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Randomly spacing cron jobs

By Jon Jensen
June 30, 2020

Cron is the default job scheduler for the Unix operating system family. It is old and well-used infrastructure — it was first released 45 years ago, in May 1975!

On Linux, macOS, and other Unix-like systems, you can see any cron jobs defined for your current user with:

crontab -l

If nothing is printed out, your user doesn’t have any cron jobs defined.

You can see the syntax for defining the recurring times that jobs should run with:

man 5 crontab

Important in that document is the explanation of the space-separated time and date fields:

field          allowed values
-----          --------------
minute         0-59
hour           0-23
day of month   1-31
month          1-12 (or names, see below)
day of week    0-7 (0 or 7 is Sunday, or use names)

A field may contain an asterisk (*), which always stands for "first-last".

For example, to make a job run every Monday at 3:33 am in the server’s defined time zone:

33 3 * * 1 /path/to/executable

Random interval scheduling

Sometimes it may be good to schedule a cron job to run at a somewhat random time: generally not truly random, but maybe at an arbitrary time within a specified time range rather than at a specific recurring …

Job opening: PHP / JavaScript developer

By Jon Jensen
June 29, 2020

This position has been filled. See our active job listings here.

We are looking for a PHP software engineer to work with us during business hours somewhere in the UTC-7 to UTC-4 time zones (U.S. Pacific to Eastern Time). This role can be full-time or part-time.

We are an Internet technology consulting company based in New York City, with 50 employees serving many clients ranging from small family businesses to large corporations. The company turns 25 years old this year!

Even before COVID-19 most of us worked remotely from home offices. We collaborate using SSH, GitHub, GitLab, chat, video conferencing, and of course email and phones.

What you will be doing:

• Develop new web applications and support existing ones for our clients
• Work together with End Point co-workers and our clients’ in-house staff
• Use your desktop OS of choice: Linux, macOS, Windows
• Use open source tools and contribute back as opportunity arises

What you bring:

Professional experience developing and supporting web applications in these technical areas:

• 5+ years of development with PHP and front-end JavaScript
• Frameworks such as Symfony, Laravel, Magento and Vue.js, React, Angular
• Databases such as PostgreSQL, MySQL, MongoDB, Redis, Solr, Elasticsearch, etc.
• Security …

Magento 2: Creating a custom theme

By Juan Pablo Ventoso
June 24, 2020

Photo by Maria Eklind, CC BY-SA 2.0

In my previous post, we went through the steps needed to create a custom module in Magento 2. While modules consist of a set of classes to add new features to Magento, a theme controls how these features, and the entire website in general, will be displayed to the user. As stated in the Magento guide, a theme uses a combination of custom templates, layouts, styles, and images to provide a consistent look and feel across a Magento store.

Creating a new Magento 2 theme

We can create a theme based on a default “parent” theme or create a standalone theme from scratch. In most cases, I would recommend the first option. For this example, we will use Luma as our parent theme. The other option would be inheriting from the default “blank” theme.

Here’s an initial task list to get our new theme ready:

• Create a new directory for the theme
• Create the registration.php script
• Create the theme.xml information file
• Activate the new theme

Creating a new directory for the theme

While all our backend code should go in app/code, the frontend content is expected to go in app/design. And as our theme will only apply design changes to the frontend content, we should …

Linux Development in Windows 10 with Docker and WSL 2

By Kevin Campusano
June 18, 2020

I’m first and foremost a Windows guy. But for a few years now, moving away from working mostly with .NET and into a plethora of open source technologies has given me the opportunity to change platforms and run a Linux-based system as my daily driver. Ubuntu, which I honestly love for work, has been serving me well by supporting my development workflow with languages like PHP, JavaScript and Ruby. And with the help of the excellent Visual Studio Code editor, I’ve never looked back. There’s always been an inclination in the back of my mind though, to take some time and give Windows another shot.

With the latest improvements coming to the Windows Subsystem for Linux with its second version, the new and exciting Windows Terminal, and Docker support for running containers inside WSL2, I think the time is now.

In this post, we’ll walk through the steps I took to set up a PHP development environment in Windows, running in a Ubuntu Docker container running on WSL 2, and VS Code. Let’s go.

