ezic
ezic is a set of erlang utilities for the Olsen timezone database files. See the tz database page for more information.
API
ezic:localtime(TimeZone) -> datetime()ezic:utc_to_time(universal_datetime(), TimeZone) -> local_datetime()ezic:utc_from_time(local_datetime(), TimeZone) -> universal_datetime()ezic:zone_convert(from_datetime(), TimeZoneFrom, TimeZoneTo) -> to_datetime()
Admin API
ezic:load("/path/to/tzdata") -> ok
Setup
# download the timezone data files
wget 'ftp://elsie.nci.nih.gov/pub/tzdata*.tar.gz'
tar -xvzf tzdata*.tar.gz -C /path/to/tzdata
# remove a few troublesome files
cd /path/to/tzdata
rm *.sh *.tab factory
# build and run ezic
make all run
1> ezic:load("/path/to/tzdata").
2> ezic:localtime("Australia/Adelaide").
Purpose
The recommended way of handling timezones in erlang involves setting the system environment variable TZ to the desired timezone, then calling erlang time functions. This technique has a few key issues:
- it only works on *nix systems,
- it depends on your system's timezone data (preventing custom timezone hackery), and
- you can create race conditions if you aren't careful
A self-containted erlang solution would avoid these pitfalls, but to be fair, it introduces a few others:
- you (the admin) are responsible for updating the timezone database yourself
- ezic has not yet been battle tested
I think both of these issues will disappear over time, so I opted to write ezic.
License
This project is in the public domain.