Demo Refactoring Jenkinsfile

In this guide, we’ll walk through refactoring a Jenkins pipeline to:

Simplify credential handling
Remove duplicate withCredentials blocks
Centralize test report and HTML publishing in a post section

This approach reduces boilerplate and improves maintainability of your Jenkinsfile.

Original Jenkinsfile Snippet

Both the Unit Testing and Code Coverage stages currently use identical withCredentials wrappers:

pipeline {
    agent any

    environment {
        MONGO_URI = "mongodb+srv://supercluster.d83jj.mongodb.net/superData"
    }

    options {
        // ...
    }

    stages {
        stage('Installing Dependencies') { /* ... */ }
        stage('Dependency Scanning')  { /* ... */ }

        stage('Unit Testing') {
            options { retry(2) }
            steps {
                withCredentials([usernamePassword(
                    credentialsId: 'mongo-db-credentials',
                    passwordVariable: 'MONGO_PASSWORD',
                    usernameVariable: 'MONGO_USERNAME'
                )]) {
                    sh 'npm test'
                }
            }
            junit allowEmptyResults: true, testResults: 'test-results.xml'
        }

        stage('Code Coverage') {
            steps {
                withCredentials([usernamePassword(
                    credentialsId: 'mongo-db-credentials',
                    passwordVariable: 'MONGO_PASSWORD',
                    usernameVariable: 'MONGO_USERNAME'
                )]) {
                    sh 'npm run coverage'
                }
                publishHTML(
                    allowMissing: true,
                    alwaysLinkToLastBuild: true,
                    keepAll: true,
                    reportDir: 'coverage/lcov-report',
                    reportFiles: 'index.html',
                    reportName: 'Code Coverage HTML Report'
                )
            }
        }
    }
}

root@jenkins-controller-1 in solar-system on ⬢ feature/enabling-cicd via 🐍 v20.16.0
>

1. Injecting Credentials via `environment`

Instead of wrapping every stage in withCredentials, Jenkins can populate environment variables automatically:

Environment Variable	Value
`MY_CREDS`	`username:password`
`MY_CREDS_USR`	`username`
`MY_CREDS_PSW`	`password`

The image shows a webpage from the Jenkins documentation, specifically focusing on using a Jenkinsfile with credential environment variables. It includes code snippets and explanations about handling credentials in a Jenkins pipeline.

Define a Single Credential

pipeline {
    agent any

    environment {
        MONGO_DB_CREDS = credentials('mongo-db-credentials')
    }

    stages {
        stage('Unit Testing') {
            options { retry(2) }
            steps {
                // No explicit withCredentials needed
                sh 'npm test'
            }
            junit allowEmptyResults: true, testResults: 'test-results.xml'
        }
    }
}

Note

You can echo these variables to confirm that Jenkins injects them correctly, but remember that secrets remain masked in logs.

stage('Unit Testing') {
    options { retry(2) }
    steps {
        sh 'echo Colon-Separated → $MONGO_DB_CREDS'
        sh 'echo Username → $MONGO_DB_CREDS_USR'
        sh 'echo Password → $MONGO_DB_CREDS_PSW'
        sh 'npm test'
    }
    junit allowEmptyResults: true, testResults: 'test-results.xml'
}

root@jenkins-controller-1 in solar-system on ⬢ feature/enabling-cid via ⬢ v20.16.0

2. Why the Stage Fails

After pushing, the build fails:

The image shows a Jenkins pipeline interface with a visual representation of a build process, highlighting a failed unit testing step. It includes details of the steps executed and their status.

Although the variables are injected:

$MONGO_DB_CREDS is masked
$MONGO_DB_CREDS_USR is displayed
$MONGO_DB_CREDS_PSW is masked

Your test suite still expects MONGO_USERNAME and MONGO_PASSWORD, so the stage cannot authenticate.

3. Defining Separate Secret-Text Credentials

To match your test code, split the single credential into two Secret text entries:

In Jenkins UI, go to Credentials > Global.
Add Secret text credentials:
- ID: mongo-db-username → MongoDB username
- ID: mongo-db-password → MongoDB password

The image shows a Jenkins interface displaying a list of global credentials, including Gitea server and MongoDB credentials, with options to add or edit them.

