This diff breaks the circular dependency between session and
tunnel, by introducing the concept of early session.
An early session is a session that is able to fetch the psiphon
configuration file _only_ if it's embedded in the binary.
This breaks `miniooni --tunnel=psiphon` for users who have
access to the OONI backend. They are not the users we are
writing this feature for, though, so I think this is reasonable.
At the same time, this opens up the possibility of creating
a psiphon tunnel when constructing a session, which is the
approach I was following in https://github.com/ooni/probe-cli/pull/286.
This work is part of https://github.com/ooni/probe/issues/985.
Once this diff is in, I can land https://github.com/ooni/probe-cli/pull/286.
We used to have an external package called libminiooni so that
third parties could use it. We wrote this such that we could
support github.com/bassosimone/aladdin.
That was actually a not-so-good idea because it added to the APIs
we needed to maintain.
Since the merge of engine into cli, such an API is not public
anymore and aladdin has been deprecated and archived.
Therefore, we can now cleanup the situation and merge libminiooni
into miniooni again, thus making the codebase more local.
This cleanup has been identified while working on
https://github.com/ooni/probe/issues/1299.
* refactor: miniooni should be outside of the engine
This is part of https://github.com/ooni/probe/issues/1335. We also need
to think whether we wanna keep libminiooni and miniooni separated.
The previous use case for having a top-level libminiooni was that of
enabling others to integrate miniooni into other binaries.
This was usegul when studying internet censorship in Spain in May 2020.
I am wondering whether we should be keeping this complexity. I am not
sure about this and probably we should be killing it.
(In any case, reducing complexity is not the objective of this diff,
since I would like instead to move things around with minimal changes
and make sure we have a ~good repository organization here.)
* fix: import in libminiooni
