----- Mail original ----- > De: "Marcin Grzejszczak" <mgrzejszc...@vmware.com> > À: "core-libs-dev" <core-libs-dev@openjdk.java.net> > Envoyé: Vendredi 9 Avril 2021 16:29:32 > Objet: Instrumenting Executors - issues in Spring Cloud Sleuth and JDK16
> Hi! > > I'm the lead of Spring Cloud Sleuth [1], a project dedicated to working with > distributed tracing. We're propagating the tracing context e.g. through > threads. That means that when a user spawns a new thread we need to pass the > context from the old thread to the new one. Example - if the user uses an > Executor or an ExecutorService (e.g. via calling the execute(Runnable r) > method) then we need to wrap the Runnable in its trace representation. That > means that we retrieve the context from Thread A , pass it in the constructor > of the TraceRunnable and then restore it once the run method is called in > Thread B. > > The problem in Sleuth that we have with JDK16 is that we can't use reflection > to > ensure that we're wrapping all methods of any Executors [2]. In other words we > want to create a proxy around an existing Executor and wrap all methods. > Currently, we're using reflection cause Executor implementations such as > `ScheduledThreadPoolExecutor` have quite a few protected methods that we can't > access. What we would like to achieve is a delegation mechanism that we can > wrap all objects that the given Executor is using within their API (such as > Runnables, Callables, other Executors) in their trace representation and then > delegate calls for all methods to the wrapped object. That would also mean the > delegation to currently protected methods. > > If there's another way to achieve this other than opening the > java.util.concurrent API then I would very much like to use it. Currently with > JDK16 it's not possible to instrument that code so context propagation might > be > buggy when dealing with executors. I'm not sure if you are using an agent or not, if you are using an agent, you can redefine a module https://docs.oracle.com/en/java/javase/16/docs/api/java.instrument/java/lang/instrument/Instrumentation.html#redefineModule(java.lang.Module,java.util.Set,java.util.Map,java.util.Map,java.util.Set,java.util.Map) regards, Rémi > > Marcin Grzejszczak > Staff Engineer, Spring Cloud
