DevOps Classroomnotes 25/Feb/2023

Jenkins

Story of Jenkins

Need for Continuous Integration

• Traditional Software Project Lifecycle
  
• Big Bang Integrations, were used by teams traditionally to combine components as each component was built by teams in isolation.
  
• Result of BigBang
  
• Continuous Integration (CI): In this we integrate all the components of the application from day 1. Ideally whenver developer pushes the code to remote repository we need to perform integration.
• To check whether CI is successful or not a small set of automated tests were developed i.e.
  • We build all the application components
  • integrate them and run this small set of tests which checks basic functionality of the system (Smoke Tests)
• Developers have started writing unit tests (test code which tests the application code)
• To measure the accuracy of unit tests generally we need a tool which measures coverage i.e. code coverage
• Code Coverage: Generally these are measure by tools
  • Line Coverage
  • branch coverage
  • symbol Coverage
• To verify the quality of code and whether it suits your organization’s coding standards, Code Reviews are conducted.
• For coding standards and best practices we can use tools. The failures represented by these tools are generally referred as
  • Technical debt
  • Code Smell
• The tool for running tests is called as test harness tool or popularly know as test runners. For running unit tests
  • junit (java)
  • pytest (python)
  • jasmine (nodejs)
  • nunit (c-sharp)
• To check code coverage and code qualilty we have a tool which are generally referred as Static Code Analysis Tools. We will be using Sonar Qube
• We need a tool which whenever a code is pushed to vcs, builds the code, runs the unit tests and also generates Static Code Analysis report. These tools are referred as CI/CD Engines. Some of the popular CI/CD Engines are
  • Jenkins
  • Azure DevOps Pipelines
  • Travis CI
  • Team City
  • Bamboo

Build and Artifact

• Build represents a format/package into which your application code is transformed to run on enduser systems.
• To Generate Package we need to perform certain steps
  • compile
  • package

Building Java

• To make it simple to build java code , Apache foundation has created a tool called as Ant
• In Ant we configure the build using build.xml Refer Here
• Then a tool called as Maven was released which can perform
  • build
  • packaging
  • dependency management
  • documenation
• Maven goes with Convention over Configuration and all of them are around a file which is referred as pom.xml (project object model)
• Maven has a lifecycle
  • validate
  • compile
  • test
  • package
  • install
  • deploy
  • clean
    
• Every CI/CD Engine is Cron on steriods
  

Dependencies

• All the development projects depend on external libraries
  • Java: maven packages
  • node js: npm packages
  • python: pip packages
  • dotnet: nuget packages
• There is a need for managing dependencies