Unit 1.20.0 release

[Valentin V. Bartenev]

Hi,

I'm glad to announce a new release of NGINX Unit.

It is yet another big release, featuring ASGI support for Python and a long list
of other improvements and bug fixes.

ASGI 3.0 is a modern standardized interface that enables writing natively
asynchronous web applications making use of the async/await feature available
inlatest versions of Python.  Now, Unit fully supports it along with WSGI.
Even more, Unit automatically detects the interface your Python app is using
(ASGI or WSGI); the configuration experience remains the same, though.  Also,
our take on ASGI relies on Unit's native high-perf capabilities to implement
WebSockets.

To learn more about the new feature, check out the documentation:

 - https://unit.nginx.org/configuration/#python

In addition, we've prepared for you a couple of howtos on configuring popular
ASGI-based frameworks with Unit:

 - Quart: https://unit.nginx.org/howto/quart/ (note a simple WebSocket app)

 - Starlette: https://unit.nginx.org/howto/starlette/

Finally, we've updated the Django howto to include the ASGI alternative:

 - https://unit.nginx.org/howto/django/


Changes with Unit 1.20.0                                         08 Oct 2020

    *) Change: the PHP module is now initialized before chrooting; this
       enables loading all extensions from the host system.

    *) Change: AVIF and APNG image formats added to the default MIME type
       list.

    *) Change: functional tests migrated to the pytest framework.

    *) Feature: the Python module now fully supports applications that use
       the ASGI 3.0 server interface.

    *) Feature: the Python module now has a built-in WebSocket server
       implementation for applications, compatible with the HTTP & WebSocket
       ASGI Message Format 2.1 specification.

    *) Feature: automatic mounting of an isolated "/tmp" file system into
       chrooted application environments.

    *) Feature: the $host variable contains a normalized "Host" request
       value.

    *) Feature: the "callable" option sets Python application callable
       names.

    *) Feature: compatibility with PHP 8 RC 1. Thanks to Remi Collet.

    *) Feature: the "automount" option in the "isolation" object allows to
       turn off the automatic mounting of language module dependencies.

    *) Bugfix: "pass"-ing requests to upstreams from a route was broken; the
       bug had appeared in 1.19.0. Thanks to 洪志道 (Hong Zhi Dao) for
       discovering and fixing it.

    *) Bugfix: the router process could crash during reconfiguration.

    *) Bugfix: a memory leak occurring in the router process; the bug had
       appeared in 1.18.0.

    *) Bugfix: the "!" (non-empty) pattern was matched incorrectly; the bug
       had appeared in 1.19.0.

    *) Bugfix: fixed building on platforms without sendfile() support,
       notably NetBSD; the bug had appeared in 1.16.0.


I would very much like to highlight one of these changes.  Perhaps the least
noticeable, it is still important for the entire project: our functional tests
moved to a more feature-rich pytest framework from the native Python unittest
module that we've used previously.  This change should enable us to write more
sophisticated tests, boosting the overall quality of our future releases.

All in all, this is a genuinely solid release, but I'm still more excited
about the things yet to come.  Yes, even more great features are coming our
way very shortly!  Right now, we are tinkering with route matching patterns
to support regular expressions; working on keepalive connection caching;
adding multithreading to application modules; and finally, fabricating the
metrics API!

We encourage you to follow our roadmap on GitHub, where your ideas and requests
are always more than welcome:

 - https://github.com/orgs/nginx/projects/1

Stay tuned!

  wbr, Valentin V. Bartenev