[PureOS] SOURCE_DATE_EPOCH for PureOS ISO builds (was: "Re: Bits from PureOS")

[Chris Lamb]

Hi Jeremiah,

> > One remaining "policy" question here is what value we use for the
> > SOURCE_DATE_EPOCH environment variable
[…]
> I'm currently using debspawn but that wraps a container around Debian's
> live-build I believe. The build script recommended in the PureOS
> documentation requires cloning make-live, so perhaps the latest git
> commit can be used for source date epoch? Line 24 in the URL below;
> 
> https://source.puri.sm/pureos/infra/make-live/blob/master/auto/config

I fear you might be slightly misunderstanding this environment variable;
it shouldn't be hardcoded into some repo and nor should it depend on
whether we are using debspawn, etc. Rather, it should reflect the repo
or the "state of the world" itself.

Thus using the date from the HEAD commit of:

  https://source.puri.sm/pureos/infra/make-live

… seems to be a good start for now. We can always change it later, so
we need not spend many brain cycles beyond this on this topic.

> The question otherwise is where do I put SOURCE_DATE_EPOCH? I assume in
> some makefile as a variable. 

You should export it in your build script/cron that is doing the two
builds, or otherwise ensure that it is exported to the build process.
Everything "downstream" from there in the build process should not care
or really even know about it.

I believe:

   $ git --git-dir=/path/to/your/pureos/infra/make-live/.git log -1 --pretty=%ct

… will return the value we would use.

> > Huzzah! Indeed, this "Debian" thing you refer to sounds like they
> > have a bunch of good ideas. How can I find out more about it? ;)
> 
> It's complex. It's anarchic. You have to be technical. But it returns
> on your investment of time and energy a thousand fold - in bug reports.

Oh? Nah, I think I'll give it a miss…


Best wishes,

-- 
Chris Lamb
https://puri.sm