Using your ruby-webmock configuration for your local test service

An article, posted 5 months ago filed in , , , , , , , & .

I recently shared an overview article about Stubbing External Services in Rails. I found it when looking for the best way to stub a pletora of services in a microservices environment. Sure, docker (or whatever) everything and run it locally / in your test suite. But unless you've plenty of disk- and memory space, this isn't always a viable option. The alternative: simulate the service. Mock or stub the endpoint.

VCR and Webmock

The go to gems are Webmock, which catches request and allows you to define the responses explicitly and VCR, which allows you to record responses, and play back.

VCR is quite cool, but as it is a recorder of earlier responses, there may be a lot of noise to dig trough when trying to make the responses a bit more generic (dealing with random token requests and what else)

For testing I pers…

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Global variables in Rails

An article, posted 7 months ago filed in , , & .

A quick note, because I was using the wrong search terms. If you want to share e.g. the current user of an app with a model you can now (since Rails 5.2) use a model inheriting from ActiveSupport::CurrentAttributes. Before you were required to pass this current user explicitly or find another way to access state.

Note that this can either be a good thing or a bad thing (tl;dr: thread-local global state makes apps unpredictable)

And even the docs warn against abusing this feature. Powerful tools can come with dangerous consequences :) Global variables are immensely powerful. Use with care. I'm not even sure if I'm going down this path…

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Revisiting taming ruby's memory bloat meta-edition

An article, posted 7 months ago filed in , , , , & .

There are a lot of things that I don't understand. One of these things is how memory management really works. Memory management is hard, and even though I use languages that do garbage collecting by themselves, long running ruby apps seem to run out of memory after n number of days. Even the pro’s find it quite hard. While I previously resetted the failing app every now and then, I was triggered by Mike Perham’s (creator of Sidekiq) post: “Taming Rails memory bloat”.

When you start searching for the memory bloat problem, you'll find several directions. The easiest is changing a global variable which changes the number of “arena’s” where memory allocation takes place (note: I’m in no position to explain all this, please follow the references). The fanciest, however, seems to be changing the memory allocator from glibc's default 'malloc' to jemalloc. See for example [this](https://www.speedshop.co/2017/12/04/malloc…

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Prometheus for slow stats

An article, posted 8 months ago filed in , , , , , , , & .

Prometheus is a statistics collecting tool that originated from SoundCloud. Designed to be used in high performance environments, it is build to be blazingly fast. Hence, the client typically is expected to be blazingly fast as well, gathering and presenting data within nanoseconds. For Ruby on Rails applications however this has lead to an unresolved issue with the Prometheus ruby-client when the same application is forked (typical for Puma, Passenger and other popular ruby-servers). The Prometheus client collects data within its own fork before serving it to the exporter endpoint. This can or cannot be a problem. When you measuring response times, running averages from a random fork may be good enough. However, when you're also counting data over time you're having separate counters in …

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Be a (unit-testing) minimalist

An article, posted 12 months ago filed in , , , & .

Still (2013) a great talk by Sandy Metz on testing, and how to do it right, without getting too theoretical. While this talk is on ruby, and it uses a Rails framework for testing, it really is applicable to any other language (only the syntax will probably be a wee bit shittier ;))

Watch Rails Conf 2013 The Magic Tricks of Testing by Sandi Metz on YouTube

(and while unit-testing is between brackets, in general, being a minimalist when writing code really is a good idea)

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Tag descriptor

Rails CMS-systems

An article, posted about one year ago filed in , & .

When developing full stack webapplications, I typically use Rails. While Rails is the perfect system to create CMS'es, for sites that are less applications and more websites CMS-gems for Rails may help.

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JavaScript & Rails: a `webpacker` evaluation

An article, posted more than one year ago filed in , , , , , , , & .

