Jenkins

Jenkins

Tools

• in jenkins tools help us to use the commands of the software required
• There are two possible ways of to these:
  1. Installing a plugin
  2. Installing the tools directly on that server itself both these methods ensure that the command required by the application is accessible throughout the jenkins

JOBS

Jenkins Freestyle Job

• The most basic job type in Jenkins
• Straightforward to set up and configure -suitable for simple, small-scale projects
• Lack some advanced features provided by newer job types

Note :

• there occurs an error when you try to install nodejs. via the command that is present in the offical website
• the below command has worked perfectly. The reason is still unknown for me

  # As root, install Node.js system-wide (example using apt)
  curl -fsSL https://deb.nodesource.com/setup_18.x | bash -
  apt-get install -y nodejs
  

Attaching the docker directory of host to the container to access docker in the container through a volume

docker run -p 8080:8080 -p 50000:50000 -d \
> -v jenkins_home:/var/jenkins_home \
> -v /var/run/docker.sock:/var/run/docker.sock --name updates_jenkins \
> jenkins/jenkins:lts

curl https://get.docker.com/ > dockerinstall && chmod 777 dockerinstall && ./dockerinstall

docker.sock file is a Unix socket file, used by the Docker daemon to communicate with the Docker client

chmod 666 /var/run/docker.sock

JENKINS PIPELINE JOB

• Pipelines are scripted
• script is written in groovy
• groovy is similar to java
• best practice is to have the script in the source code management

Pipeline Syntax

• Requires Fields in jenkins declarative script
  • ‘pipeline” must be top-level
  • “agent” - where to execute
  • “stages” - where the “work” happens
    • “stage” and “steps”

Jenkins File Syntax

pipeline {

    agent any
    environment{
	    NEW_VERSION = '1.3.0'
	    }
    stages {

        stage('Build') {

            steps {

                echo 'Building...'

                // Add your build commands here

            }

        }

        stage('Test') {

            when {

                expression { return env.BRANCH_NAME == 'main' }

            }

            steps {

                echo 'Testing...'

                // Add your test commands here

            }

        }

        stage('Deploy') {

            steps {

                echo 'Deploying...'

                // Add your deployment commands here

            }

        }

    }

  

    post {

        always {

            echo 'This will always run after the pipeline completes.'

        }

        success {

            echo 'This will run only if the pipeline succeeds.'

        }

        failure {

            echo 'This will run only if the pipeline fails.'

        }

    }

}

Environment Variables in Jenkins File

https://jenkins.bitinfra.in/enn-vars.html

Tools for Pipeline

• For now tools support maven, jdk and gradle

Parameters

  parameters {

        choice(name: 'ENVIRONMENT', choices: ['development', 'staging', 'production'], description: 'Select the environment to deploy')

        string(name: 'BRANCH_NAME', defaultValue: 'main', description: 'Branch to build')

        booleanParam(name: 'RUN_TESTS', defaultValue: true, description: 'Run tests after build')

    }