Note: You have to be on the latest version of Windows 10 Pro (Version 2004) in order to install WSL 2 by the usual methods. If not, you’d need to be part of the Windows Insider Program to have access to …

Jamstack Conf Virtual 2020: Thoughts & Highlights

By Greg Davidson
June 16, 2020

Welcome to Jamstack Conf Virtual 2020

Last week I attended Jamstack Conf Virtual 2020. It had originally been slated to take place in London, UK but was later transformed into a virtual event in light of the COVID-19 pandemic. The conference began at 2pm London time (thankfully I double-checked this the night before!)—​6am for those of us in the Pacific Time Zone.

Up early for #jamstackconf 😎☕️ pic.twitter.com/ydjvrHWCZH

— Greg Davidson (@syncopated) May 27, 2020

Before getting too much further I wanted to mention that if you are not familiar with the Jamstack, You can read more about it at jamstack.org.

To virtually participate in the conference we used an app called Hopin. I had not heard of it before but was impressed with how well it worked. There were over 3000 attendees from 130+ countries one of the times I checked. Phil Hawksworth was the Host/​MC for the event and did a great job. There were virtual spaces for the stage, sessions, expo (vendors), and networking. If you opted to, the networking feature paired you with a random attendee for a video chat. I’m not sure what I expected going into it but I thought it was fun. I met a fellow developer from the Dominican …

Why upgrading software libraries is imperative

By Selvakumar Arumugam
June 10, 2020

Image by Tolu Olubode on Unsplash

Applications primarily run on front- and back-end programming languages, including library dependencies. Operating systems and programming languages can be periodically updated to run on the latest version, but what about the many libraries being used in the app’s front and backend? As we all know, it can be quite a daunting task to maintain and individually update a long list of software dependencies like the examples later in this post. Still, it is important to keep them updated.

This post dives into our experience upgrading a complex app with a full software stack and lots of dependencies. We’ll examine the benefits of upgrading, what you will need, and how to go about such an upgrade as simply as possible.

The app in question contained decade-old software and included extensive libraries when we received it from our client. The app used languages including Java, Scala, Kotlin, and JavaScript along with many libraries. The initial plan was to upgrade the complete software stack and libraries all at once due to the gap between versions. This proved to be more difficult than expected due to a host of deprecated and removed functionality as well …

Testing to defend against nginx add_header surprises

By Jon Jensen
May 29, 2020

These days when hosting websites it is common to configure the web server to send several HTTP response headers with every single request for security purposes.

For example, using the nginx web server we may add these directives to our http configuration scope to apply to everything served, or to specific server configuration scopes to apply only to particular websites we serve:

add_header Strict-Transport-Security max-age=2592000 always;
add_header X-Content-Type-Options    nosniff         always;

(See HTTP Strict Transport Security and X-Content-Type-Options at MDN for details about these two particular headers.)

The surprise (problem)

Once upon a time I ran into a case where nginx usually added the expected HTTP response headers, but later appeared to be inconsistent and sometimes did not. This is distressing!

Troubleshooting leads to the (re-)discovery that add_header directives are not always additive throughout the configuration as one would expect, and as every other server I can think of typically does.

If you define your add_header directives in the http block and then use an add_header directive in a server block, those from the http block will disappear.

If you define …

Implementing SummAE neural text summarization with a denoising auto-encoder

By Kamil Ciemniewski
May 28, 2020

If there’s any problem space in machine learning, with no shortage of (unlabelled) data to train on, it’s easily natural language processing (NLP).

In this article, I’d like to take on the challenge of taking a paper that came from Google Research in late 2019 and implementing it. It’s going to be a fun trip into the world of neural text summarization. We’re going to go through the basics, the coding, and then we’ll look at what the results actually are in the end.

The paper we’re going to implement here is: Peter J. Liu, Yu-An Chung, Jie Ren (2019) SummAE: Zero-Shot Abstractive Text Summarization using Length-Agnostic Auto-Encoders.

Here’s the paper’s abstract:

We propose an end-to-end neural model for zero-shot abstractive text summarization of paragraphs, and introduce a benchmark task, ROCSumm, based on ROCStories, a subset for which we collected human summaries. In this task, five-sentence stories (paragraphs) are summarized with one sentence, using human summaries only for evaluation. We show results for extractive and human baselines to demonstrate a large abstractive gap in performance. Our model, SummAE, consists of a denoising auto-encoder that embeds sentences and …