I noticed the Go doc for context.Context includes the following snippet:

Do not store Contexts inside a struct type; instead, pass a Context
> explicitly to each function that needs it.

I think one potential reason for going against this advice is maintaining
context chain relationships in servers. In a server object, it seems
reasonable to provide a context when starting the server (which is valid
for the lifetime the server is serving) and the server to then store that
context in a struct. The reason it would be stored is that it could be used
to create child contexts when handling incoming data from the socket (or
whatever the server does).

The reason I would do this is two-fold:

   1. It is convenient and IMO elegant (particularly, but not exclusively,
   in test code) to be able to simply cancel a top-level context and have that
   respected throughout the chain, resulting in the server stopping and
   tearing itself down.
   2. It is a natural place for server-scoped contextual data. For example,
   we use a log library that allows log writer configuration to be stored in
   context. We could configure the log writer once for the server and have it
   then correctly applied to every action taken by the server, including
   request dispatches.

Does this seem like a reasonable approach, or are there other possibly
better practices for addressing these issues?

Obviously we must do things differently for HTTP and GRPC servers since
those libraries do not expose a way to provide a "parent context" for the
whole server. In those cases, we provide a method for registering HTTP
handlers that will wrap an incoming handler with one that decorates the
request context (for bullet #2 above; and we can use interceptors for
GRPC). For bullet #1, we have to implement our own cancellation propagation
-- like a goroutine that will stop the server(s) when the root context gets

I'm curious how others tackle these kinds of concerns.

*Josh Humphries*

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