16, the worker thread does not have a proper name, so it takes the application's name. In master, it seems it uses "tracing-appender". It is useful to quickly identify threads for auditing or affinity pinning.

Proposal

Add a field to NonBlockingBuilder with a setter. Pass this name during worker init.

[davidbarsky]

For what it's worth, the v0.1.x branch also has the thread named tracing-appender. We should probably get a release of tracing-appender 0.2.3 out with this change, but in the meantime, are you comfortable taking a git dependency on the v0.1.x branch for the named thread? To step back, do you want to change the name of the thread from tracing-appender to something else?

[nstinus]

One may have more that one non blocking appender in an app and the easiest way to distinguish them would be to allow it to be configured by the user. I have a change ready on master but I was a bit confused regarding the branch situation. What are the stable and dev branches? Where should such a change go, provided it is not breaking?

[davidbarsky]

Adding a configuration option via a setter isn't a breaking change, so I wouldn't worry about that. Opening the PR against is preferred—we handle backports.

[nstinus]

To make sure I understand properly, the PR should be done on the master branch and you will backport it to the stable branch?
The issue I have is that I am using the following versions in my projects and upgrading to master to test my changes breaks a lot of stuff.

 tracing-appender = "~0.2"
 tracing-core = "~0.1"
 tracing-subscriber = { version = "~0.3", features = ["local-time"] }

Is there an upgrade/migration documentation?

[nstinus]

Thank you @hawkw! Is it reasonable to expect this patch to be released under tracing-appender 0.2.x?

[hawkw]

Yup, we'll take care of backporting this and publishing a release at some point in the near future! Thanks for the contribution!