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Ongoing observations by End Point people

Downtown San Diego Liquid Galaxy

Dave jenkins

By Dave Jenkins
July 27, 2020

San diego lg 1

We just installed a new Liquid Galaxy system for the Downtown San Diego Partnership in the conference room of their office in downtown San Diego (heh). As End Point continues to partner with public organizations, associations, and government agencies, the Liquid Galaxy is proving very effective for showing infrastructure projects, zoning districts, and, most importantly, public engagement with immersive data models. Downtown San Diego wanted to bring presentations and visualizations to a much larger canvas, and the Liquid Galaxy fit well with their open floor plan and large conference room.

Downtown San Diego is tasked with promoting the development of the downtown corridor to their members and the wider public. They can now build some great presentations to fully leverage the 7 large screens showing 3D models of new developments, zoning maps superimposed directly on Google Earth, and with the 4K videos all programmed to show in sequenced scenes, or simply fly through the city with a 6-axis controller and iPad.

This installation presented some unique challenges. The first was an asymmetric wall layout with a large flat wall, smaller angled wall, and an alcove that needed accommodation. The first thing we did was to go onsite and take some measurements. We also received a 2D floorplan from our client. From this floorplan we built a 3D model using Blender:

Blender model

One more blender model

This allowed us to propose some options for screen layouts in the room, with either an asymmetric screen pattern to match the wall closely, or a symmetric/​balanced pattern that would show better but come out from the wall further. The client chose the symmetric layout (of course), which then drove the second challenge: how to build out a mounting frame in a pandemic?

Our engineers put down their keyboards and picked up their circular saws. Dan Briones, an accomplished carpenter as well as our Director of Operations, designed a full mounting frame in his shop in New York, which was all completely flat-packed...


liquid-galaxy

Job opening: Windows Systems Integrator

Jon jensen

By Jon Jensen
July 23, 2020

New York City East River & FDR Drive

We are looking for a Windows systems integrator in the New York City metropolitan region to work with us.

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

This is a consulting position, so excellent verbal and written communication, troubleshooting, and time management skills are required, along with a good sense for when to quickly escalate issues to resolve them efficiently as needed.

Skills and tools

You will need to have extensive experience in the Microsoft Windows ecosystem: the MS Windows OS, Windows networking, Active Directory management via Group Policies, MS Exchange Server, MS SQL Server, etc.

The greater knowledge of and larger base of experience you have with these, the better:

  • Remote management & monitoring (RMM) systems, such as ConnectWise Manage and Automate
  • Mobile devices and mobile device management (MDM) systems, such as SOTI MobiControl, AirWatch, and MaaS360
  • VMware’s vSphere or Microsoft Hyper-V hypervisors
  • Managing firewall security policies, switches, and wireless access points (WAPs)
  • Storage management, connecting via iSCSI and SMB3 SAN & NAS devices
  • Managing cloud services and migrating to and from such services as Office 365, Azure, Amazon Web Services, and Google Cloud Platform
  • An understanding of disk imaging, backup, and recovery strategies
  • Scripting or development experience, such as PowerShell, .NET/C#, etc.

Tell us about your other skills and strengths. We’ll be interested to hear about them.

Location

This position requires (at least once COVID-19 subsides) some work in our Manhattan office along with some on-site work at customer locations in the NYC metro region. Working remotely is also possible from time to time.

Benefits

  • Flexible, sane work hours
  • Annual bonus opportunity
  • Paid holidays and vacation
  • Health insurance subsidy
  • 401(k) retirement savings plan

company jobs windows

Deploying (Minecraft) Servers Automatically with Terraform

Zed jensen

By Zed Jensen
July 16, 2020

Banner

Last year I bought an old Dell Optiplex on eBay to use as a dedicated Minecraft server for my friends and me. It worked well for a while, but when my university switched to online classes and I moved home, I left it at my college apartment and was unable to fix it (or retrieve our world save) when it failed for some reason. I still wanted to play Minecraft with friends, though, so I had to figure out a solution in the meantime.

