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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 […]
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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.
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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 […]
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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 […]
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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 […]
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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 […]
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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 […]
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A python notebook to experiment with the Apache Mesos HTTP API – Part 2 of 3
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 […]
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A python notebook to experiment with the Apache Mesos HTTP API – Part 1 of 3
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 […]
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Python Magic Methods
Make your code more pythonic by using magic methods in your classes.
Code Trips & Tips
Adventures in developing distributed systems in Go, Java , Python and C++
Code Trips & Tips 