> ## Documentation Index > Fetch the complete documentation index at: https://notes.kodekloud.com/llms.txt > Use this file to discover all available pages before exploring further. # Demo Slack Get Failed Stage Name > Learn to identify failed stages in Jenkins Pipelines and send notifications to Slack without redundant failure blocks. In this lesson, you'll learn how to programmatically determine which stage failed in a Jenkins Pipeline and send that stage name to Slack—all without adding redundant `post { failure { … } }` blocks to every stage. ## Why Avoid Manual Post-Failure Blocks? Adding `post { failure { … } }` to each stage quickly becomes unmanageable as pipelines grow. Instead, we'll use the Jenkins Blue Ocean Plugin API at the end of the build to discover failed stages automatically. ## Programmatic Stage Discovery with Groovy Define two Groovy helper methods—`getStageResults` to collect stage data and `getFailedStages` to extract failures. Place these in a [Shared Library](https://www.jenkins.io/doc/book/pipeline/shared-libraries/) or at the top of your `Jenkinsfile`. The methods are annotated with `@NonCPS` to ensure they run outside the Pipeline CPS engine. ```groovy theme={null} import io.jenkins.blueocean.rest.impl.pipeline.PipelineNodeGraphVisitor import io.jenkins.blueocean.rest.impl.pipeline.FlowNodeWrapper import org.jenkinsci.plugins.workflow.steps.build.RunWrapper import org.jenkinsci.plugins.workflow.actions.ErrorAction @NonCPS List getStageResults(RunWrapper build) { def visitor = new PipelineNodeGraphVisitor(build.rawBuild) def stages = visitor.pipelineNodes.findAll { it.type == FlowNodeWrapper.NodeType.STAGE } return stages.collect { stage -> def errorActions = stage.getPipelineActions(ErrorAction) def errors = errorActions.collect { it.error }.unique() [ id : stage.id, failedStageName : stage.displayName, result : stage.status.result, errors : errors ] } } @NonCPS List getFailedStages(RunWrapper build) { getStageResults(build).findAll { it.result == 'FAILURE' } } ``` You can summarize these helper functions: | Method Name | Purpose | | --------------- | --------------------------------------------------- | | getStageResults | Collects every stage's ID, name, result, and errors | | getFailedStages | Filters the list to only include failures | ## Example Declarative `Jenkinsfile` Below is a sample pipeline illustrating how to use these methods in the `post` section. On failure, we extract the first failed stage name and embed it in a Slack alert. ```groovy theme={null} pipeline { agent any // Shared library or top of file: // getStageResults and getFailedStages stages { stage('Ok') { steps { echo 'This stage passes' } } stage('NotOK') { steps { sh 'exit 1' } } } post { always { publishHTML( allowMissing: false, alwaysLinkToLastBuild: true, keepAll: true, reportDir: 'owasp.zap.report', reportFile: 'index.html' ) } success { script { env.failedStage = 'none' env.emoji = ":white_check_mark: :tada: :thumbsup_all:" sendNotification(currentBuild.result) } } failure { script { def failedStages = getFailedStages(currentBuild) env.failedStage = failedStages[0]?.failedStageName env.emoji = ":x: :red_circle: :sos:" sendNotification(currentBuild.result) } } } } ``` ## Handling Jenkins Script Approval When running these API calls for the first time, Jenkins may block unapproved methods. Approve them via **Manage Jenkins → In-process Script Approval**. Ensure you only approve trusted methods. Unrestricted script approval can introduce security risks. ![The image shows a Jenkins console output with an error message indicating that scripts are not permitted to use a specific method due to security restrictions. The error details and stack trace are visible, suggesting a script approval issue.](https://kodekloud.com/kk-media/image/upload/v1752873789/notes-assets/images/DevSecOps-Kubernetes-DevOps-Security-Demo-Slack-Get-Failed-Stage-Name/jenkins-console-output-error-message.jpg) ![The image shows a Jenkins Script Approval page with options to approve or deny script permissions. It includes a list of methods and a warning about potential security