I’d previously used a basic DigitalOcean droplet as a Minecraft server, but that had suffered with lag issues, especially with more than two or three people logged in. Their $5 tier of virtual machine provides 1GB of RAM and 1 CPU core, so it shouldn’t be too much of a surprise that it struggled with a Minecraft server. However, more performant virtual machines cost a lot more, and I wanted to keep my solution as cheap as possible.

I mentioned this to a co-worker and he pointed out that most companies don’t actually charge for virtual machines on a monthly basis; in reality, it’s an hourly rate based on when your virtual machine instance actually exists. So, he suggested I create a virtual machine and start my Minecraft server every time I wanted to play, then shut it down and delete it when I was finished, thus saving the cost of running it when it wasn’t being used.

Of course, you could do this manually in your provider’s dev console, but who wants to manually download dependencies, copy your world over, and set up a new server every time you want to play Minecraft? Not me! Instead, I used Terraform, an open-source tool that lets you describe your desired infrastructure and then sets it up for you.

In this post, I’ll show how I got my server setup streamlined into one Terraform configuration file that creates a virtual machine, runs a setup script on it, copies my Minecraft world to it with rsync, starts the Minecraft server, and adds a DNS entry for your new server.

Picking a provider

As I mentioned earlier, I’ve used DigitalOcean...


automation terraform cloud

Random Strings and Integers That Actually Aren’t

Josh williams

By Josh Williams
July 2, 2020

Rowntree’s Randoms sweets

Image from Flickr user fsse8info

Recently the topic of generating random-looking coupon codes and other strings came up on internal chat. My go-to for something like that is always this solution based on Feistel networks, which I didn’t think was terribly obscure. But I was surprised when nobody else seemed to recognize it, so maybe it is. In any case here’s a little illustration of the thing in action.

Feistel networks are the mathematical basis of the ciphers behind DES and other encryption algorithms. I won’t go into details (because that would suggest I fully understand it, and there are bits where I’m hazy) but ultimately it’s a somewhat simple and very fast mechanism that’s fairly effective for our uses here.

For string generation we have two parts. For the first part we take an integer, say the sequentially generated id primary key field in the database, and run it through a function that turns it into some other random-looking integer. Our implementation of the function has an interesting property: If you take that random-looking integer and run it back through the same function, we get the original integer back out. In other words…

cipher(cipher(n)) == n

…for any integer value of n. That one-to-one mapping essentially guarantees that the random-looking output is actually unique across the integer space. In other words, we can be sure there will be no collisions once we get to the string-making part.

The original function is based off the code on the PostgreSQL wiki with just a few alterations for clarity, and should work for any modern (or archaic) version of Postgres.

CREATE OR REPLACE FUNCTION public.feistel_crypt(value integer)
  RETURNS integer
  LANGUAGE plpgsql
  IMMUTABLE STRICT
AS $function$
DECLARE
    key numeric;
    l1 int;
    l2 int;
    r1 int;
    r2 int;
    i int:=0;
BEGIN
    l1:= (VALUE >> 16) & 65535;
    r1:= VALUE & 65535;
    WHILE i < 3 LOOP
        -- key can be any function that returns numeric between 0 and 1
       ...

postgres python tips

Randomly spacing cron jobs

Jon jensen

By Jon Jensen
June 30, 2020

bird footprints in snow

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 interval.

This can be useful to keep simultaneous cron jobs for different users from causing predictable spikes in resource usage, or to run at a time other than the start of a new minute, since cron’s interval resolution doesn’t go smaller than one minute.