Update the environment block accordingly:

pipeline {
    agent any

    environment {
        MONGO_URI      = "mongodb+srv://supercluster.d83jj.mongodb.net/superData"
        MONGO_DB_CREDS = credentials('mongo-db-credentials')     // optional composite
        MONGO_USERNAME = credentials('mongo-db-username')
        MONGO_PASSWORD = credentials('mongo-db-password')
    }

    stages {
        stage('Unit Testing') {
            options { retry(2) }
            steps {
                sh 'echo DB Creds    → $MONGO_DB_CREDS'
                sh 'echo Username    → $MONGO_USERNAME'
                sh 'echo Password    → $MONGO_PASSWORD'
                sh 'npm test'
            }
            junit allowEmptyResults: true, testResults: 'test-results.xml'
        }

        stage('Code Coverage') {
            steps {
                catchError(buildResult: 'SUCCESS', stageResult: 'UNSTABLE') {
                    sh 'npm run coverage'
                }
                publishHTML(
                    allowMissing: true,
                    alwaysLinkToLastBuild: true,
                    keepAll: true,
                    reportDir: 'coverage/lcov-report',
                    reportFiles: 'index.html',
                    reportName: 'Code Coverage HTML Report'
                )
            }
        }
    }
}

4. Centralizing Reports in `post { always { ... } }`

Rather than repeating junit and publishHTML in each stage, use a post block to archive all reports after every build:

pipeline {
    agent any

    environment { /* ... */ }
    options     { /* ... */ }

    stages {
        stage('Installing Dependencies')     { /* ... */ }
        stage('Dependency Scanning')          { /* ... */ }
        stage('OWASP Dependency Check')       { /* ... */ }
        stage('Unit Testing')                 { /* ... */ }
        stage('Code Coverage')                { /* ... */ }
    }

    post {
        always {
            junit allowEmptyResults: true, testResults: 'test-results.xml'
            junit allowEmptyResults: true, testResults: 'dependency-check-junit.xml'
            publishHTML(
                allowMissing: true,
                alwaysLinkToLastBuild: true,
                keepAll: true,
                reportDir: 'coverage/lcov-report',
                reportFiles: 'index.html',
                reportName: 'Code Coverage HTML Report'
            )
            // Add additional publishHTML calls as needed
        }
    }
}

Warning

Don’t forget to adjust testResults patterns if you rename or relocate report files—otherwise Jenkins may skip them.

5. Run the Refactored Pipeline

With credentials injected at the top and reports centralized, the build should now succeed:

> npm test
> mocha app-test.js --timeout 10000 --reporter mocha-junit-reporter --exit
Server successfully running on port - 3000
...
> npm run coverage
...
[htmlpublisher] Archiving HTML reports...
...

Final Full Example

pipeline {
    agent any

    environment {
        MONGO_URI      = "mongodb+srv://supercluster.d83jj.mongodb.net/superData"
        MONGO_DB_CREDS = credentials('mongo-db-credentials')
        MONGO_USERNAME = credentials('mongo-db-username')
        MONGO_PASSWORD = credentials('mongo-db-password')
    }

    options {
        // ...
    }

    stages {
        stage('Installing Dependencies')    { /* ... */ }

        stage('Dependency Scanning')        { /* ... */ }

        stage('Unit Testing') {
            options { retry(2) }
            steps {
                sh 'echo DB Creds    → $MONGO_DB_CREDS'
                sh 'echo Username    → $MONGO_USERNAME'
                sh 'echo Password    → $MONGO_PASSWORD'
                sh 'npm test'
            }
        }

        stage('Code Coverage') {
            steps {
                catchError(buildResult: 'SUCCESS', stageResult: 'UNSTABLE') {
                    sh 'npm run coverage'
                }
            }
        }
    }

    post {
        always {
            junit allowEmptyResults: true, testResults: 'test-results.xml'
            junit allowEmptyResults: true, testResults: 'dependency-check-junit.xml'
            publishHTML(
                allowMissing: true,
                alwaysLinkToLastBuild: true,
                keepAll: true,
                reportDir: 'coverage/lcov-report',
                reportFiles: 'index.html',
                reportName: 'Code Coverage HTML Report'
            )
            // Add other publishHTML steps here
        }
    }
}

Links and References

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