[OE-core] [bitbake-devel] [RFC 8/9] hashserver: Add initial reference server

[Joshua Watt]

On Tue, 2018-07-17 at 13:11 +0100, Richard Purdie wrote:
> On Mon, 2018-07-16 at 15:37 -0500, Joshua Watt wrote:
> > Adds an initial reference implementation of the hash server.
> > 
> > NOTE: This is my first dive into HTTP & REST technologies. Feedback
> > is
> > appreciated. Also, I don't think it will be necessary for this
> > reference
> > implementation to live in bitbake, and it can be moved to it's own
> > independent project if necessary?
> > 
> > Also, this server has some concurrency issues that I haven't
> > tracked
> > down and will occasionally fail to record a new POST'd task with an
> > error indicating the database is locked. Based on some reading, I
> > believe this is because the server is using a sqlite backend, and
> > it
> > would go away with a more production worthy backend. Anyway, it is
> > good
> > enough for some preliminary testing.
> > 
> > Starting the server is simple and only requires pipenv to be
> > installed:
> > 
> >  $ pipenv shell
> >  $ ./app.py
> 
> I need to spend some time digesting this series but this patch did
> make
> me a little sad.
> 
> I'm hoping we can make the hash equivalence server something people
> use
> easily and perhaps part of bitbake. The dependencies you've used in
> this code mean it has a significantly higher "barrier to use" than
> most
> of our other code though :(
> 
> On the one hand I can understand people wanting to use dependencies
> and
> new technology. On the other, keeping things simple also has
> advantages.
> 
> Even the minimum python version is potentially problematic, we don't
> even have working recipes for python 3.6!
> 
> I appreciate its a reference and means we can test the rest of the
> code
>  so its good but we may need a different implementation of this
> ultimately.

I had a look around, and I think it should be quite feasible to
implement a reference server using only the standard Python libraries
(e.g. SimpleHTTPServer). The actual API that the server is *required*
to implement is very small (a single endpoint of "/v1/equivalent" with
GET and POST methods). It will probably have a number of limitations
(scalability, authentication, security, etc.) but for something to get
started or for automated testing purposes, I think it will be
sufficient.

I'll probably wait a few days at least before I loop back around to
look at that, so I'd like to leave this discussion open, e.g. Do we
want a simpler reference implementation?

> 
> Cheers,
> 
> Richard
>