Implement Async Schema Registry client (confluentinc#1965)

* Refactor for async support

* remove avro module import

* Add top level __all__ to refactored modules

* reduce diffs

* refactor

* formatting

* style fix

* fix flake8

* fix

* fix flake8

* revert

* reduce diff

* Implement async variants of SR clients and serdes

* refactor in prep for adding async

* Implement async variants of SR clients and serdes

* Refactor

* make functions async

* make schema id serializer changes to async

* fix

* add async changes and refactor into separate unasync script

* add check to source-package-verification

* fixes

* fix flake8

* ignore build

* fix tests

* fix

* fix flake8

* add async sr import

* Auto-generate README

* use timeout

* Refactor unasync and add tests to prove functionality

* fix

Author: rohitsanj

DEVELOPER.md

@@ -31,6 +31,15 @@ or:
 
 Documentation will be generated in  `build/sphinx/html`.
 
+## Unasync -- maintaining sync versions of async code
+
+    $ python tools/unasync.py
+
+    # Run the script with the --check flag to ensure the sync code is up to date
+    $ python tools/unasync.py --check
+
+If you make any changes to the async code (in `src/confluent_kafka/schema_registry/_async` and `tests/integration/schema_registry/_async`), you **must** run this script to generate the sync counter parts (in `src/confluent_kafka/schema_registry/_sync` and `tests/integration/schema_registry/_sync`). Otherwise, this script will be run in CI with the --check flag and fail the build.
+
 
 ## Tests
 

LICENSE

@@ -652,3 +652,36 @@ For the files wingetopt.c wingetopt.h downloaded from https://github.com/alex85k
  */
 
 
+
+LICENSE.unasync
+--------------------------------------------------------------
+For unasync code in setup.py, derived from
+https://github.com/encode/httpcore/blob/ae46dfbd4330eefaa9cd6ab1560dec18a1d0bcb8/scripts/unasync.py
+
+Copyright © 2020, [Encode OSS Ltd](https://www.encode.io/).
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+* Redistributions of source code must retain the above copyright notice, this
+  list of conditions and the following disclaimer.
+
+* Redistributions in binary form must reproduce the above copyright notice,
+  this list of conditions and the following disclaimer in the documentation
+  and/or other materials provided with the distribution.
+
+* Neither the name of the copyright holder nor the names of its
+  contributors may be used to endorse or promote products derived from
+  this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

pyproject.toml

@@ -73,3 +73,6 @@ optional-dependencies.all = { file = [
     "requirements/requirements-avro.txt",
     "requirements/requirements-json.txt",
     "requirements/requirements-protobuf.txt"] }
+
+[tool.pytest.ini_options]
+asyncio_mode = "auto"

requirements/requirements-tests.txt

@@ -9,3 +9,5 @@ requests-mock
 respx
 pytest_cov
 pluggy<1.6.0
+pytest-asyncio
+async-timeout

src/confluent_kafka/schema_registry/__init__.py

@@ -31,6 +31,7 @@
   RuleSet,
   Schema,
   SchemaRegistryClient,
+  AsyncSchemaRegistryClient,
   SchemaRegistryError,
   SchemaReference,
   ServerConfig
@@ -57,6 +58,7 @@
   "RuleSet",
   "Schema",
   "SchemaRegistryClient",
+  "AsyncSchemaRegistryClient",
   "SchemaRegistryError",
   "SchemaReference",
   "ServerConfig",