First time trying with Kafka Install Kafka on Mac locally brew install --cask java brew install kafka Run Zookeeper and Kafka brew services start zookeeper brew service start kafka Create topic kafka-topics --create --zookeeper localhost:2181 --replication-factor 1 --partitions 1 --topic test-sk Run producer console kafka-console-producer --broker-list localhost:9092 --topic test-sk Write each message into the topic separate by pressing ENTER; then press CTR+C to exit…

from rubyist perspective Everything in go pass by value Go variable without defining if it is integer it will be zero by default if it is boolean it will be false by default if it is string it will be empty string Naked return Normal return func Hello() (string) { hello := "hello" return hello } Naked return func Hello() (hello string)…

Why on VM instead of using GCP Memorystore? — We can create Redis instance via Memorystore but with Memorystore we cannot connect to redis instance from outside ip address. Setup VM Follow tutorial to create VM on google cloud platform. Enable Static Ip Address By default external ip address of a VM is changed from time to time. We need to set it statically. Setup Firewall Rule for VM In…

Should avoid it when possible because its abstraction is not clear. The method such as after_save, before_save…etc. don’t have a clear purpose of the business logic rather than CRUD. It applies whenever before or after save active record object. Even you have conditional callback, it will exist in model or…

I found some funny quotes about math and this one is my favorite. I stopped understanding math when the alphabet decided to get involved. Being said that, this one makes sense too. So let’s find the combination of two selections from gratitude, responsibility, freedom and love. Even I say gratitude…

Ruby Module and Class (Mix-in vs Inheritance) That would be tricky to decide when to use module or inheritance in Ruby or any other language (behavior vs is-a relationship). Use the module if the class has many behaviors and use the module when you tend not to have instantiated objects. Use inheritance if the class belongs to…

Catastrophic Consequence of Prepared Statement in Rails < 5 Rails has prepared statement limit to 1000 per connection and cache in the memory, which could cause memory leak issue. When we run migration remove/adding new column, it could cause the prepared statement cache to be invalid and cause fail in execution. Fix: retry. …

YAGNI vs Martin’s OCP and Meyer’s OCP YAGNI is talking about up front software feature. Martin’s OCP is about code ripple effect. Meyer’s OCP is about API backward compatibility. Framework Design: Dependency Injection, Inversion of Control and AOP DI is to inject instantiate object from DI container into a method. Decoupling in the implementations. DI is the technique to wire object together in the flexible way…

Heroku Dyno The Heroku Platform uses the container model to run and scale all Heroku apps. The containers used at Heroku are called “dynos.” Dynos are isolated, virtualized Linux containers that are designed to execute code based on a user-specified command. Source: https://www.heroku.com/dynos Stack Vs Heap Stack is very fast to access. Space is auto…