Re: [Ntp] Finding leap-seconds.list

[Paul Eggert <[e-mail]>]

On 11/9/18 1:15 AM, Martin Burnicki wrote:
> Once I have a TZDIST server running, and a client that receives the
> data, how to use the received data?

The data will give you a series of transitions for a particular 
timezone, and these transitions can include the sort of leap-second info 
in leap-seconds.list. The transitions can be represented in multiple 
formats. The only format currently specified is iCalendar format (RFC 
5545), though it should be easy to add specs for other formats, such as 
the TZif binary format that tzcode uses to distribute leap-second data 
(see <https://tools.ietf.org/html/draft-murchison-tzdist-tzif-15>). I 
suppose it would be possible to shoehorn the leap-seconds.list text file 
format into TZDIST, e.g., by asking a TZDIST server for info about the 
UTC time zone in "leap-seconds.list" format.


> Can the TZDIST client update a local TZDB file on the fly?

It could, yes. In practice I don't know of anybody doing that in 
production. This stuff is reasonably bleeding-edge.


> If it can do this, can an application detect that the TZ rules may have
> been updated, and seamlessly start using the new rules, or has the
> application to be restarted to let the new TZ rules take effect?

Application seamlessness is outside the scope of TZDIST.

TZDIST does let a client ask a server "have the rules changed in any 
timezone?" efficiently, and this includes any changes to leap seconds. 
TZDIST doesn't provide any way for a server to push notifications of 
leap-second changes to clients, though.