slog: add context arguments

Implement a more direct way to pass a context to a Handler.

- Add {Info,Debug,Warn,Error}Ctx functions and methods, that take a context.

- Add an initial context argument to Log and LogAttrs.

- Remove Logger.WithContext, Logger.Context and the Record.Context
  field: the output functions will pass their context argument
  directly to the Handler.

This CL also includes a somewhat unrelated set of changes:

- Add the Record.Add(...any) method, which behaves like Record.AddAttrs
  but processes its arguments like Logger.Log.

- Remove LogDepth and LogAttrsDepth, since they can now be implemented
  with exported API.

A later CL will update the package documentation.

Change-Id: I9216615598e1582a28fd48d78e85ff019d223924
Reviewed-on: https://go-review.googlesource.com/c/exp/+/469856
Run-TryBot: Jonathan Amsterdam <jba@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Alan Donovan <adonovan@google.com>
8 files changed
tree: 1485dd7054398ca1dae17959b1cc7d65343e3f6e
  1. apidiff/
  2. cmd/
  3. constraints/
  4. devtools/
  5. ebnf/
  6. ebnflint/
  7. errors/
  8. event/
  9. inotify/
  10. io/
  11. jsonrpc2/
  12. maps/
  13. mmap/
  14. rand/
  15. shiny/
  16. shootout/
  17. slices/
  18. slog/
  19. sumdb/
  20. typeparams/
  21. utf8string/
  22. .gitattributes
  23. .gitignore
  24. codereview.cfg
  25. CONTRIBUTING.md
  26. go.mod
  27. go.sum
  28. LICENSE
  29. PATENTS
  30. README.md
README.md

exp

PkgGoDev

This subrepository holds experimental and deprecated (in the old directory) packages.

The idea for this subrepository originated as the pkg/exp directory of the main repository, but its presence there made it unavailable to users of the binary downloads of the Go installation. The subrepository has therefore been created to make it possible to go get these packages.

Warning: Packages here are experimental and unreliable. Some may one day be promoted to the main repository or other subrepository, or they may be modified arbitrarily or even disappear altogether.

In short, code in this subrepository is not subject to the Go 1 compatibility promise. (No subrepo is, but the promise is even more likely to be violated by go.exp than the others.)

Caveat emptor.