Use UTC timezone for ES indices

[pavolloffay]

Fixes #591

Signed-off-by: Pavol Loffay [email protected]

[coveralls]

Coverage remained the same at 100.0% when pulling ba16f14 on pavolloffay:fix-es-index-timezone into 1988a90 on jaegertracing:master.

[objectiser]

It might also be good if timezone can be overridden by config - with local as the default.

[pavolloffay]

I would prefer to do it in a separate PR. This just fixes inconsistency bug.

[pavolloffay]

I would even prefer no conf prop if it can be configured via the system

[yurishkuro]

it seems this change reverts another one specifically done to introduce the UTC, I think we have a conflict of requirements.

[pavolloffay]

Which one? https://github.com/jaegertracing/jaeger/pulls?q=is%3Apr+utc+is%3Aclosed are related to tests failures only, Probably inconsystency between local and UTC.

[vprithvi]

I strongly prefer UTC over local timezone because it's reliable when running components across regions, and doesn't have to deal with stuff like daylight saving time, etc.

What is the argument for updating to local tz?

Jaeger UI can translate these times to the user's current timezone.

[yurishkuro]

I also prefer UTC. Different instances of collectors must all agree on when the index names roll over, so leaving this up to local time zone on the host opens them up to errors due to misconfiguration or regional differences.

[pavolloffay]

It's a good argument when running in multiple regions. I think UTC is a better default, but it's harcoded. Setting to local leaves the opportunity to configure it in the system. However I don't know how people do it in practice.

I have updated to UTC.

[yurishkuro]

I remember at my previous job, which was a Java shop, we used to run all Java apps with an env variable setting the timezone to UTC, to avoid surprises of local timezones.

[yurishkuro]

something I don't understand. The issue said there is a discrepancy between reader and writer in the use of UTC, but this function is global. Is the function shared by the reader/writer? If not, I think that's the missed opportunity to remove the discrepancies.

I see that the reader has another function func indexWithDate(prefix string, date time.Time) string {.

So it looks like they both re-implement similar functionality instead of relying on a shared struct doing it for them.

[pavolloffay]

agree I will address it in a separate PR

[coveralls]

Coverage remained the same at 100.0% when pulling bb3f9bc on pavolloffay:fix-es-index-timezone into 362b0c1 on jaegertracing:master.