vulnerabilities.](https://kodekloud.com/kk-media/image/upload/v1752873790/notes-assets/images/DevSecOps-Kubernetes-DevOps-Security-Demo-Slack-Get-Failed-Stage-Name/jenkins-script-approval-page-options.jpg) You may need to approve several entries until the build completes successfully. ## Verifying Failed Stages in Jenkins UI After granting approvals, rerun the pipeline. In the Classic UI's Stage View, failed stages are highlighted in red: ![The image shows a Jenkins pipeline dashboard with a stage view, displaying build history and stage times for a project. Some stages have failed, indicated by red highlights.](https://kodekloud.com/kk-media/image/upload/v1752873791/notes-assets/images/DevSecOps-Kubernetes-DevOps-Security-Demo-Slack-Get-Failed-Stage-Name/jenkins-pipeline-dashboard-stage-view.jpg) If additional methods are blocked, another console error will appear: ![The image shows a Jenkins console output with an error message indicating that scripts are not permitted to use a specific method due to security restrictions. There is also a stack trace detailing the error.](https://kodekloud.com/kk-media/image/upload/v1752873792/notes-assets/images/DevSecOps-Kubernetes-DevOps-Security-Demo-Slack-Get-Failed-Stage-Name/jenkins-console-output-error-message-2.jpg) Once all approvals are in place, check the overall pipeline view: ![The image shows a Jenkins pipeline dashboard for a project named "devsecops-numeric-application," displaying the stage view with build history and status of various stages, including some failed tests.](https://kodekloud.com/kk-media/image/upload/v1752873793/notes-assets/images/DevSecOps-Kubernetes-DevOps-Security-Demo-Slack-Get-Failed-Stage-Name/jenkins-pipeline-dashboard-devsecops-numeric.jpg) ## Slack Notifications on Failure When a stage fails, the Slack app will receive a message identifying the failed stage: ![The image shows a Slack interface with a Jenkins Slack App notification about a failed Kubernetes deployment in the "devsecops" pipeline. It includes details like job name, build number, failed stage, and Git information.](https://kodekloud.com/kk-media/image/upload/v1752873794/notes-assets/images/DevSecOps-Kubernetes-DevOps-Security-Demo-Slack-Get-Failed-Stage-Name/slack-jenkins-notification-kubernetes-failure.jpg) ## Confirming Success Notifications Use a simple two-stage pipeline to validate success notifications. Observe that `failedStage` is set to `none` on successful builds: ```groovy theme={null} pipeline { agent any stages { stage('Testing Slack - 1') { steps { sh 'exit 0' } } stage('Testing Slack - Error Stage') { steps { sh 'exit 1' } } } post { always { junit 'target/surefire-reports/*.xml' jacoco execPattern: 'target/jacoco.exec' dependencyCheckPublisher pattern: 'target/dependency-check-report.xml' } success { script { env.failedStage = 'none' env.emoji = ':white_check_mark: :tada: :thumbsup_all:' sendNotification(currentBuild.result) } } failure { script { def failedStages = getFailedStages(currentBuild) env.failedStage = failedStages[0]?.failedStageName env.emoji = ':x: :red_circle:' sendNotification(currentBuild.result) } } } } ``` A successful run will look like this in Slack: ![The image shows a Slack interface with a notification from the Jenkins Slack App about a successful Kubernetes deployment in the "devsecops" pipeline. It includes details like job name, build number, and links to Jenkins and GitHub.](https://kodekloud.com/kk-media/image/upload/v1752873795/notes-assets/images/DevSecOps-Kubernetes-DevOps-Security-Demo-Slack-Get-Failed-Stage-Name/slack-notification-jenkins-kubernetes-deployment.jpg) ## Conclusion Leveraging the Jenkins Blue Ocean API to detect failed stages keeps your pipeline concise and scalable. You’ll get accurate Slack alerts pinpointing the exact stage that failed—no repetitive `post { failure { … } }` blocks required. ## References * [Jenkins Pipeline Shared Libraries](https://www.jenkins.io/doc/book/pipeline/shared-libraries/) * [Blue Ocean Plugin API](https://github.com/jenkinsci/blueocean-plugin) * [Jenkins In-process Script Approval](https://www.jenkins.io/doc/book/managing/script-approval/) * [Slack Notification Plugin](https://plugins.jenkins.io/slack/)