Category: Side Coding

Blogging about side project coding tasks.

AWS Training

So over the Thanksgiving week, Udemy had a sale on video courses. Since my job search is going so slowly, I thought I’d maybe occupy the time by doing some of these courses, and I decided to start with the Amazon Web Services (AWS) certification training, starting with the AWS Certified Developer – Associate. Here are some impressions I’ve had after watching 10+ hours of course video:

  • The AWS offerings change so fast that it’s really easy for the course to fall behind reality. That might be one reason why they were selling the courses so cheap
  • AWS itself is very inconsistent in the way the UI for each individual web service is structured in the console. Some of them are very “here’s a list of options, pick one and configure it and launch it” and others are “here is a wizard to walk you through a bunch of steps that hopefully will lead to something you can launch”. It’s hard to describe exactly what I mean by that. That’s probably a result of how fast things are changing. Unfortunately, sometimes the course module was made when the console was the first way, but now it’s the second way and you basically have to watch half the video then try and remember everything he did on the first screen so you can do it on the Nth screen instead.
  • A couple of times, things in the AWS console have just failed. Sometimes it’s failed silently with no indication of why or even that it saw the “Create [blah]” button press. Other times it’s given very cryptic messages like “You have requested more instances (1) than your current instance limit of 0 allows”. (In that case, changing an obscure parameter from t2.small to t1.micro was the solution). The silent failure happened mostly in the Cloud Formation module when I was attempting to create a “Stack”, but after it appeared to fail silently (and nothing was shown in the list of stacks), and I tried to create it again, it complained that there was already a stack of that name and suddenly it’s there in the list of stacks again.
  • Other than the way the video is out of date in some place, my main complaint is that he is obviously reusing modules between the AWS Solutions Architect – Associate course and the AWS Developer – Associate course and so he’ll say “for this module, just use the S3 bucket named [blah] that you created in the last module” when you didn’t create anything of the sort. So then you have to hurriedly pause the video and create an S3 bucket and hope he didn’t expect any special permissions on it or any content in it.
  • A secondary complaint about that is that he never tells you when you’re done with a resource. I try to clean up all the S3 buckets and EC2 instance and whatever when it appears we’re done with them. I occasionally guess wrong. I wish at the end of a module he’d say “OK, we’re done with that bucket, feel free to delete it.” Sometimes he does, but mostly he doesn’t. I wonder if that’s an artifact of the fact that he’s mixing and matching modules? I’m probably over paranoid about leaving stuff around and getting charged for it, although when I started doing this course I discovered that a few years back I’d created an EC2 instance, stopped it, but never terminated it, so I guess their “free threshold” is high enough that I’m unlikely to hit it.

Give it a REST

As you might know, I’m currently looking for a job. And one thing you see in job ads is a requirement for experience with “REST APIs” or “RESTful services”. And as far as I can tell, it’s nothing more than a naming convention for your basic CRUD (Create, Read, Update, Delete) web services. If you write four URL handlers for the URLs “/item/create”, “/item/{item id}/read”, “/item/{item id}/update” and “/item/{item id}/delete” then you’re a filthy normie and unemployable, but if instead you make one URL handler for “/item/{item id}” and check the request type and do the read, update and delete based on the request type being “GET”, “PUT”, or “DELETE” respectively, (creation being done with a POST to the URL “/items”) then you’re a “RESTful” guru and will be showered in money.

Can we just agree that being a naming convention, it takes approximately 5 minutes to train somebody how to do this? And if my former employer would give me back my login for an hour or so I could go back and change all my AJAX calls to fit this naming convention and join the ranks of the REST API experienced.

Reimplementing Part 3

This is part 3 of my self-imposed project to reimplement the UI for an old website. You can read part 1 and part 2.

After some playing around with the “Step 2” interface, I realized that I really needed better error checking. I had error checking on the individual fields of the Geographic Panel, but no “overarching” check that all the fields were filled or all were unfilled. Plus I wanted the user to see the errors on the Geographic Panel even if you’ve closed the panel, and I also wanted to disable the “Start Generating” button until the errors are cleared. While I was at it, I added an error message if you don’t have any waypoint types selected. I’ve made those changes and pushed them to my GitHub project as the fourth commit and I’ve pushed it as a replacement to the previous mockup here.

