Jenkins’s dsl(domain specific language) Groovy

5 min readSep 6, 2020

Jenkins: jenkins is the devops tool which helps to automation of projects , by which projects are tracked and done automatically. jenkins can be used as integration tool also . By jenkins many devops tool are integrated and done project in loop automaticaly without using more human resources .

In devops when developer wants to configure job in jenkins without access login ID and password then dsl(domain specific language )is used for configuration job .

Jenkins support groovy language because groovy support java and jenkins already have java .

When a job is configured for downloading code from github then developer upload code for job configuration that is written in groovy language . After download code from github automatic a job is created .

Task description:

Perform task with the help of Jenkins coding file ( called as jenkinsfile approach ) .

First of all created container image that’s has jenkins installed using dockerfile .

First of all created a directory “devops_task6” using cmd

mkdir devops_task6

After creating directory go to that directory and create a Dockerfile for image creating that has jenkins installed and have power to operate kubernetes resources

cd devops_task6

Dockerfile:

After creating Dockerfile run below cmd to create image

docker build -t jenkins_image:v2 .

After creating image tagged a name with image name and upload on github.

docker tag jenkins_image:v2 firsttalk26/jenkins_image:v2 
docker push firsttalk26/jenkins_image:v2

After uploading image on github , i have created deployment configuration file for deployment of jenkins on kubernetes .

jenkins_deployment.yml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: jenkins-deployment
  labels:
    app: jenkins
spec:
  replicas: 1
  selector:
    matchLabels:
      app: jenkins
  strategy:
    type: Recreate
  template:
    metadata:
      labels:
        app: jenkins
    spec:
      containers:
      - image: firsttalk26/jenkins_image:v2
        name: jenkins
        ports:
        - containerPort: 8080
          name: jenkins
        volumeMounts:
        - name: jenkins-pvc
          mountPath:
            /root/.jenkins
      volumes:
      - name: jenkins-pvc
        persistentVolumeClaim:
          claimName: jenkins-pvc

jenkins_pvc.yml

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: jenkins-pvc
  labels:
    name: jenkinspvc
spec:
  accessModes:
  - ReadWriteOnce
  resources:
    requests:
      storage: 1Gi

jenkins_service.yml

apiVersion: v1
kind: Service
metadata:
  name: jenkins-service
  labels:
    app: jenkinsService
spec:
  ports:
    - port: 8080
      nodePort: 30006
  selector:
    type: jenkins
  type: NodePort

For launch jenkins deployment , service and pvc run below cmd

kubectl create -f jenkins_pvc.yml
kubectl create -f jenkins_deployment.yml
kubectl create -f jenkins_service.yml

After launch pod of jenkins open jenkins dashboard using url and created job for complete project .And created three job

Job in jenkins:

Parentjob: Pull the repo from github automatically when some developers push repo on github , and job is created using written code in groovy language by the developer .

Job1: Pull the github repo automatically when some developers push repo on github , and copy in the folder task6_data

Job2: By looking on the code or programme file , jenkins should automatically start the respective language interpreter installed image container to deploy code on top of kubernetes .

Job3: Test app , it is working or not . If app is not working then sent email to developer with error messages

First of all i have created a code file using groovy language and i have uploaded on github .

Task6.groovy:

job("task6_job1"){
  description("my first dsl job")
  scm{
    github('firsttalk26/devops1','master')
  }
  triggers{
    scm("* * * * *")
  }
  steps{
    shell('''if ls /root/.jenkins/workspace/ | grep task6_data
then
  cp -rf * /root/.jenkins/workspace/task6_data/
  echo "folder created"
else
  sudo mkdir /root/.jenkins/workspace/task6_data
  cp -rf * /root/.jenkins/workspace/task6_data/
fi''')
    
    }
}
job("task6_job2"){
  description("my 2nd dsl job")
  triggers{
    upstream("task6_job1",'SUCCESS')
  }
  steps{
    shell('''if ls /root/.jenkins/workspace/task3_data/ | grep .html
then
  if kubectl get deployment | grep webserver-deployment 
  then
    echo "already webserver-deployment created"
  else
    kubectl create -f /root/.jenkins/workspace/task3/webserver_deployment.yml
  fi
else
  echo "it's not html code"
  if ls /tas3/ | grep .phpcode
  then
    echo " it is php code"
    if kubectl get deployment | grep webapp-deployment
    then
      echo " webapp-deployment is already created"
    else
      kubectl create -f /root/.jenkins/workspace/task3/php.yml
    fi
  else
    echo "recheck code"
  fifi''')
    }
}
job("task6_job3"){
  description("my 3rd dsl job")
  triggers{
    upstream("task6_job2",'FAILURE')
  }
  steps{
    shell('''podname=$(kubectl get pods -l type=html --output=jsonpath={.items..metadata.name})kubectl cp /root/.jenkins/workspace/task3_data/  $podname:/usr/local/apache2/htdocs/status=$(curl -o /dev/null -s -w "%{http_code}" http://192.168.99.109:30001)
if [ $status == 200 ]
then
  exit 0
else
  exit 1
  
fi
''')
  
    }
  publishers{
  mailer("firsttalk26@gmail.com", false, false)
  }
}