TILs - Fueling Curiosity, One Insight at a Time

Ruby has a class called SimpleDelegator which can be used to used to implement decorator pattern. It can be used to delegate all supported method calls to the object passed into the constructor.

You can use a tool called [Telepresence](https://www.telepresence.io) to create a 2-way proxy between your local dev machine and a k8s cluster. Uses : be able to inherit env vars and other configs from k8s locally, make use of other services running in the cluster when running your dev instance of a service you want to test

Arel is a SQL abstract syntax tree manager for ruby. It helps to simplify creating complex SQL queries and interfaces with various RDBMS. Arel modifies it's AST nodes based on the methods you call on it and ActiveRecord makes use of this to build composable chainable queries and then executes them. A detailed post on Arel: https://jpospisil.com/2014/06/16/the-definitive-guide-to-arel-the-sql-manager-for-ruby.html

You can speed up image builds by making use "--cache-from". This is useful when 1) you already have a previous version of the image which you can pull 2) docker pull is faster than docker build 3) intermediate layers in the previous version can be reused. This is useful for speeding up builds in docker container builder

There is something called QoS for pods using which we can prevent unwanted rescheduling of pods

you can use GCP cloud shell and use it to run kubectl commands instead of having to create a k8s context on your local kubectl CLI tool. This is very useful for doing some adhoc debugging on a k8s cluster you have access to. Just login to google cloud using google auth, and then click on "Connect" next to the cluster you want to connect to, then use cloud shell.

We can leverage structs in ruby to encapsulate and hold internal class data into a struct object. Since struct saves us from writing attr_accessor methods or initializer method, we can easily leverage it when in need of a temporary data structure and need to have the data grouped.

If you are using materialize, you need to initialize the select element with material_select(). Otherwise the select box will not get rendered.

Elixir and Erlang has a limit on the number of atoms that can be created. We can view the atom limit using :erlang.system_info(:atom_limit). Atom's text value is stored in the atom table and this is not garbage collected. This explains why user inputs to phoenix routes are to be matched with strings rather than atoms.

https://makandracards.com/makandra/5365-git-diff-staged-changes especially git diff --cached master is very useful,
1. if you do not like to look at web-ui for diff and
2. has a quite a bit code which you dont want to stage atm.

rubocop -a can autocorrect many kinds of issues.

ActiveRecord update_all does not touch updated_at

byebug

new design layout, pretty cool https://www.smashingmagazine.com/2018/05/guide-css-layout/

If one wants to run iex without starting any applications iex -S mix run --no-start is very handy

For models A and B, if A has_one B, then A.new.b.build wont work. You have to say A.new.build_b.

Sidekiq processes jobs in a multithreaded process. Which means there is no guarantee that the jobs that are enqueued will processed in the same order. So you'd need to consider the aspect of context switch that can happen and thus make sure that the worker code is thread safe.

Today I came to know that the name of process which takes care of clipboard is called pboard on mac. If clipboard is acting funny, just kill this process!