Re: [BuildStream] Migration of plugins away from BuildStream core

[Jim MacArthur <jim macarthur codethink co uk>]

On 26/02/2019 12:09, Laurence Urhegyi wrote:
> On 2019-02-26 11:43, Jim MacArthur via BuildStream-list wrote:
> > On 26/02/2019 11:07, Phil Dawson via BuildStream-list wrote:
> > > From various discussions on the mailing list and during the last two
> > > gatherings, this part seems to be fairly uncontroversial. However,
> > > please shout out if you disagree.
> > Could you link to the start of some of the discussions? I have done a
> > search for 'migration', 'plugins' and 'bst-external' on the mailing
> > list archive, and can't find anything other than a discussion on the
> > docker plugin.
>
> I rounded up some of the chats we had at the October 2018 gathering in 
> this mail:
>
> https://mail.gnome.org/archives/buildstream-list/2018-December/msg00145.html 
>
>
> But it may actually be better to start with the January Gathering 
> notes on the topic:
>
> https://docs.google.com/document/d/1bENn0gIHDPyTXaRwqSoA2F11gn55vvWLB7qMIe3Pk1U/edit#heading=h.hh1no92d8o4r 
>
>
> And some previous posts from Phil on migrating OSTree and testing 
> BuildStream against external plugins:
>
> https://mail.gnome.org/archives/buildstream-list/2019-January/msg00056.html 
>
> https://mail.gnome.org/archives/buildstream-list/2019-February/msg00005.html 
I've now read all the above sources, and all the documents linked from 
your first message, but not anything linked further than that; this has 
taken me about 30 minutes so far.

Nothing yet in there says why we're planning to move plugins out of 
core. The only one that hints at it is Agustin's summary of the 2018 
Gathering, which quotes:

"BuildStream doesn't want to keep all that baggage"

... and that's it, that's all the justification I can find. Note that 
this document also says:

"Second reason is for keeping plugins that are not yet mature enough 
[...] but eventually want to move into the BuildStream core, e.g. 
X86Image". This directly contradicts today's plan; we are planning to 
move mature plugins out of core.

Also: "BuildStream cannot maintain every plug-in that people write, we 
cannot bring them all into core. But we should have a convenient set of 
plugins distributed with the core"... which I fully agree with. It then 
explains some of the pain users have already reported from having to use 
bst-external.

Incidentally I've spent most of today trying to get bst-external 
installed inside a docker container so I can use the quilt plugin. It's 
a long way from what Phil Dawson describes as "trivially installable".

I agree with what Mathieu Bridon has said: Without things like git and 
tar, BuildStream does not do anything useful.

Jim