What do you need that https://github.com/luci/recipes-py/commit/f50a2af3c5190b5b9780855085bd5a8df0d4ec58 doesn't provide?

i see. Kitchen must pass that arg

the motivation for this was that milo can display initial property values.

however, this solution will work only if build has started. We must be able to display property values before build has started. I've filed  bug 693155 . I am not sure we need this bug.

The following revision refers to this bug:
  https://chromium.googlesource.com/infra/infra/+/9a24e51c4f5464c9b0d920a3b72492ea5d41c897

commit 9a24e51c4f5464c9b0d920a3b72492ea5d41c897
Author: Dan Jacques <dnj@chromium.org>
Date: Sat Feb 18 02:33:15 2017

Kitchen: recipe cleanup, LogDog initial properties

Have LogDog instruct the recipe engine, via operational arguments, to
emit initial properties. This will given Annotee access to the initial
properties, allowing the annotation stream to contain the complete set
of properties rather than just the properties that were changed during
recipe execution.

To enable this, it was useful to tear the recipe engine command generation
and execution logic out of "cook.py" into a dedicated "recipeRemoteRun"
type. This was halfway done before via a command generation function,
but now, since generation includes creation of operational arguments, it
is better to move it into a focused location.

Kitchen now creates a Kitchen-centric temporary directory to dump
operational arguments and properties JSON files to.

Switch several instances of error handling over to use annotated errors.

BUG= chromium:692266 
TEST=local
  - Ran locally.

Change-Id: Id727e1fe088bfe17680e2e0f98f57c49ea028e55
Reviewed-on: https://chromium-review.googlesource.com/444844
Reviewed-by: Nodir Turakulov <nodir@chromium.org>
Commit-Queue: Daniel Jacques <dnj@chromium.org>

[add] https://crrev.com/9a24e51c4f5464c9b0d920a3b72492ea5d41c897/go/src/infra/tools/kitchen/util.go
[add] https://crrev.com/9a24e51c4f5464c9b0d920a3b72492ea5d41c897/go/src/infra/tools/kitchen/proto/arguments.proto
[add] https://crrev.com/9a24e51c4f5464c9b0d920a3b72492ea5d41c897/go/src/infra/tools/kitchen/recipe.go
[modify] https://crrev.com/9a24e51c4f5464c9b0d920a3b72492ea5d41c897/go/src/infra/tools/kitchen/proto/package.pb.go
[modify] https://crrev.com/9a24e51c4f5464c9b0d920a3b72492ea5d41c897/go/src/infra/tools/kitchen/proto/README.md
[add] https://crrev.com/9a24e51c4f5464c9b0d920a3b72492ea5d41c897/go/src/infra/tools/kitchen/proto/arguments.pb.go
[modify] https://crrev.com/9a24e51c4f5464c9b0d920a3b72492ea5d41c897/go/src/infra/tools/kitchen/cook_logdog.go
[modify] https://crrev.com/9a24e51c4f5464c9b0d920a3b72492ea5d41c897/go/src/infra/tools/kitchen/cook.go
[modify] https://crrev.com/9a24e51c4f5464c9b0d920a3b72492ea5d41c897/go/src/infra/tools/kitchen/cook_logdog_test.go