Also perform minor cleanups on the ctxkey package itself.
Provide guidance on when to use ctxkey.Key[T] over ctxkey.New.
Also, allow for interface kinds because the value wrapping trick
also happens to fix edge cases with interfaces in Go.
Updates #cleanup
Signed-off-by: Joe Tsai <joetsai@digital-static.net>
The recent addition of RequestID was only populated if the
HTTP Request had returned an error. This meant that the underlying
handler has no access to this request id and any logs it may have
emitted were impossible to correlate to that request id. Therefore,
this PR adds a middleware to generate request ids and pass them
through the request context. The tsweb.StdHandler automatically
populates this request id if the middleware is being used. Finally,
inner handlers can use the context to retrieve that same request id
and use it so that all logs and events can be correlated.
Updates #2549
Signed-off-by: Marwan Sulaiman <marwan@tailscale.com>
