Python SDK for Momento
Our minimum supported python version is currently 3.7. This is the oldest version of python that is
currently supported by the python maintainers as well:
https://en.wikipedia.org/wiki/History_of_Python#Table_of_versions
We rely on some features in asyncio that were introduced in 3.7. If we have a customer use case that
requires support for 3.6 then we can revisit at that time.
We use tox to run linting, tests, etc. Tox allows us to easily test against multiple versions of python as well as providing a simple way to organize build tasks (akin to a Makefile).
Our tox config is modeled on:
At the top of our tox.ini file, you will see a list of the
different python versions that we currently test against. For whichever
subset of these you wish to use locally, you will need to make sure that
you have a pyenv installation of that version. For example:
pyenv install 3.7.12
pyenv install 3.8.12
pyenv install 3.9.10
pyenv install 3.10.2
You need to run pyenv local ... once to configure this directory with
the list of pyenv python versions that you want tox to be able to use.
e.g.:
pyenv local 3.7.12 3.8.12 3.9.10 3.10.2
This will create a file called .python-version containing the desired
version numbers, and from now on whenever you cd into this directory,
pyenv and tox will automatically know which python versions you
want to use.
If you haven't installed tox yet:
pip install tox
If you want to test with all of the versions of python that we have listed
in our tox.ini, and you have already run pyenv local to register all
of the versions, run this command to do the initial setup of virtual envs
for all the python versions:
tox --notest
If you only intend to develop with one specific version of python, you can
do either of the following to limit tox to one version (in these examples,
python 3.9):
TOXENV=python3.9 tox --notest
or:
tox -e python3.9 --notest
The only trick to setting up your IDE is to point it to your preferred
virtualenv created by tox. These live in the .tox dir; e.g.
.tox/py39/bin/python.
Use Cmd + Shift + P to search for Python: Interpreter and select:
.tox/py39/bin/python
File->New Project->Python; when you get to the screen where it lets you
choose your python SDK, you may need to click Edit, then the + button
to register a new Python SDK, then choose the Existing radio button, then
navigate to e.g. .tox/py39/bin/python.
To test your changes in a python shell, just launch python from the desired tox virtualenv, e.g.:
.tox/py39/bin/python: this will start the interactive shell.
Alternately you may put all of your code in a my_test.py file and
run .tox/py39/bin/python my_test.py
We use mypy for ensuring that we have type annotations and that the types are correct.
(We should use it on all of our python projects; there is a movement
in the python community to try to create type stubs for all major open source libraries
via typeshed, similar to the DefinitelyTyped
project for javascript/typescript. In the not-too-distant future this will become table
stakes for open source python libraries.)
We use black for formatting and checking the formatting of the code.
To run the lint checks:
tox -e lint
To run the auto-formatter:
tox -e format
Integration tests require an auth token for testing. Set the env var TEST_AUTH_TOKEN to
provide it. The env TEST_CACHE_NAME is also required, but for now any string value works.
Example of running tests against all python versions:
TEST_AUTH_TOKEN=<auth token> TEST_CACHE_NAME=<cache name> tox
Example of running tests against one specific python version:
TOXENV=py39 TEST_AUTH_TOKEN=<auth token> TEST_CACHE_NAME=<cache name> tox
TODO (add black)
TODO (add mypy)