Coding Agent Instructions

Scope

This repository builds a custom Jenkins controller image with extra tooling for CI/CD workflows.

Structure Rules

• Keep responsibilities separated by file:
  • Dockerfile: base image, pinned tool/runtime versions, package and binary installation
  • jenkins.sh: container entrypoint and Jenkins JVM startup behavior
  • jenkins-support: shared shell helpers (copy/install/retry/version helpers)
  • install-plugins.sh: plugin download + dependency resolution logic
• Do not mix runtime behavior changes into Dockerfile when they belong in jenkins.sh or helper scripts.

Version Update Workflow

When updating image/tool versions, change all related items in one patch:

1. Base JDK image tag in Dockerfile.
2. Jenkins WAR pins:
   • JENKINS_VERSION
   • JENKINS_SHA from ${JENKINS_URL}.sha256
3. Tool pins (HELM_VERSION, TERRAFORM_VERSION, TINI_VERSION) and any matching download URLs.
4. Keep checksum/signature verification in place for downloaded artifacts.

Binary Install Standards

• Prefer pinned versions over implicit latest.
• Verify downloaded binaries with checksum or signature.
• Keep installs non-interactive and suitable for Docker build context.

Documentation

• Update README.md whenever behavior, defaults, or required configuration changes.