Question - Communicate metadata with message

[dsaingre]

Hi, I'm looking to implement a simple OpenTelemetry (OT) instrumentation to have distributed tracing between my actors (the goal is to find out where are the performances issues I have on another project using Thespian). I have several actors communicating with each other and basically, I want to trace the different messages exchange (ex: actor A received a message that took 2ms to process and then sent a message to actor B that took 1ms to process...).

The way OT works, I would need to propagate a context between the different actors, along with the messages exchanged (so OT can group the different calls together). I wanted to know if there were any way to send this context as a metadata along with the message I send between two actors.

A quick and dirty way to implement this would be to bundle the message with the context. The issue I have with this is that it impact all the application (as every actor now needs to separate the tracing context and the received message). That means that I need two implementations of my app if i want the tracing to be optional. That's why I thought that sending the context as a metadata would be "cleaner".

Does the current implementation of Thespian have anything like his? If not, would you consider it worth implementing for Thespian (I could try to implement it).

Thanks