Day 27: Jenkins Part 4 - Jenkins Job Overview: Understanding Each Field in Detail

Introduction to Jenkins Jobs

A Jenkins job encapsulates a specific task or process within the CI/CD pipeline. Whether it's compiling source code, running tests, or deploying applications, Jenkins jobs define and execute these tasks automatically. When configuring a Jenkins job, users encounter a variety of fields, each serving a distinct purpose in defining job behavior and characteristics.

Let's delve into each field of a Jenkins job:

Click on the new item in dashboard to create a new job.I had created new job as demopriyanka-project.

1. General:

The "General" option in Jenkins allows users to configure basic settings for a job, including its name, description, triggering conditions, and concurrent build behavior, providing essential parameters for job execution and management.

• Job Name: The unique identifier for the Jenkins job, helping users distinguish between different jobs.
• Description: Provides a brief description of the job, aiding in understanding its purpose and functionality.
• Discard Old Builds: Configures the retention strategy for old builds, allowing users to control disk space usage.
• GitHub Project: Links the Jenkins job to a GitHub repository, enabling integration with version control systems.
• This project is parameterized: Allows users to define parameters for the job. Parameters enable customization and flexibility in job execution, such as specifying build versions, environment variables, or user inputs during job execution.
• Throttle builds: Allows users to limit the concurrent execution of the job, preventing overload on resources by restricting the number of simultaneous builds.
• Execute concurrent builds if necessary: permits the job to run multiple builds simultaneously if there's a demand, helping to maximize throughput.

• Advanced Option: The "Advanced" option enables users to specify additional parameters for concurrent builds, such as defining a maximum number of concurrent builds or configuring build throttling strategies based on resource availability.

2. Source Code Management (SCM):

In Jenkins, the purpose of the Source Code Management (SCM) option is to specify the version control system and repository details where the source code of the project is stored. It allows Jenkins to retrieve the latest code changes, facilitating automated builds, tests, and deployments within the CI/CD pipeline.

• Git, Subversion, Mercurial: Selects the version control system for the Jenkins job, allowing users to specify the repository URL and credentials.
• Branches to Build: Defines the branches to be monitored and built by Jenkins, facilitating branch-specific builds and workflows.
• Additional Behaviors: Offers advanced options such as polling, shallow clones, and custom SCM behaviors to tailor SCM configuration.

3. Build Triggers:

In Jenkins, the "Build Trigger" option allows users to define conditions or events that automatically initiate the execution of a Jenkins job, facilitating continuous integration and automation of software builds in response to changes in source code repositories, scheduled intervals, or external triggers.

• Trigger builds remotely (e.g., from scripts) : Allows external scripts or systems to initiate job builds via HTTP requests, enabling automation and integration with external tools or services.
• Build after other projects are built: Allows a job to be triggered automatically after the completion of specified upstream projects, enabling sequential execution of related jobs in the CI/CD pipeline.
• Build Periodically: Defines a schedule for triggering builds at specified intervals, ensuring regular execution of the Jenkins job.
• GitHub hook trigger for GITScm polling: Initiates builds automatically upon detecting changes in the linked GitHub repository or SCM.
• Poll SCM: Regularly checks the source code repository for changes based on a defined schedule. If changes are detected, it triggers a build, ensuring that the job stays synchronized with the source code repository.

4. Build Environment

The "Build Environment" option in Jenkins allows users to configure the runtime environment for the build, including settings like workspace cleanup, environment variable injection, and build execution conditions.

• Delete workspace before build starts: Clears the workspace directory before starting the build, ensuring a clean environment for each execution.

• Use secret text(s) or file(s): Provides options for injecting secrets and credentials into the build environment securely.

• Add timestamps to the Console Output: Adds timestamps to the console output of the build, providing a chronological record of build execution events for analysis and troubleshooting.
• Inspect build log for published build scans: Allows for the automatic detection and analysis of published build scans within the build log, aiding in identifying and reviewing detailed scan reports for improved build quality and security.
• Terminate a build if it's stuck: Aborts the build if it exceeds a specified timeout threshold, preventing stuck builds from consuming resources indefinitely.
• With Ant : Allows users to specify Ant build scripts to be executed as part of the build process, facilitating integration with Ant-based projects for compilation, testing, and deployment tasks.

