Expert Web Development using React JS, Rails & Elixir

syedsibtain

Fri Apr 26 2024

In Ruby, instance variables are variables that belong to a specific instance of a class. They are prefixed with the @ symbol and are accessible within the instance methods of that class. Instance variables allow objects to maintain state and store information unique to each instance.
Example:


class Person
  def initialize(name, age)
    @name = name
    @age = age
  end

  def say_intro
    puts "Hello, my name is #{@name} and I am #{@age} years old"
  end
end

# Create a new instance of Person
person1 = Person.new("John", 18)

# Call the say_intro method
person1.say_intro

In this example, @name is an instance variable of the Person class, representing the name of each Person object created. The initialize method is a constructor that sets the value of @name when a new Person object is created. The say_intro method uses the instance variable @name to give the intro of the person with their name and age when called.

#ruby

nisanth

Thu Apr 25 2024

The docker stats command is a powerful tool provided by Docker to monitor the resource usage of running containers. It provides a real-time stream of various metrics such as CPU usage, memory usage, network I/O, block I/O, and the number of processes (PIDs) running inside each container. This command is particularly useful for performance analysis and ensuring that containers are running within their resource limits.
Example Explanation


docker stats db370fc6b784
CONTAINER ID   NAME       CPU %     MEM USAGE / LIMIT     MEM %     NET I/O          BLOCK I/O       PIDS
db370fc6b784   minikube   43.70%    1.243GiB / 2.148GiB   57.87%    35.4MB / 414MB

#devops #docker

vaibhav.yadav

Wed Apr 24 2024

We can check the default value for a given column using postgres query like this:


SELECT column_name, column_default
FROM information_schema.columns
WHERE table_name = '<table_name_placeholder>' AND column_name = '<column_name_placeholder>';

Same can be used for constraints like is_nullable as following:


SELECT column_name, is_nullable
FROM information_schema.columns
WHERE table_name = '<table_name_placeholder>' AND column_name = '<column_name_placeholder>';

#database #postgres #query