Unused method in ContextStorage

[bogdandrutu]

opentelemetry-java/api/context/src/main/java/io/opentelemetry/context/ContextStorage.java

Line 88 in eb4c4b8

static void addWrapper(Function<? super ContextStorage, ? extends ContextStorage> wrapper) {

I think this should be removed until concrete use-case available

[anuraaga]

This was added for two users I think, one JFR, and is demonstrated in the JFR test. It follows my experience in Armeria too where the SPI just too tedious for some trivial use cases.

[bogdandrutu]

Do you have a real example of a usage of the Armeria API?

[anuraaga]

Here's the original Armeria issue and PR line/armeria#2634 line/armeria#2723

Unfortunately can't find any OSS usages. /cc @minwoox @ikhoon @trustin

[trustin]

As far as I know, LINE corporation uses that feature internally. @minwoox or @ikhoon could give some concrete example.

[bogdandrutu]

@anuraaga I see, but it seems to have very limited usage. Can we postpone adding it until a real user asks us to do it.

[anuraaga]

@bogdandrutu @sfriberg @HaloFour Users asked for it, that's why we added it

[HaloFour]

I am actively using this API now so that I can determine when the current span changes so that I can update MDC and have the span information included in the logs.

I am using this in a Java Spring WebFlux application that is using the OpenTelemetry SDK as well as in a separate Scala tracing library that I've recently adopted to implementing the OpenTelemetry API interfaces and to use Context.

Here's some of where that Scala library relies on this API:

https://github.com/Comcast/money/blob/master/money-core/src/main/scala/com/comcast/money/core/Money.scala#L79
https://github.com/Comcast/money/blob/master/money-core/src/main/scala/com/comcast/money/core/context/MdcContextStorageFilter.scala

[minwoox]

Sorry for the late reply. 😅
At LINE corporation, there's a service that uses Tomcat and Armeria together. (The service was originally built using Tomcat and add Armeria server with a different port.)

They used to have their own logic for request scoping using thread-local. So they can log MDC parameters and retrieve some instances they store in the thread-local.
It used to work well until they decided to use asynchronous client and server with the Tomcat together.
They couldn't do the request scoping for the requests that are served from the asynchronous server.

So we decide to add the sort of hook so that they could solve the problem. 😄

[bogdandrutu]

Ok.. too late then 👍