[datastore] Implement __scatter__ special entity property.

It is useful when implementing datastore mappers, and for queries that want to
query for a random sample of the data.

See https://github.com/GoogleCloudPlatform/appengine-mapreduce/wiki/ScatterPropertyImplementation

R=iannucci@chromium.org

Change-Id: Ie954b123d632867ae2fe0833df51b117d078e06f
Reviewed-on: https://chromium-review.googlesource.com/1189742
Commit-Queue: Vadim Shtayura <vadimsh@chromium.org>
Reviewed-by: Robbie Iannucci <iannucci@chromium.org>
6 files changed
tree: 361a88b871b7d5cd4c659c510a5e1eb46508b654
  1. .travis.yml
  2. AUTHORS
  3. CONTRIBUTING.md
  4. CONTRIBUTORS
  5. LICENSE
  6. OWNERS
  7. PRESUBMIT.py
  8. README.md
  9. codereview.settings
  10. doc.go
  11. docs/
  12. example_test.go
  13. filter/
  14. impl/
  15. infra/
  16. pre-commit-go.yml
  17. service/
  18. tools/
README.md

gae: A Google AppEngine SDK wrapper

designed for testing and extensibility

THIS PACKAGE HAS NO API COMPATIBILITY GUARANTEES. USE UNPINNED AT YOUR OWN PERIL.

(but generally it should be pretty stableish).

GoDoc

Installing

LUCI Go GAE adaptor code is meant to be worked on from an Chromium infra.git checkout, which enforces packages versions and Go toolchain version. First get fetch via depot_tools.git then run:

fetch infra
cd infra/go
eval `./env.py`
cd src/go.chromium.org/gae

Contributing

Contributing uses the same flow as Chromium contributions.