There isn’t any simple built-in way to randomize the scheduling in classic cron, but there are several ways to get it done:

cronie RANDOM_DELAY

The version of cron included with Red Hat Enterprise Linux (RHEL), CentOS, and Fedora Linux is cronie. It allows us to set the variable RANDOM_DELAY for this purpose. From its manual:

The RANDOM_DELAY variable allows delaying job startups by random amount of minutes with upper limit specified by the variable. The random scaling factor is determined during the cron daemon startup so...


sysadmin automation

Improving max() performance in PostgreSQL: GROUP BY vs. CTE

David christensen

By David Christensen
June 30, 2020

Spice Baazar Photo by Maxpax, used under CC BY-SA 2.0, cropped from original.

When working with large tables, even simple actions can have high costs to complete. What queries are acceptable for smaller tables can often be less than ideal when applied to large tables, so your specific choice of approach to a given problem becomes more important.

Note: We are using PostgreSQL 12, which supports some nice features like parallel btree index building, which can speed up parts of this process compared to earlier versions. We are using the default settings for this, which lets PostgreSQL use up to 2 parallel backend workers to speed up some operations.

Say you have a table table_a with multiple grouping fields field_a and field_b and you want to find the maximum value of another field field_c for each group.

The direct approach is to do something like the following:

SELECT field_a, field_b, max(field_c) FROM table_a GROUP BY 1,2;

This is functional and very straightforward. However, even if you have an index on (field_a, field_b, field_c), this can end up taking quite a long time if the tables are large. Let’s look at an actual example and the numbers we use.

First, let’s create our table:

CREATE TABLE table_a (field_a varchar, field_b integer, field_c date);

And populate it with some data:

INSERT INTO table_a
SELECT field_a, field_b, now()::date + (random() * 100)::int AS field_c
FROM unnest(array['AAA','BBB','CCC','DDD','EEE','FFF']) field_a,
    generate_series(1, 10000) field_b,
    generate_series(1, 1000);

This statement will populate this table with 60 million rows, consisting of 1000 random dates per each field_a, field_b pair; our task will now be to see how to efficiently find the max value for field_c for each grouping.

Let’s now create an index on all 3 fields:

CREATE INDEX ON table_a (field_a, field_b, field_c);

For the purposes of sanity/​clarity when testing approaches, let’s VACUUM and ANALYZE that table:

VACUUM ANALYZE table_a;

And let’s check...


postgres database

Job opening: PHP / JavaScript developer

Jon jensen

By Jon Jensen
June 29, 2020

waterfall and mountains

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 consciousness
  • Git version control
  • Automated testing
  • HTTP, REST APIs
  • Bonus for familiarity with another ecosystem such as Ruby on Rails, Python/​Django, Java, .NET/​C#, Node.js, Go, Rust, Scala, Kotlin, Swift …

These work traits are just as important:

  • Strong verbal and written communication skills
  • An eye for detail
  • Tenacity in solving problems
  • A feeling of ownership of your projects
  • Work both independently and as part of a team
  • Focus on customer needs
  • A good remote work environment

What work here offers:

  • Collaborate with knowledgeable, friendly, helpful, and diligent co-workers around the world
  • Flexible, sane work hours
  • Annual bonus opportunity
  • Freedom from being tied to an office location
  • For full-time staff: paid holidays and vacation
  • For U.S. employees: health insurance subsidy...

company jobs php remote-work

Magento 2: Creating a custom theme

Juan pablo ventoso

By Juan Pablo Ventoso
June 24, 2020

blue and yellow paint from a tube on a canvas 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 create the new directory for it under the path app/design/frontend. If we want to create a theme for the admin area instead, we need to create the directory inside app/design/adminhtml.

Let’s create a directory named EndPoint (our vendor name, continuing with the example from our previous article) and a subdirectory inside it, MyTheme:

cd {website_root}
mkdir -p app/design/frontend/EndPoint/MyTheme

Creating registration.php

Similar to the file we created for our module, registration.php tells Magento to register the new theme with the name and location we specify. Our file will be located at app/design/frontend/EndPoint/MyTheme/registration.php and should have the following content:

<?php
\Magento\Framework\Component\ComponentRegistrar::register(
    \Magento\Framework\Component...

magento php ecommerce
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