I haven’t worked on this all week because of other calls on my time (work, job search, kayaking), so I haven’t made a start on the backend yet. But I’m thinking I’m going to be doing it in Python with Flask or Pyramid and SQLAlchemy. The original website is written in Perl, and frankly, I think the job market for Perl programmers is pretty rapidly shrinking and nobody is doing modern websites in Perl. But speed is of the essence, so that leaves Python or Java. The decision will probably come down to whichever of those two frameworks has better support for PostGIS.

Re-implementing Part 2

As described in my previous post, I gave myself a project to reimplement an old website using new technologies in order to prove to myself and to potential employers that I can do all the modern stuff.

The “Step 1” prototype was completed 15 days ago. I only wrote about it early today because I was debating with myself whether I should write up each step or do it all at the end. But during that time I’ve managed to get the static HTML page re-written as a React+Redux dynamic front end. I included the deficiencies I mentioned in the first post – the accordion panels open and close with a click anywhere on the title bar, and I’ve added “disclosure triangles” to make it more obvious that the title bars are meant to expand.

It doesn’t talk to a back end yet (it just simulates it using setTimeout), but it does so some nice interactive features

  • The title panes on each accordion panel update based on what you’ve chosen in the panel
  • It updates the countries, states and provinces in the “Country/State/Province” panel based on the latitude and longitude range you entered in the Geographic Area panel.
  • The state checkboxes don’t show up until you check the “US” checkbox in the country list, and similarly, the province checkboxes don’t show up until you check “CA” in the country list.
  • The “Start Generating” button is disabled unless you’ve selected at least one entry in the Airport Types, Navaid Types or Fixes in Charts panels.

Even taking into account the fact that I was learning as I went, I think the code looks ok. I tried to make some common base classes, but in many or most cases, I discovered that convolutions required to make it general weren’t worth it and I just ended up with similar but not identical code – case in point: the various “*Check” classes. I also ended up putting several classes for each accordion panel together in one file – I’m not sure if that’s considered best practices, but it seemed to make sense to me.

The mockup is here. This code is now the third commit on this project on GitHub.

So for a next step, I was planning to write a back end. The back end would have no actual HTML pages returned, just a bunch of AJAX calls and responses, mostly all returning JSON. So I was thinking Django, which is what I’ve been using for the last several years, would be too heavy for that. Similarly, the Java back ends I’m familiar with are also pretty heavy. On the other hand, the existing backend is written in Perl, and frankly, I don’t want to do anything in Perl anymore. I wonder if Flask and SQLAlchemy would be a good choice?

I’ll also have to figure out how to read and store cookies so we can store a session id just like the existing site does, but that’s probably not a big deal.

I also have to think of how the file generation will work. In the old code, I spawned off (fork/exec) a program to generate the file, and then had the web server process looking at the log file the generator task to see how far it had gotten. That made sense when the back end computer was busier and the generator task took 5-10 minutes – I didn’t want to tie up an Apache thread for that long, plus I could use a very primitive hand-rolled bit of Javascript to show progress. These days generating takes less than a minute, so I’m wondering if I couldn’t just do a return “Content-type: application/octet-stream” directly in the Apache thread. I’ll have to investigate.

A much more minor change I’m thinking of is in the country list putting the US and Canada at the top of the list instead of being strictly alphabetical because most of the users of the site are from the US or Canada and it would make it easier to find them.

Cosmetically, I reused the banner from the old site. It doesn’t really match the light and clean look of the rest of the site. I should probably make something more in keeping with the look I’m going for. Similarly, the favicon looks like a Palm Pilot which was fine when most people were using my data for Palm Pilots, but kind of wrong for GPX.

Someday, I’d like to add a simple map that can use to select the geographic area. Even better would be displaying or even picking countries, states, and provinces on the map. I’ve done some quick googling and I can’t find a good map library.

Also, if I could get the backend working fast enough, it would be cool to give a running count of how many waypoints the user is going to get in his file with the current parameters.

Update: See Step 3

Re-implementing an old web site in a modern style (Part 1)

So a few weeks ago I found out that my contract was going to be ending early due to a loss of funding. This is a great shame, not least because it gave me the opportunity to learn a bunch of new technologies, and also because I’ve really enjoyed working from home with minimal supervision. It’s been really helpful to my kayaking training to be able to go out and train during the afternoon and work in the evening after it gets too dark to paddle. It’s unfortunate timing because my contract ends at the end of April, and we’d already booked our cruise for two weeks towards the end of May.

