What does the Notification “badge” on MacOS System Preferences icon really mean?

If you have recently upgraded your MacOS laptop/desktop to 10.12.14, you will have noticed that now the System Preferences icon in the doc shows a mysterious “notification badge”: Just opening System Preferences shows absolutely no clue as to where the notification is coming from, nor what to do about it. It turns out that Apple … More What does the Notification “badge” on MacOS System Preferences icon really mean?

Using `notify-send` and `yagmail` to send an alert if /boot partition is about to run out of space

Sometimes, you need to send both a visual and email alert for something that is checked using a background process (for example, running a `crontab` job): `notify-send` and `yagmail` provide a more user-friendly alternative on Ubuntu Linux desktop than scraping logs. … More Using `notify-send` and `yagmail` to send an alert if /boot partition is about to run out of space

HOW-TO Generate an SSL Certificate with letsencrypt.com

There is a wealth of documentation about how to generated a Certificate using letsencrypt, the EFF free tool. However, if you are using g-suite to manage your main website or want an SSL certificate to do some testing during development, and may not have shell access to the WWW server (and, further, you are unable … More HOW-TO Generate an SSL Certificate with letsencrypt.com

A better mousetrap (or, how to improve on Java 8 Optional)

Overview The java.util.Optional class is a great addition in Java 8 as it enables a more expressive way of conveying the concept of a library API return value that may not be there. While it is not meant to replace the use of null values in code (and you will get warnings not to use … More A better mousetrap (or, how to improve on Java 8 Optional)

HOW-TO Publish a Pyton Package on PyPi

Create a setup.py file The arguments for setup() are documented here and are non-trivial: a good example is my filecrypt‘s setup.py file. NOTE Do not confuse setuptools with distutils – this is the correct import for setup.py: from setuptools import setup The trickiest part is figuring out the packages, modules and the script files: probably … More HOW-TO Publish a Pyton Package on PyPi

Docker for Mac and insecure registries

If you are using a private registry with a self-signed certificate, and need to connect to it from a macOS laptop, you are likely to incur in the following error: $ docker-compose up -d Pulling search (docker.registry.mydomain.io:5000/image:2.0.1)… ERROR: Get https://docker.registry.mydomain.io:5000/v1/_ping: x509: certificate signed by unknown authority it turns that (a) there is not much of … More Docker for Mac and insecure registries

A python notebook to experiment with the Apache Mesos HTTP API – Part 3 of 3

This is the third and final part of a three-part series: Part 1 describes the required setup and how to get Apache Mesos Master and Agent running in two Vagrant VMs; Part 2 shows how to connect to the HTTP API and accept resource offers. This series is an extended (and updated) version of the … More A python notebook to experiment with the Apache Mesos HTTP API – Part 3 of 3