check-patroni/CONTRIBUTING.md

Contributing to check_patroni

Thanks for your interest in contributing to check_patroni.

Clone Git Repository

Installation from the git repository:

$ git clone https://github.com/dalibo/check_patroni.git
$ cd check_patroni

Change the branch if necessary.

Create Python Virtual Environment

You need a dedicated environment, install dependencies and then check_patroni from the repo:

$ python3 -m venv .venv
$ . .venv/bin/activate
(.venv) $ pip3 install .[test]
(.venv) $ pip3 install -r requirements-dev.txt
(.venv) $ check_patroni

To quit this env and destroy it:

$ deactivate
$ rm -r .venv

Development Environment

A vagrant file is available to create a icinga / opm / grafana stack and install check_patroni. You can then add a server to the supervision and watch the graphs in grafana. It's in the vagrant directory.

A vagrant file can be found in this repository to generate a patroni/etcd setup.

The README.md can be generated with ./docs/make_readme.sh.

Executing Tests

Crafting repeatable tests using a live Patroni cluster can be intricate. To simplify the development process, interactions with Patroni's API are substituted with a mock function that yields an HTTP return code and a JSON object outlining the cluster's status. The JSON files containing this information are housed in the ./tests/json directory.

An important consideration is that there is a potential drawback: if the JSON data is incorrect or if modifications have been made to Patroni without corresponding updates to the tests documented here, the tests might still pass erroneously.

The tests are executed automatically for each PR using the ci (see .github/workflow/lint.yml and .github/workflow/tests.yml).

Running the tests manually:

• Using patroni's nominal replica state of streaming (since v3.0.4):

  pytest ./tests
  

• Using patroni's nominal replica state of running (before v3.0.4):

  pytest --use-old-replica-state ./tests
  

• Using tox:

  tox -e lint    # mypy + flake8 + black + isort ° codespell
  tox            # pytests and "lint" tests for all supported version of python
  tox -e py      # pytests and "lint" tests for the default version of python
  

Please note that when dealing with any service that checks the state of a node in patroni's cluster endpoint, the corresponding JSON test file must be added in ./tests/tools.py.

A bash script, check_patroni.sh, is provided to facilitate testing all services on a Patroni endpoint (./vagrant/check_patroni.sh). It requires one parameter: the endpoint URL that will be used as the argument for the -e/--endpoints option of check_patroni. This script essentially compiles a list of service calls and executes them sequentially in a bash script. It creates a state file in the directory from which you run the script.

Here's an example usage:

./vagrant/check_patroni.sh http://10.20.30.51:8008