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

April 2, 2017

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

March 30, 2017

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

February 20, 2017

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)

November 8, 2016

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

September 19, 2016

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

September 13, 2016

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

September 3, 2016

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

A python notebook to experiment with the Apache Mesos HTTP API – Part 2 of 3

September 2, 2016

This is the second 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 This series is an extended (and updated) version of the talk I gave at MesosCon Europe 2015 updated for Apache Mesos 1.0.0, which has just been … More A python notebook to experiment with the Apache Mesos HTTP API – Part 2 of 3

A python notebook to experiment with the Apache Mesos HTTP API – Part 1 of 3

August 27, 2016

This is the first of a series of three articles that shows how to setup a Vagrant-based Apache Mesos test/development environment on your laptop; then how to run a Python notebook against the HTTP API; and finally, how to launch Docker containers on the running Agent VM. It is pretty jam-packed and requires a certain … More A python notebook to experiment with the Apache Mesos HTTP API – Part 1 of 3