LogDog: Use datastore config cache when available.

LogDog: Use datastore config cache when available.

Check if the datastore config cache is available. If it is, incorporate
it into the caching layer.

This will allow the microservices to leverage the project-local caching
for higher fault tolerance and less external reliance on hitting the
configuration service.

BUG=chromium:682465
TEST=None

Review-Url: https://codereview.chromium.org/2648433007
Committed: https://github.com/luci/luci-go/commit/9b5c2ac8e891eedde109b1c9ec77735d77a567ae

[dnj, 2017-01-20 23:40:17]

dnj@chromium.org changed reviewers:
+ iannucci@chromium.org

[dnj, 2017-01-20 23:40:17]

PTAL

[iannucci, 2017-01-21 00:32:24]

lgtm

https://codereview.chromium.org/2648433007/diff/20001/logdog/server/service/c...
File logdog/server/service/config/opts.go (right):

https://codereview.chromium.org/2648433007/diff/20001/logdog/server/service/c...
logdog/server/service/config/opts.go:51: // The cache is enable. Install it into
our backend.
enabled

https://codereview.chromium.org/2648433007/diff/20001/logdog/server/service/c...
logdog/server/service/config/opts.go:56: LockerFunc:      func(context.Context)
datastorecache.Locker { return locker },
I don't suppose it would make sense to have a LockerConst field to avoid the
closure here? probably not...

https://codereview.chromium.org/2648433007/diff/20001/logdog/server/service/c...
logdog/server/service/config/opts.go:63: log.WithError(err).Debugf(c, "Failed to
fetch datastore cache settings.")
Debug? Warning?

https://codereview.chromium.org/2648433007/diff/20001/logdog/server/service/s...
File logdog/server/service/service.go (right):

https://codereview.chromium.org/2648433007/diff/20001/logdog/server/service/s...
logdog/server/service/service.go:137: s.probeGCEEnvironment(c)
should this have been in the previous CL?

https://codereview.chromium.org/2648433007/diff/20001/logdog/server/service/s...
logdog/server/service/service.go:208: log.WithError(err).Debugf(c, "Failed to
create cloud datastore client.")
wdyt about reversing the severities? maybe debug for 'enabled' and warning for
'failed to create'? I assume it should be typical that we DO have datastore
access?

[dnj, 2017-01-21 02:00:02]

https://codereview.chromium.org/2648433007/diff/20001/logdog/server/service/c...
File logdog/server/service/config/opts.go (right):

https://codereview.chromium.org/2648433007/diff/20001/logdog/server/service/c...
logdog/server/service/config/opts.go:51: // The cache is enable. Install it into
our backend.
On 2017/01/21 00:32:23, iannucci wrote:
> enabled

Done.

https://codereview.chromium.org/2648433007/diff/20001/logdog/server/service/c...
logdog/server/service/config/opts.go:56: LockerFunc:      func(context.Context)
datastorecache.Locker { return locker },
On 2017/01/21 00:32:24, iannucci wrote:
> I don't suppose it would make sense to have a LockerConst field to avoid the
> closure here? probably not...

Acknowledged.

https://codereview.chromium.org/2648433007/diff/20001/logdog/server/service/c...
logdog/server/service/config/opts.go:63: log.WithError(err).Debugf(c, "Failed to
fetch datastore cache settings.")
On 2017/01/21 00:32:23, iannucci wrote:
> Debug? Warning?

Warning is fine.

https://codereview.chromium.org/2648433007/diff/20001/logdog/server/service/s...
File logdog/server/service/service.go (right):

https://codereview.chromium.org/2648433007/diff/20001/logdog/server/service/s...
logdog/server/service/service.go:137: s.probeGCEEnvironment(c)
On 2017/01/21 00:32:24, iannucci wrote:
> should this have been in the previous CL?

Ugh, looks like it was removed when I split. Oh well, it's here now.

https://codereview.chromium.org/2648433007/diff/20001/logdog/server/service/s...
logdog/server/service/service.go:208: log.WithError(err).Debugf(c, "Failed to
create cloud datastore client.")
On 2017/01/21 00:32:24, iannucci wrote:
> wdyt about reversing the severities? maybe debug for 'enabled' and warning for
> 'failed to create'? I assume it should be typical that we DO have datastore
> access?

Okay.

[dnj, 2017-01-21 02:00:07]

The CQ bit was checked by dnj@chromium.org

[dnj, 2017-01-21 02:00:07]

The patchset sent to the CQ was uploaded after l-g-t-m from
iannucci@chromium.org
Link to the patchset: https://codereview.chromium.org/2648433007/#ps40001
(title: "Comments.")

[commit-bot: I haz the power, 2017-01-21 02:00:17]

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, 2017-01-21 02:07:05]

CQ is committing da patch.

Bot data: {"patchset_id": 40001, "attempt_start_ts": 1484964007261970,
"parent_rev": "d3d6702a41f2ae2d2256d7e541917dbe20eccec8", "commit_rev":
"9b5c2ac8e891eedde109b1c9ec77735d77a567ae"}

[commit-bot: I haz the power, 2017-01-21 02:07:09]

Description was changed from

==========
LogDog: Use datastore config cache when available.

Check if the datastore config cache is available. If it is, incorporate
it into the caching layer.

This will allow the microservices to leverage the project-local caching
for higher fault tolerance and less external reliance on hitting the
configuration service.

BUG=chromium:682465
TEST=None
==========

to

==========
LogDog: Use datastore config cache when available.

Check if the datastore config cache is available. If it is, incorporate
it into the caching layer.

This will allow the microservices to leverage the project-local caching
for higher fault tolerance and less external reliance on hitting the
configuration service.

BUG=chromium:682465
TEST=None

Review-Url: https://codereview.chromium.org/2648433007
Committed:
https://github.com/luci/luci-go/commit/9b5c2ac8e891eedde109b1c9ec77735d77a567ae
==========

[commit-bot: I haz the power, 2017-01-21 02:07:10]

Committed patchset #3 (id:40001) as
https://github.com/luci/luci-go/commit/9b5c2ac8e891eedde109b1c9ec77735d77a567ae