Interview Problem: CI/CD Pipeline for a Java Library Using Gradle

Scenario:

You are tasked with setting up a CI/CD pipeline for a Java library project. The project uses Gradle as the build tool, and the final output is a JAR file. The goal is to automate the build and testing process, and simulate publishing the JAR to a repository.

Your task is to configure a GitHub Actions workflow that automates the following steps whenever changes are merged into the main branch.

Requirements:

1. Build & Test:

   • Set up a GitHub Actions workflow that:
     • Runs unit tests on the Java library.
     • Builds the JAR file using Gradle.
   • Ensure the build fails if any tests fail or if there are issues with the build process.

2. Versioning:

   • Implement a simple versioning strategy:
     • Either manually set a version in the Gradle build script, or use the current Git commit hash as a version.

3. Simulated Publishing:

   • Instead of publishing to Sonatype, simulate the publishing process by:
     • Publishing the built JAR to a local Maven repository or simply packaging the JAR and uploading it as an artifact in the GitHub Actions workflow.
   • Outline how you would configure the pipeline to publish the JAR to Sonatype in a real-world scenario.

4. Notifications:

   • Configure the workflow to notify the team via email or Slack once the JAR is successfully built and "published."

Deliverables:

1. Pipeline Design:

   • Provide a brief written explanation or a diagram of the CI/CD pipeline design, detailing each step of the process.

2. Sample Workflow Configuration:

   • Implement a GitHub Actions workflow file (.yml) that:
     • Runs the build and test steps using Gradle.
     • Simulates the publishing process by either uploading the JAR as an artifact or publishing it to a local Maven repository.

3. Implementation Considerations:

   • Describe how you would handle:
     • Versioning to ensure that each built JAR has a unique version.
     • Managing sensitive information like repository credentials if this were a real deployment.

4. Bonus:

   • Suggest how you would automate the rollback process if a JAR was "published" with issues.
   • Propose a strategy for validating the published JAR in a real scenario (e.g., running integration tests against the artifact).

Time Frame:

This task should take about 2-4 hours to complete. We typically give 2 working days to complete the task.

Evaluation Criteria:

• Pipeline Design: The clarity and completeness of your pipeline design, ensuring it covers all necessary steps.
• Workflow Configuration: The accuracy and quality of your GitHub Actions workflow, including how well it integrates with Gradle.
• Problem-Solving: Your ability to address potential challenges and propose solutions for reliable and efficient JAR handling.
• Bonus Solutions: Creativity in proposing solutions for rollback automation and artifact validation.