Use classic GAE for coordinator default frontend.

Use classic GAE for coordinator default frontend.

Now that AppEngine sockets API is default-integrated into gRPC calls, we
no longer need to run on a Managed VM in order to perform HTTP2
connections to BigTable. Since classic scales better (ATM), let's switch
to that.

BUG=None
TEST=dev
R=vadimsh@chromium.org

Review-Url: https://codereview.chromium.org/2591443002
Committed: https://github.com/luci/luci-go/commit/bde0f949595b702559b9c96be85a0d405ffad1f2

[dnj, 2016-12-19 16:14:53]

PTAL! Now that I am aware of the socket API, the last reason to use a Managed VM
is gone.

[Vadim Sh., 2016-12-19 20:24:36]

lgtm
I hope it works...

[dnj, 2016-12-20 02:46:45]

The CQ bit was checked by dnj@chromium.org

[commit-bot: I haz the power, 2016-12-20 02:46:48]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-12-20 02:48:37]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-12-20 02:48:38]

Try jobs failed on following builders:
  Luci-go Linux Precise 32 Tester on luci.infra.try (JOB_FAILED,
https://luci-milo.appspot.com/swarming/task/3332f17e07c4d210)
  Luci-go Linux Trusty 64 Tester on luci.infra.try (JOB_FAILED,
https://luci-milo.appspot.com/swarming/task/3332f17e257e4c10)
  Luci-go Mac Tester on luci.infra.try (JOB_FAILED,
https://luci-milo.appspot.com/swarming/task/3332f17e3f8b4f10)
  Luci-go Presubmit on luci.infra.try (JOB_FAILED,
https://luci-milo.appspot.com/swarming/task/3332f17d61e65810)

[dnj, 2016-12-20 03:10:27]

The CQ bit was checked by dnj@chromium.org

[dnj, 2016-12-20 03:10:27]

The patchset sent to the CQ was uploaded after l-g-t-m from vadimsh@chromium.org
Link to the patchset: https://codereview.chromium.org/2591443002/#ps20001
(title: "Rebase")

[commit-bot: I haz the power, 2016-12-20 03:10:30]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-12-20 03:15:46]

CQ is committing da patch.

Bot data: {"patchset_id": 20001, "attempt_start_ts": 1482203427341030,
"parent_rev": "66819f29dde260e3142b5b4f51efa5b4937f39e2", "commit_rev":
"bde0f949595b702559b9c96be85a0d405ffad1f2"}

[commit-bot: I haz the power, 2016-12-20 03:15:49]

Description was changed from

==========
Use classic GAE for coordinator default frontend.

Now that AppEngine sockets API is default-integrated into gRPC calls, we
no longer need to run on a Managed VM in order to perform HTTP2
connections to BigTable. Since classic scales better (ATM), let's switch
to that.

BUG=None
TEST=dev
R=vadimsh@chromium.org
==========

to

==========
Use classic GAE for coordinator default frontend.

Now that AppEngine sockets API is default-integrated into gRPC calls, we
no longer need to run on a Managed VM in order to perform HTTP2
connections to BigTable. Since classic scales better (ATM), let's switch
to that.

BUG=None
TEST=dev
R=vadimsh@chromium.org

Review-Url: https://codereview.chromium.org/2591443002
Committed:
https://github.com/luci/luci-go/commit/bde0f949595b702559b9c96be85a0d405ffad1f2
==========

[commit-bot: I haz the power, 2016-12-20 03:15:49]

Committed patchset #2 (id:20001) as
https://github.com/luci/luci-go/commit/bde0f949595b702559b9c96be85a0d405ffad1f2

[dnj, 2016-12-20 16:00:36]

A revert of this CL (patchset #2 id:20001) has been created in
https://codereview.chromium.org/2590263002/ by dnj@chromium.org.

The reason for reverting is: This works! But doing this through socket API is
measurably slower:

Logs for 6MB responses:
Classic: 12s, 12s

MVM: 1.9s, 2, 2, 2.1s.