Webpacker is still opt-in for new Rails projects. But this might change. The JavaScript ecosystem is moving fast and new JavaScript frameworks are pushing customer’s expectations to higher levels. To use these frameworks with your Rails app, you had a few options:

  • Include the JavaScript manually; which requires you to manually copy the files in place
  • Use a gem-wrapper to to install the JavaScript library; but this required quite some maintenance on the Gem-author’s side.
  • Try to mangle npm or yarn into the asset pipeline yourself
  • Use Rails Assets (an automagic Gem-wrapper)

A small praise for Rails Assets

I have been using rails-assets.org the past few years to keep my JavaScript dependencies up to date. It thought it was smart solution; instead of requiring individual developers to maintain Gem-wrappers, Gem wrappers are created on the fly by RailsAssets.org. It was smart and light weight on the developers side and worked perfectly with the Rails' Asset p…

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Niet hier uitgevonden

An article, posted about 2 years ago filed in , , , , , , & .

Op m’n verzoek om vooral met vragen te komen in mijn kortgeleden begonnen mailinglijst hierbij een antwoord op een lezersvraag:

> “Ben ook wel benieuwd waarom je gekozen hebt voor het hosten van een eigen mailinglist vs de beschikbare saas oplossingen als mailchimp e.d.”

Het bouwen van je eigen mailing-systeem heeft trekken van het “Not invented here”-syndroom. En ja: ik had deze mailing heel erg gemakkelijk met iets als MailChimp kunnen sturen. MailChimp zou bij de omvang van deze mailinglist gratis zijn, leuke statistieken geven, een grafische editor geven en waarschijnlijk was m'n fout waarin iedereen bij de eerste verzending ‘Rick’ werd genoemd niet voorgekomen. "Niet hier uitgevonden" is dus een hele domme reden om iets niet te gebruiken, maar waarom dan toch eigen mailinglist-tool maken?

Foto door [Kelly Sikkema](https://unsplash.com/photos/r077pfFsdaU?utm_source=unsplash&utm_medium=referral&utm_content=creditC…

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Tag descriptor

murb ♥︎ ruby

An article, posted about 2 years ago filed in & .

It may not be the fastest programming language, nor is it the most popular language when it comes to the numbers game, but how can you not fall in love with:

 10.times { print "Hello!" }

(instead of something like for(var i=0; i<10; i++){ console.log("Hello!"); })

Do things with sets like:

["a", "b", "c"] & ["b", "c", "d"] ## gives you ["b", "c"]
[1,2,3] + [4,5] ## gives you [1,2,3,4,5]
["a", "b", "c"] - ["b", "c", "d"] ## gives you ["a"]

Or (with a little (opinions differ on this one ;)) help of Rails):

10.days.ago

That offers you exactly what you would think it would return: the date of 10 days ago.

And no ;'s, only brackets when absolutely needed, everything is an object…

Yes, it's actually a language a human might understand, and still: it is pretty powerful, powering some of the most popular sites on the web, like AirBnB, Shopify, Basecamp (they're the creators of Ruby on Rails), Github, Kickstarter, Twitch, Strava and man…

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Unit-testing your front-end code in a Rails project: Yarn, Tape & Rails

An article, posted about 2 years ago filed in , , , , , , & .

I like Rails, but one thing that Rails falls short in is Javascript dependency management.

While Rails Assets, a proxy that allows for listing Bower packages in your Gemfile makes managing front-end libraries good enough for most front-end work, RailsAssets itself is mainly addressing asset management; it doesn’t allow for integrated management of additional development tools and binaries, useful for e.g. JavaScript-testing (besides the fact that Bower is kind of considered to be deprecated these days).

There are different ways of bundling Javascript, but since Rails 5.1, yarn is the defacto choice for Rails.

Installing Yarn

You can install yarn either trough npm npm install -g yarn, or if you’re on a mac, using homebrew: brew install yarn. I chose the latter.

To prepare your rails project run rails yarn:install.

Add tape for testing JavaScript & Coffeescript

There are [different testing fram…

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Phoenix’ Channels

An article, posted almost 3 years ago filed in , , , , , , , , , , & .

