Deep dive into Pytest parametrization

Fixture parameters and pytest_generate_tests

Pytest is an amazing testing framework for Python. In this article I will focus on how fixture parametrization translates into test parametrization in Pytest.

ansible_default_ipv4 is not what you think

Most people think that ansible_default_ipv4 is some magical way to guess what IP address is the ‘main’ IP for a server.

It is not.

recovering Ceph from “Reduced data availability: 3 pgs inactive, 3 pgs incomplete”

When your pool stuck and you don’t know what to do.

How to filter a dictionary in Ansible

Let’s say you want to remove from your dictionary (object) all elements with value of empty string.

Input:

foo:
  key1: used
  key2: ""
  key3: another_used

How to test if __name__ == ‘__main__’

You need to test those two pesky lines at the end of your app, if you want 100% code coverage. For dynamically typed languages it is the absolute necessity to have 100% code coverage. Runtime type-checking will push all typos in names of functions and variables…

import_playbook with play-level condition

There is a very strange feature in Ansible. As far as I can see, it’s non-documented, but I found it extremely useful. (Scroll down to the…

Data manipulation in Ansible: json_query

The second big change in Ansible is an introduction of json_query filter in templates. It is big, because it allows to perform complicated queries without invoking slow Ansible loops. Whole data processing happens almost instantly, without cluttering output.

Using block for handlers in Ansible

Sometimes you want to run few operations for your handler instead of just one. In my case, a handler was designed to restart a main service, but with few conditions:

• This service may create a ‘lock file’ which says ‘do not restart me now’…

How to pass password to Ansible from environment variable

There is an idea that passing secrets via environment variables is more safe, than passing it via command line.

Ansible has few methods to accept password:

• Store it somewhere in…

Understanding Ansible’s check_mode

Recently I rediscovered one peculiar feature of Ansible I was aware of, but never used. It’s called check-mode.

Why I never used it? Because before 2.2 it was useless.