Test Post

Alex

QA
Automation

Handle environment variables on a heroku app from CLI

The heroku config commands of the Heroku CLI makes it easy to manage your app’s config vars.

cd myapp

# This will list all the env variables from your app
heroku config 

# Set env you want to add/update
heroku config:set S3_KEY=12345

# Get specific env
heroku config:get S3_KEY

# Removes specific env
heroku config:unset S3_KEY

CSS Container Queries

I've always seen responsive elements styled with CSS media queries. These often need more media queries to make them look good on different page sections. There's a way to skip the headache.

Use of container queries to apply CSS styles with the element's container size in mind instead of the viewport size:

/* Create a container context */
.container {
  container-type: inline-size;
}

/* Default font size */
.card h2 {
  font-size: 1em;
}

/* Updated font size when the container is larger than 500px */
@container (min-width: 500px) {
  .card h2 {
    font-size: 2em;
    color: gray;
  }
}

<div class="container">
  <div class="card">
    <h2>Card title</h2>
  </div>
</div>

Example

Enumerable#any? and Enumerable#detect

Someone told me #any? didn't stop iterating after finding the first truthy value, that I should use #detect instead, but turns out both methods behave the same, at least in Ruby 3.0.1.

Try running this for example:

(1..5).to_a.any? do |n|
  puts n
  true
end

(1..5).to_a.detect do |n|
  puts n
  true
end

You'll see this:

1
1

to install ruby 2.4.6 on a Mac m1 with rbenv

Once upon a time (even thouhg we have newer versions of ruby) I had to install an older version of ruby, the 2.4.6 on my Mac M1 (OS X 12.6), I was having this problem:

ruby-build: using readline from homebrew

BUILD FAILED (macOS 12.6 using ruby-build 20220910.1)

So after googling I found that we can do this:

CFLAGS="-Wno-error=implicit-function-declaration" RUBY_CONFIGURE_OPTS='--with-readline-dir=/usr/local/opt/readline/' arch -x86_64 rbenv install 2.4.6

and it worked!

that's it bye!

Tell apt to keep the current version of a package

If you ever need apt to keep the current version of a package, use hold:

sudo apt-mark hold <package>

This will prevent apt from upgrading the package. You can always unhold it back when you want to upgrade it.

Always use retry inside rescue blocks

Ruby includes a retry keyword that would bring execution back to the start of the current method while preserving scope. But what if you do this?

def my_method
  my_var = 1
  retry
end

That would fail with an Invalid retry, which is one of the few illegal statements in Ruby.

retry is only allowed inside rescue blocks.

def my_method
  my_var = 1
  raise Exception
rescue Exception
  retry
end

How to use object destructuring with the index over an array?

const names = ['Roy', 'Liz', 'Sofia', 'Clau']

const {
  0: zero,
  1: one,
  2: two,
  3: three,
} = names

console.log(zero) // 'Roy'

How to rebase all reachable commits including the first commit?

git rebase -i --root

Fr Unit with CSS Grid Layout

I read about CSS Grid Layout, and I found the Fr unit, so I have to try it out.

From w3.org:

Flexible Lengths: the fr unit A flexible length or is a dimension with the fr unit, which represents a fraction of the leftover space in the grid container. Tracks sized with fr units are called flexible tracks as they flex in response to leftover space similar to how flex items with a zero base size fill space in a flex container.

The distribution of leftover space occurs after all non-flexible track sizing functions have reached their maximum. The total size of such rows or columns is subtracted from the available space, yielding the leftover space, which is then divided among the flex-sized rows and columns in proportion to their flex factor.

Each column or row’s share of the leftover space can be computed as the column or row’s * / .

Behavior of Capybara's "have_no_content" when expected with `.to_not` and with `.to`

about to_not have_content:

  expect(page).to_not have_content("not on page")

it waits (Capybara's default waiting time), then it pass. Don't use it! 🚫

whereas to have_no_content:

  expect(page).to have_no_content("not on page")

Waits (same as with .to_not) but it passes as soon as "not on page" disappears from the page; use this one to wait for loading messages to disappear! ✅

data-scheme to add styles!

If you need to add styles to an element when the page is in dark mode, simply use the data-scheme of the page followed by the class or ID of the element you want to add styles to.

[data-scheme="dark"] .js-subs-text-inputs {
   color: #FFFFFF;
}

Always check ACLs if something is fishy!

If you ever encounter a Linux dir in which you cannot write even when you're sure you have write permissions on it, check the ACLs. You may find someone doesn't particularly like you. 😞

-> getfacl /tmp 
# file: tmp
# owner: root
# group: root
# flags: --t
user::rwx
group::rwx
other::rwx
user:my_user:--- # this means "screw u and only u"

Defining classes using full name vs wrapping them inside modules

In Ruby, we can write classes inside modules. We usually do this to have classes namespaced to the module, so we don't risk two different classes having the same name. This is important since Ruby won't complain about re-defining a class, it would just open it and add new methods to it.

We could write classes using their full name, like this:

class Pokemon::Game::SpecialAttack < Pokemon::Game::Attack
  # ...
end

or, we could wrap the whole thing using modules, like this:

module Pokemon
  module Game
    class SpecialAttack < Attack # Ruby looks for SpecialAttack inside Pokemon::Game automatically!
      # ...
    end
  end
end

Both methods work the same, except the one above can only reference Attack using its whole name. On the other hand, it looks somewhat easier to read than nesting modules inside other modules. Which style do you prefer?

Upgrade your SSH keys from RSA to ED25519

ssh-rsa is the most common public/private key type, but is widely considered insecure with key lengths lower than 2048 bits. If you created your SSH key using ssh-keygen with default options a while ago, chances are you're using an unsafe key. Furthermore, support for RSA host keys (keys that identify the server you're trying to connect to) is disabled by default since OpenSSH 8.8 and they may consider disabling the algorithm altogether in the future.

But don't worry! Just create a new key for yourself using the most recommended key type available today: ED25519.

ssh-keygen -t ED25519 -a 100 -C "myemail@email.com"

Just make sure you got OpenSSH 6.5 or greater on both ends. Don't forget to install your new key and remove the old one!