Evergreen problem in sorting strings: How do you implement human-expected ordering when the strings have varying-length numbers in them? Prime example in the networking world is network interface naming in various devices. Example: >>> interfaces = [“1/1/1”, “1/1/2”, “1/1/10”, “1/1/11”, “1/1/10.32”, “1/1/10.311”, “1/1/10.312”, “eth-1/1/1.1”, “eth-1/1/1.2”, “eth-1/1/1.10”]>>> print(“\n”.join(sorted(interfaces)))1/1/11/1/101/1/10.3111/1/10.3121/1/10.321/1/111/1/2eth-1/1/1.1eth-1/1/1.10eth-1/1/1.2>>> That’s not ideal as the default string sorting […]
Category: Programming
Parametrizing Test Functions with Pytest
I will first create a class that is used for representing the Zabbix protocol flags (zabbix_flags.py): Subclassing enum.IntFlag is very suitable for this purpose, and enum.auto() can be used to represent the flag values. I have four test functions to check that the flag values work as expected (test_zabbix_flags.py): Let’s create a virtual environment and […]
Python Versions
Even though I’ve used Python programming language on-and-off since about year 2000, I only started paying more attention to specific Python versions around 2016 when I gradually started using Python more seriously in devops. When dealing with different runtime environments it is crucial to know which features are available in which Python versions. This page […]
Count Lines of Python Code
I have created a new application called lopc (Lines of Python Code). It is available for install with pip on PyPI (https://pypi.org/project/lopc/), and the source code is available on GitHub: https://github.com/markkuleinio/lopc The app really only counts the number of non-empty and non-comment lines of *.py files in the given directories. These are some features of […]
Python f-String Formatting Codes
Here is my short list about the common f-string formatting codes in Python: >>> score = 123.728 >>> f”{score}” ‘123.728’ Minimum field length: >>> f”{score:>10}” ‘ 123.728’ >>> f”{score:<10}” ‘123.728 ‘ >>> f”{score:^10}” ‘ 123.728 ‘ Number of decimals: >>> f”{score:.2f}” ‘123.73’ >>> f”{score:10.2f}” ‘ 123.73’ >>> f”{score:<10.2f}” ‘123.73 ‘ Padded with a character: >>> […]
Basics of Zabbix API with Python and PyZabbix
Zabbix API is the way to go when you need to manage Zabbix configurations or get data from Zabbix programmatically. For Python applications one of the community-based libraries is PyZabbix. Note: There is also a package called py-zabbix. That is a different one, not handled in this post. In this post I’ll show: How to […]
Configuring Logging in NetBox
Creating the log file and setting the permissions: $ sudo mkdir /var/log/netbox $ sudo touch /var/log/netbox/netbox.log $ sudo chown -R netbox.netbox /var/log/netbox $ Configuring NetBox (in /opt/netbox/netbox/netbox/configuration.py): You can set the level for the loggers as needed, in this setup the file handler accepts DEBUG and higher but the actual loggers (“django” and “netbox”) only […]
Basic Mocking with Pytest
Since I always seem to search for these examples over and over again, here it is, basic mocking with pytest. My example code is this (testmodule.py): It can be run: $ python3 testmodule.py In testfunc, sleeping $ Not surprisingly, running it takes about five seconds. The time.sleep() call simulates some long-running operation in the code. […]
Handling Retries in Python Requests
In my previous post we handled timeouts with requests. This post deals with making it easier to react to the errors using the built-in retry features. In this context let’s limit the retry-requiring cases in two categories: Cases that timed out (no response from the server) Cases that returned a transient error from the server […]
Handling Timeouts with Python Requests
The most usual way of making HTTP/HTTPS requests in Python applications is using the requests library. By default it doesn’t define any timeouts for the operations. It means that in specific circumstances a simple requests.get() call might not return at all. Depending on the nature of the application this is not desirable. This post demonstrates […]