TZJData

TZJData provides releases of the IANA tzdata compiled into the tzjfile (time zone julia file) format. The compiled data stored via package artifacts and used by the TimeZones.jl as an the source of pre-computed time zones.

The TZJData package uses semantic versioning like any other Julia package. Unlike most Julia packages however the TZJData package also uses build metadata to indicate the associated IANA tzdata release (e.g. TZJData release 1.0.0+2023c uses tzdata 2023c). Each TZJData release is only associated with a single IANA tzdata release but multiple TZJData releases may correspond to the same IANA tzdata release (i.e. 1.0.0+2023c and 1.0.1+2023c both use tzdata 2023c).

In addition to the standard semantic versioning rules used by Julia packages the TZJData package also adheres to the following internal rules:

1. The build metadata is used to indicate the tzdata version associated with each release (e.g. 2023c)
2. A minor release MUST be made when the tzdata version used has been updated to a newer version. A update to the tzdata version must be the immediate next release.
3. A major release MUST be made if the tzjfile format is changed in a non-backwards compatible manner
4. A major release MUST be used if it is desired to release older tzdata versions. In such a scenario ALL subsequent tzdata versions should be also be made into new releases to ensure the latest release in this major series is the latest tzdata.

The compiled tzjfile data is stored as a series of flat files in the same way zoneinfo is on Linux distributions. Users can read this data via the TimeZones.jl package:

julia> using TZJData

julia> using TimeZones: TZJFile

julia> function load(tzname)
           rel_path = joinpath(split(tzname, '/'))
           return open(TZJFile.read, joinpath(TZJData.ARTIFACT_DIR, rel_path), "r")(tzname)
       end
load (generic function with 1 method)

julia> load("Europe/Warsaw")
(tz"Europe/Warsaw", TimeZones.Class(:STANDARD))