Re: [BuildStream] API proposal - enable iterating through all elements

[Tristan van Berkom <tristan van berkom codethink co uk>]

Hi,

On 2020-01-14 18:32, Thomas Coldrick via buildstream-list wrote:
> Hi,
>
> I'd just like to add my support to access to some sort of API that 
> allows third
> parties to load bst elements and play around with them properly. This 
> would have
> been useful in a few places really, not only this mirror/alias 
> checking. For
> another example, the issue asking for a `bst format`[0] would be much
> more suitable
> as an external tool using BuildStream API.
>
> I understand that allowing this would likely be a bit of an avalanche
> of making API
> public though, and we should be careful not to make everything public.
> Perhaps it
> would be possible to expose a set of high level wrappers of internal
> functions as
> some sort of "libbuildstream", allowing people access to loading etc. 
> to produce
> linters and project analysis tools?

Opening up a python library surface has been a possibility in the cards 
since the beginning indeed. With BuildStream 1.0 we tried to limit as 
much as possible which surfaces we would guarantee stability on, and we 
haven't opened the API up any further since then.

I would be tempted however to avoid such a change until ironing out the 
already limited API surfaces which are to land in bst 2 before opening 
up more API surfaces in master (and possibly doing some cleanup at that 
point ensuring we have a minimal API before sealing it up and stablizing 
it).

Cheers,
    -Tristan