Fix for mysql2 error "Incorrect MySQL client library version! This gem was compiled for x.x.x but the client library is y.y.y."
This should be fixed in the latest LTS-branches of our mysql2 fork, 0.2.x-lts and 0.3.x-lts.
Use
gem 'mysql2', git: 'https://github.com/makandra/mysql2', branch: '0.2.x-lts' # for Rails 2.x
gem 'mysql2', git: 'https://github.com/makandra/mysql2', branch: '0.3.x-lts' # for Rails 3.x
in your Gemfile, and do a
bundle update mysql2
Background
mysql2 used to check that the client library used at runtime actually matches the one it was compiled against. However, at least on Ubunt...
Double loading issue with Ruby default gems
Ruby includes many standard gems that are bundled into the Ruby installation. Here is an example for the gem strscan
that will be displayed as default
:
gem list strscan
*** LOCAL GEMS ***
strscan (default: 3.0.1)
It is still possible to have newer version of a gem installed beside the default version:
gem install strscan
Fetching strscan-3.0.3.gem
Building native extensions. This could take a while...
Successfully installed strscan-3.0.3
1 gem installed
gem list strscan
*** LOC...
net-ssh and openssl-3.0.0
You'll need openssl-3 or newer for servers running 22.04
Ruby version 3.1
uses by default the gem openssl-3.0.0
. This can cause issues with the gem net-ssh (6.1.0
). This is a known bug.
Typically this can cause an error while deploying an application with capistrano:
could not verify server signature (SSHKit::Runner::ExecuteError)
or
Ed25519::VerifyError: signature verification failed!
As temporary workaround add the following line to your Gemfile
:
gem 'openssl', ...
Use DatabaseCleaner with multiple test databases
There is a way to use multiple databases in Rails.
You may have asked yourself how you're able to keep your test databases clean, if you're running multiple databases with full read and write access at the same time. This is especially useful when migrating old/existing databases into a new(er) one.
Your database.yml
may look like this:
default: &default
adapter: postgresql
encoding: unicode
username: <%= ENV['DATABASE_USER'] %>
host: <%= ENV['DATABASE...
Gem development: recommended gem metadata
The gemspec for gems allows to add metadata to your gem, some of which have a special meaning and are helpful for users.
You can provide links to your Github bugtracker or changelog file that are then used on the rubygems page of your gem (in the sidebar, e.g. see gem page of consul).
Here are some keys that should be filled:
Gem::Specification.new do |s|
s.name = 'my-gem'
s.homepage = 'https://github.com/makandra/my-gem'
s.metadata = {
'source_code_uri' => s.homepage,
'bug_tracker...
How to get information about a gem (via CLI or at runtime from Ruby)
When you need information about a gem (like version(s) or install path(s)), you can use the gem
binary from the command line, or the Gem
API inside a ruby process at runtime.
gem
binary (in a terminal)
You can get some information about a gem by running gem info <gem name>
in your terminal.
Example:
$ gem info irb
*** LOCAL GEMS ***
irb (1.4.1, 1.3.5)
Author: Keiju ISHITSUKA
Homepage: https://github.com/ruby/irb
Licenses: Ruby, BSD-2-Clause
Installed at (1.4.1): /home/arne/.rbenv/versions/3.0.3/lib/ruby/g...
Generating an Entity Relationship Diagram for your Rails application
This card explains how to generate an entity relationship diagram for your Rails application.
We also show how to limit your ERD to a subset of models, e.g. models inside a namespace.
Generating a full ERD
Option A: RubyMine
- Right-click anywhere in your project tree
- In the context menu, find the "Diagrams" menu item at/near the bottom
- Inside, choose "Show diagram" → "Rails Model Dependency Diagram"
- A new tab will open with the diagram inside. You can modify it there, and export it as an image.
Option B: Use rails-e...
Version 5 of the Ruby Redis gem removes Redis.current
Redis.current
will be removed without replacement in redis-rb
5.0.
Version 4.6.0 adds deprecation warnings for Redis.current
and Redis.current=
:
`Redis.current=` is deprecated and will be removed in 5.0.
If your application still uses Redis.current
, you can only fix it by no longer using it. Here is how.
Redis.new when you need it
You can easily instantiate a Redis
client when you need it.
There is probably already a constant like REDIS_URL
that you use to configure Sidekiq or similar. So just use that one.
``...
Integrating ESLint
Introduction
To ensure a consistent code style for JavaScript code, we use ESLint. The workflow is similar to integrating rubocop for Ruby code.
1. Adding the gem to an existing code base
You can add the following lines to your package.json
under devDependencies
:
"devDependencies": {
"eslint": "^8.7.0",
"eslint-config-standard": "^16.0.3",
"eslint-plugin-import": "^2.25.4",
"eslint-plugin-node"...
How to add esbuild to the rails asset pipeline
This are the steps I needed to do to add esbuild to an application that used the vanilla rails asset pipeline with sprockets before.
Preparations
- update Sprockets to version 4
- add a
.nvmrc
with your preferred node version (and install it) - add gems
jsbundling-rails
andforeman
to yourGemfile
:gem 'jsbundling-rails' group :development, :test do gem 'foreman' # ... end
bundle install
- run
bin/rails javascript:install:esbuild
in a console to prepare esbuild. - run
yarn install
...
Terminator setup for Procfile-based applications for more comfortable debugging
We use foreman
to start all necessary processes for an application, which are declared in a Procfile
. This is very convenient, but the outputs of all processes get merged together. Especially while debugging you might not want other processes to flood your screen with their log messages.