5. Build Steps:

In Jenkins, build steps define the specific actions or tasks to be executed during the build process. There are various build step options available, each serving different purposes. Let's explore them in detail:

• 1. Execute Shell: This build step allows users to execute shell commands on Unix-based systems or batch commands on Windows systems. It's a versatile option for running custom scripts, executing commands, and performing various tasks during the build process.2. Execute Windows batch command: Similar to the "Execute Shell" step but specific to Windows systems, this option enables users to run batch commands or scripts written in the Windows Command Prompt language (CMD).3. Invoke Ant: This option allows users to execute Ant build scripts as part of the build process. Users can specify the location of the build file (e.g., build.xml) and any additional targets to be invoked. Ant is a popular build tool used primarily for Java projects.4. Invoke Gradle script: Similar to the "Invoke Ant" option, this build step allows users to execute Gradle build scripts. Users can specify the location of the Gradle script (e.g., build.gradle) and any additional tasks to be executed. Gradle is a build automation tool used for building various types of projects.5. Invoke Maven: This option enables users to execute Maven build commands. Users can specify Maven goals and options to be executed during the build process. Maven is a widely-used build automation tool primarily for Java projects, managing dependencies, compiling code, running tests, and packaging artifacts.6. Run with timeout: This build step allows users to run a specified build step with a timeout limit. If the build step exceeds the specified timeout, the build will be aborted. It helps prevent stuck builds and ensures timely completion of build processes.7. Publish JUnit test result report: This option allows users to publish JUnit test results generated during the build process. Users can specify the location of the XML test result files and configure options for parsing and displaying test results in Jenkins.8. Archive the artifacts: This build step enables users to archive build artifacts produced during the build process. Users can specify files or directories to be archived, making them accessible for downstream jobs, deployment, or future reference.9. Inject environment variables: This option allows users to inject environment variables into the build process. Users can specify key-value pairs of environment variables to be set during the build, facilitating configuration and customization of build environments.10. Execute system Groovy script: This build step allows users to execute system-level Groovy scripts within the Jenkins environment. It provides advanced scripting capabilities for automation, customization, and integration with Jenkins APIs.Each build step in Jenkins plays a crucial role in defining the actions and tasks to be performed during the build process. By leveraging these options effectively, users can automate build tasks, streamline development workflows, and ensure the efficiency and reliability of their CI/CD pipelines.

6. Post-build Actions:

In Jenkins, post-build actions are tasks or operations that occur after the completion of a build. They allow users to perform various actions based on the outcome of the build, such as archiving artifacts, sending notifications, and triggering downstream jobs. Let's explore the post-build actions options in detail:

1. Archive the artifacts:Archives build artifacts, such as compiled binaries, reports, and documentation, for future reference and deployment.Users specify files or directories to be archived, making them accessible for downstream jobs or manual download.
2. Trigger parameterized build on other projects:Triggers downstream Jenkins jobs with parameters, allowing users to initiate subsequent builds based on the outcome of the current build.Users specify the target project, parameters, and conditions for triggering the downstream job.
3. Build other projects:Initiates the execution of other Jenkins projects or jobs after the completion of the current build.Users specify the target project(s) to be built and any additional parameters or conditions.
4. Set build status to "pending" on downstream projects:Sets the build status of downstream projects to "pending" until the current build completes successfully.Ensures that downstream projects do not start executing until all upstream dependencies are met.
5. Record fingerprints of files to track usage:Records fingerprints of specified files to track their usage across builds and downstream jobs.Helps in identifying dependencies and tracking changes to files throughout the build pipeline.
6. Send build artifacts over SSH:Transfers build artifacts securely over SSH (Secure Shell) to remote servers or destinations.Users specify SSH configurations, target servers, and destination paths for artifact transfer.
7. Deploy artifacts to Artifactory:Deploys build artifacts to an Artifactory repository for artifact management and distribution.Users configure Artifactory server settings, repository paths, and authentication credentials.
8. Email notification:Sends email notifications to specified recipients based on the outcome of the build (success, failure, unstable, etc.).Users configure email settings, recipient lists, content templates, and triggers for sending notifications.
9. Publish JUnit test result report:Parses and displays test results from JUnit-compatible test reports generated during the build process.Users specify the location of the test result files and configure options for parsing and displaying test results.
10. Publish HTML reports:Publishes HTML reports generated during the build process, allowing users to share build artifacts and documentation.Users specify the location of HTML files and configure options for publishing reports.

These post-build actions in Jenkins provide users with flexibility and automation capabilities to enhance their CI/CD workflows, improve visibility into build results, and streamline the software delivery process. By configuring appropriate post-build actions, users can automate tasks, facilitate collaboration, and ensure the quality and reliability of their software projects.

Conclusion

Understanding the Jenkins job configuration is essential for optimizing CI/CD workflows and streamlining software development processes. By leveraging the diverse range of fields within a Jenkins job, users can automate tasks, orchestrate complex build pipelines, and ensure the reliability and efficiency of their software delivery pipelines.

Build the above created demopriyanka-project job by keeping Poll SCM as 1 minute and here is the Console output:

In this guide, we've explored the significance of each field within a Jenkins job, providing insights into their usage, importance, and implications for CI/CD practices. By mastering Jenkins job configuration, users can harness the full potential of Jenkins as a versatile automation platform for software development and delivery.