I started exploring Phoenix for one thing only: Channels (or actually fast real time communication over websockets). In this post I explore how to use them (yes this is a follow up of My first Phoenix-app-post).

Preparing for the authentication problem

Websockets don’t pass session cookies. Because we don't have access to these we need to transfer the user's identity in a different way. One of the recommendations I found was passing a user_token using a ``-tag (adjusting templates/layout/app.html.eex):

We can access this with a simple query selector in javascript:

document.querySelector("meta[name=user_token]").content

But that’s for later. Let’s move to the server side, since we need something to connect to, a Socket.

Socket

In our default project there is alrea…

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My first Phoenix app

An article, posted almost 3 years ago filed in , , , , , , , , & .

Some time ago I actually initiated my very first Phoenix app, but was a bit disappointed by the lack of a rich box of gems (like that of ruby's) and/or I didn't have the time to invest heavily in researching all the possibilities. One of my new year resolution was to actively pursue more knowledge, hence I'm giving it a second shot.

Why Phoenix?

I'm a full-stack Rails developer, but I needed real time messaging. That is not something Rails is typically good at (although it works), but Elixir (with its Erlang base) is well known for, even in the ruby community. Phoenix wraps Elixir in a nice Rails-like package ready for web and API development.

Requirements

  • Authentication
  • Broadcasting filtered messages based on tags
  • Writing messages

Preparation

  1. Install Elixir (macOS & homebrew: brew install elixir) and make sure you have [node.js](https://nodejs.or…

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ActionCable and authentication with Devise (2/2)

An article, posted about 3 years ago filed in , , , , , , & .

This is a short follow up on the previous article in which the ActionCable basics were explained. We can now add some level of authentication. Authentication is a bit harder than simply registering some before_action’s, but it is perfectly doable, especially if you've survived the previous tutorial.

From the official Action Cable guide we can simply reuse the full connection.rb template:

module ApplicationCable
  class Connection < ActionCable::Connection::Base
    identified_by :current_user
 
    def connect
      self.current_user = find_verified_user
    end
 
    protected
      def find_verified_user
        if current_user = User.find_by(id: cookies.signed[:user_id])
          current_...

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Getting started with Rails ActionCable (1/2)

An article, posted about 3 years ago filed in , , , , , , & .

As the lead developer at HeerlijkZoeken.nl I wanted to try the new Rails ActionCable technology for a new feature: shopping lists. The idea is that you can walk in a store or on a market, mark an ingredient as checked when you add it to your (physical) basket and continue shopping. ActionCable can make the experience nicer because it, based on WebSockets, allows for real time notifying other viewers and editors of the same shopping list. No more shouting around in the supermarket: I’ve got the milk! Sure, nothing essential, but I needed an excuse ;)

(Note that we recently migrated from Rails 4, so not everything was in place in our app, just ignore the bits Rails already made for you; everything has been tested with Rails 5.0.0.1)

Getting the basics right

To start: You need a web server that can open multiple threads, so if you’re still using Webrick in development (which can’t rece…

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SocialLinker

An article, posted more than 3 years ago filed in , , , , , , , , , , & .

I had a few projects that I thought could use some share 'buttons', but I didn't like to include the JavaScript loaded and privacy invading share buttons that the networks try to sell you by default. Neither did I like to concatenate the links with all variables required for each project… so I wrote a small rubygem on a back and forth train trip (#ilovetrains ;)): social_linker.

The idea is that you share something about a certain subject, hence you initalize the SocialLinker::Subject and then you'll be able to generate share links from it:

subject.share_link(:facebook)

How it works

Initialize the subject with enough material to generate links from, such as the page's url, maybe the media url (mainly for Pinterest type-shares), a description, tags etc.

For example, initialize the SocialLinker::Subject as follows:

social_linker_subject = SocialLinker::Subject...

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