Ability to set the base context

[cyx]

I'm not sure there's a facility for this already, but after searching through the code and docs, there doesn't seem to be a way to do it without making a middleware.

Basically the usecase is like:

ctx := context.WithValue(context.Background(), "foo", "bar")

mux := chi.NewMux()
mux.SetContext(ctx) // or could be in the constructor, or a functional option thing?

In any case the underlying goal is to just easily set the base context. Let me know if this makes sense.

[pkieltyka]

@cyx yea I've gone back and forth with this one myself. I've implemented it, then removed it, then thought perhaps we should bring it back.

can you describe your use case for a base context? what would you use it for?

[VojtechVitek]

I was thinking about custom context types:

ctx := &MyCustomAppContext{} // implements context.Context interface
router := chi.NewRouter(ctx)

func Handler(w http.ResponseWriter, r *http.Request) {
  ctx := r.Context().(*MyCustomAppContext)

  // I can use custom methods/helpers defined on the *MyCustomAppContext type now..
  // this means... saving a lot of boiler plate and type conversions 
  sessionUser := ctx.SessionUser()

  session := ctx.Session() // instead of session, ok := ctx.Value("session").(*Session)

  db := ctx.DBSession() // DB connection assigned from a middleware?

  w.Write([]byte("yay"))
}

[cyx]

For our usecase, the most important part is cancellation.

        ctx, cancel := context.WithCancel(context.Background())

        graceful.AddSignal(syscall.SIGTERM)
        graceful.PostHook(cancel)

        // more code here that adds on to context.

FWIW we were originally using github.com/guregu/kami. We definitely love a working PR we have moving to chi, and this is the only piece that felt weird to me TBH.

[pkieltyka]

@cyx that isn't actually a reliable solution to a graceful shutdown of your servers. A cancelation signal will cancel all in-process goroutines. What is actually necessary is a signal on the context that tells the listeners to stop any further processing, but to finish up their work. See #58

[pkieltyka]

@cyx let me know if you get any success or some other ideas on how to approach it though

[cyx]

@pkieltyka do you sit in any irc / slack channel? Would be interested to talk about this in detail.

[pkieltyka]

@cyx id love to get into it, but I'm under a pile of work onboarding a bunch of customers this week

[pkieltyka]

btw, here is a PR to add this functionality #92

I'll be adding a _examples/graceful example too to this PR that uses the new https://github.com/goware/valve package to manage graceful shutdowns, utilizing a base context

[pkieltyka]

done in a526d0c