Postgres: alpine variant missing /usr/share/zoneinfo

[ptman]

LOG:  could not open directory "/usr/share/zoneinfo": No such file or directory

which results in:

SELECT * FROM pg_timezone_names;
ERROR:  could not open directory "/usr/share/zoneinfo": No such file or directory

which can be fixed with

apk add tzdata

[ptman]

https://github.com/docker-library/postgres/pull/221

[tianon]

This was actually excluded intentionally (https://github.com/docker-library/postgres/blob/03f4064a045114f56fa445eb602339faaf79eeec/Dockerfile-alpine.template#L101-L102):

# tzdata loading functionality is optional, and fails gracefully
#       tzdata \

Once it's added, it cannot be removed again (for users who don't need it), and it does add ~1.288 MB to the image size.

Something like the following should work to add it after the fact (which will then be imported during docker-entrypoint.sh and available at runtime):

FROM postgres:9.6-alpine

RUN apk add --no-cache tzdata

[ptman]

Thanks for the explanation.

[lockie]

For anyone interested: there's an unofficial repo of postgres in alpine with tzdata enabled out of the box.

[tianon]

Is the timezone data used commonly enough that we should reconsider including it by default?

Another really simple solution would be to mount in zoneinfo from the host, ie -v /usr/share/zoneinfo:/usr/share/zoneinfo:ro

[lockie]

Is the timezone data used commonly enough

It sorta is. The Django documentation suggests that timezone should be set for Postgre for performance reasons.

[ptman]

It seems to add 1.288 MB to the image

[lockie]

@ptman it is around 1/50 of image size, which is not that terribly much.

[tianon]

Yeah, seems sane enough -- someone want to make a PR uncommenting the existing line and removing the comment it has? (probably adding a new one pointing to that Django documentation as a real-world example)