But I’ve discovered a bunch of things since I’ve started looking for work:

  • Getting remote work is hard, even if you have 7 years of remote work.
  • Lots of potential employers want to see your work and your code, or worse, they want to see your GitHub profile. The problem with that is that most of my code is written for employers who don’t allow me to share the code I’ve written for them, and the websites I’ve worked on have been internal rather than facing the internet, so I can’t show them. Even worse, the only thing I’ve got on GitHub is a WordPress plugin that I forked for a project I did for the local kayak shop in exchange for a new boat. I used to contribute more to open source projects, but that was before the days of GitHub and mostly it involved emailed patch files. That was back in the days when I didn’t have so many hobbies and obligations.
  • While I’ve been doing a lot of JavaScript over the last 7 years, I haven’t used any of the cool frameworks. We’d actually made the decision to transition our project at my soon-to-be-ex job to Angular, but we never got around to it.
  • A whole bunch of companies are embracing coding exercises as an evaluation process. I don’t blame them – I’ve given interviews and I’ve received them, and they are an utterly shit way of evaluating people’s technical ability. But it is time-consuming if you have to do this for every company you apply to.

So I thought it would be useful if I could do a bit of a project that I could show to people, and put the code on GitHub, just like all the cool kids. And it should obviously use a JavaScript framework. And you’d think that I’d choose Angular, but there is a particular job here in Rochester that is currently top of my want list, and they use React, so I thought I’d use React.

So having made a decision on the front end technology, what I needed to do was pick a project. And the obvious candidate is my navaid.com website. While I keep the data updated loading FAA and Eurocontrol data every 56 days, I haven’t updated the UI in many years, and it shows. I’ve got several data generators there, but most of them are for Palm Pilot programs, so they’re probably not worth updating. But the GPX generator at http://navaid.com/GPX/ is still viable. So I’ll only reimplement that one.

The first step is to make a mockup of the new site. Actually, the first step was to watch a bunch of tutorial videos for React. Which start off teaching you about WebPack and ES6, and then React, and then React-Redux. I wasn’t 100% sure if I needed Redux, but it seemed like a good way to separate the data state code from the render code. But after watching the videos, it was time to write the mockup.

Obviously, since I have been using Bootstrap for the last several years, it would be easiest to make something modern and presentable using it. I just had to find a nice theme with a CDN. I settled on the “Paper” theme from Bootswatch, which has a nice simple clean look.

The obvious thing was to replace the multiple pages of the original GPX interface with a single page. The existing interface saves your last set of parameters in the database linked to a cookie and re-uses them next time you come back, and I’ve heard from users that they often just click through to the end and hit the action button without changing any of those parameters, so I thought it would be good to be able to display what they’ve loaded so they review to make sure that they don’t need to change anything and click the “Start Generating” button. So I decided on an accordion panel where the header for each type of filter shows what’s selected for that type and if you click on the header, you can modify it. Hard to describe, hopefully, easy to see in action.

So it took a few days, but the mockup is here. The code is the first commit on this project on GitHub.

After playing with it a bit, the first thing that leaps out at me is that the accordion panels should open when you click anywhere on the title bar, not just on the text. Also, Vicki suggested that the color of the accordion panel is a little blah and I should make it a nice light blue. You’ll see that in generation 2.

Update On thing I forgot to mention: While Bootstrap has support for responsive design, I made no attempt to make it work on mobile devices because generating and downloading large files isn’t something you’re likely to do on a phone or tablet. Probably the only change I’d have to make for mobile would be to use <div class=”row”> and <div class=”col-xs-12 col-md-4″> instead of tables, and possibly some tweaking of the padding or margin around checkboxes because they appear to overlap the label text a bit in Chrome and Safari on my iPad (although they don’t overlap in Chrome on my desktop when I choose “iPad mode”).

Also, as per a comment below, I’m also going to look at increasing the text size if I can do it without messing out up the look. The default font is 13px, which I’ve always thought was plenty big, but the Roboto font is a bit “thin”. I like it because it looks elegant, but maybe it doesn’t work at 13px? Bootswatch has some other clean themes, maybe I’ll have a look at some of them instead.

Update: You can read Part 2 and Part 3.