The following setup allows you to start Terminator in a split view with the Rails server running in the left pane and all remaining processes running via foreman in the right pane. It was heavily inspired by [this card](https://makandracards.com/makandr...
New gem: Rack::SteadyETag
Rack::SteadyETag
is a Rack middleware that generates the same default ETag
for responses that only differ in CSRF tokens or CSP nonces.
By default Rails uses Rack::ETag
to generate ETag
headers by hashing the response body. In theory this would enable caching for multiple requests to the same resourc...
Google Chrome now has a JavaScript bundle visualizer
Similar to the Webpack Bundle Analyzer, Chrome's new Lighthouse feature …
… shows a visualisation of your JavaScript bundles. It's compatible with sourcemaps and is great for understanding large JavaScript modules used by your page. It can also visualise unused bytes.
This is very helpful to visualize Javascript files in development. It also works on production code, where its usefulness depends on the structure of the productive Javascr...
ES6 imports are hoisted to the top
From Exploring ES6:
Module imports are hoisted (internally moved to the beginning of the current scope). Therefore, it doesn’t matter where you mention them in a module and the following code works without any problems:
foo(); import { foo } from 'my_module';
Footgun example
When you're not aware of import hoisting you may be surprised that your code runs in a different order than you see in the source file.
The example below is taken from the [...
RSpec: how to prevent the Rails debug page if you want to actually test for 404s
Within development and test environments, Rails is usually configured to show a detailed debug page instead of 404s. However, there might be some cases where you expect a 404 and want to test for it.
An example would be request-specs that check authorization rules. (If you use a gem like consul for managing authorization rules, you should always check these rules via power-specs. However, request-specs can be used as a light-weight version of integration tests here.)
In this case, Rails will replace the 404 page that you want to test ...
RSpec: automatic creation of VCR cassettes
This RailsCast demonstrated a very convenient method to activate VCR for a spec by simply tagging it with :vcr
.
For RSpec3 the code looks almost the same with a few minor changes. If you have the vcr
and webmock
gems installed, simply include:
# spec/support/vcr.rb
VCR.configure do |c|
c.cassette_library_dir = Rails.root.join("spec", "vcr")
c.hook_into :webmock
end
RSpec.configure do |c|
c.around(:each, :vcr) do |example|
name = example.metadata[:full_descripti...
Fix REPL of better_errors page
The gem better_errors offers a detailed error page with an interactive REPL for better debugging.
I had the issue that on a few projects with Ruby 2.5.8
, the REPL was not shown.
Solution
To make the REPL work properly with this Ruby version I had to update the gem binding_of_caller to at least version 0.8.0
.
From the [better_errors](https://github.com/BetterE...
RSpec matcher to compare two HTML fragments
The RSpec matcher tests if two HTML fragments are equivalent. Equivalency means:
- Whitespace is ignored
- Types of attribute quotes are irrelevant
- Attribute order is irrelevant
- Comments are ignored
You use it like this:
html = ...
expect(html).to match_html(<<~HTML)
<p>
Expected content
</p>
HTML
You may override options from CompareXML by passing keyword arguments after the HTML string:
html = ...
expect(html).to match_html(<<~HTML, ignore_text_nodes: true)
...
How to extract a Ruby gem
The rubygems binary gem
allows to extract a local gem with gem unpack GEMNAME
. For more details see the official documentation.
This was useful for compliance checks, when it was necessary to check the license of the C-files in nokogiri
.
Spreewald development steps
Our gem spreewald supports a few helpers for development. In case you notice errors in your Cucumber tests, you might want to use one of them to better understand the underlying background of the failure. The following content is also part of the spreewald's README, but is duplicated to this card to allow repeating.
Then console
Pauses test execution and opens an IRB shell with current cont...
How to avoid raising RestClient exceptions for 4xx or 5xx results
When using RestClient to make an HTTP request, it will raise an exception when receiving a non-successful response.
HTTP status codes like 422 or 403 might be totally expected when talking to APIs, so plastering your code with rescue RestClient::Exception
or similar can feel annoying.
It may not be intuitive, but the readme says you can also pass a block to methods like RestClient.get
or RestClient::Request.execute
. In that case, RestClient will not raise ...
GitHub Actions: Retrying a failing step
If you have a flaky command you can use the nick-invision/retry to re-try a failing command, optionally with a timeout:
---
...
jobs:
test:
...
steps:
- name: Run tests
uses: nick-invision/retry@v2
with:
timeout_seconds: 30
max_attempts: 3
command: bundle exec rake spec
How to checkout submodules in Gitlab CI
Accessing other repositories in Gitlab CI is not straight forward, since the access rights of the current pipeline might not be sufficient enough.
One approach is to use project access tokens and clone the repositories via HTTPS.
-
Create a project access token for all submodules you want to have access to with the setting
read_repository
- Add the secrets as environment variable to the main project you want to have access to submodules:
- Protected
false
...
- Protected
Upgrading Capybara with deprecated Integer selectors
Capybara added a deprecation warning in version 3.35.3 (version from 2019) that shows up if your selector is not of type String or Symbol.
Example:
click_link(10) # bad
click_link("10") # good
You might encounter this error e.g. in a pagination step or similar where you want to click on numbers. To figure out where this deprecation warning comes from try to run the tests with a step output.
bundle exec parallel_cucumber --test-options "--format=pretty" feature
The deprecation message looks like following:
Locator In...