Category: Coding

Gossip-based Failure Detectors – 0.8.0 released

September 8, 2017

We have just released version 0.8.0 of our distlib C++ library that implements a number of popular distributed systems algorithms. This concludes a first iteration of the “SWIM Gossip Protocol” for failure detection: the implementation is now fully thread-safe and can scale up to many servers with minimal process overhead. The gossip_example.cpp toy server shows how a client … More Gossip-based Failure Detectors – 0.8.0 released

File Encryption (and Decryption) Made Easy

August 30, 2017

A new release of the Crytto library (0.4.0) has just been published, which greatly simplifies encrypting (and decrypting) files The new release adds the decrypt script which, when combined with the existing automatic retrieval of the encryption key from the keystore, makes it a breeze to decrypt files. For example, if you had encrypted your … More File Encryption (and Decryption) Made Easy

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