Integrate Jib for OCI image building #36

New Issue

2026-01-03T23:45:07Z

KofTwentyTwo commented

2026-01-03 23:45:07 +00:00

(Migrated from github.com)

Part of #13

User Story

As a developer, I want qctl to build OCI container images using Jib so that I can package my application without requiring Docker to be installed.

Design

Why Jib?

No Docker daemon required (builds directly to registry or tarball)
Fast incremental builds (separates dependencies from application)
Reproducible builds (deterministic layer ordering)
Native Java integration (Maven/Gradle plugins or Core API)

Integration Approach

Use Jib Core API (not Maven plugin) for flexibility:

Jib.from("eclipse-temurin:21-jre")
   .addLayer(List.of(dependencyJars), "/app/libs")
   .addLayer(List.of(applicationJar), "/app")
   .setEntrypoint("java", "-jar", "/app/application.jar")
   .containerize(Containerizer.to(RegistryImage.named("registry/app:v1")));

Configuration

Project-level qrun.yaml:

package:
  baseImage: eclipse-temurin:21-jre
  ports:
    - 8080
  jvmFlags:
    - "-Xmx512m"
    - "-XX:+UseG1GC"
  mainClass: com.example.MyApp  # Auto-detected if not specified
  user: 1000:1000

Build Modes

Mode	Command	Output
Local tarball	`qrun package --local`	`target/app.tar`
Docker daemon	`qrun package --docker`	Local Docker image
Registry	`qrun package --registry`	Push to configured registry

Files to Create/Modify

File	Action	Description
`qctl-qrun/pom.xml`	Modify	Add jib-core dependency
`JibBuilder.java`	Create	Wraps Jib Core API
`PackageConfig.java`	Create	Configuration model for packaging
`QrunConfig.java`	Create	Parses qrun.yaml
`PackageCommand.java`	Modify	Wire up JibBuilder

Implementation Tasks

Add com.google.cloud.tools:jib-core:0.27.0 dependency
Create PackageConfig record for build configuration
Create QrunConfig for parsing qrun.yaml
Implement JibBuilder wrapper class
Auto-detect main class from JAR manifest
Support custom base images via config
Support custom JVM flags
Support port exposure configuration
Support user/group configuration
Implement --local mode (tarball output)
Implement --docker mode (Docker daemon)
Add progress output during build
Add unit tests with mock registry

Acceptance Criteria

qrun package builds OCI image without Docker
Base image configurable via qrun.yaml
JVM flags applied correctly
Ports exposed in image metadata
Main class auto-detected or configurable
Build completes in under 30s for incremental
Works on Linux, macOS, and Windows

Part of #13 ## User Story As a **developer**, I want qctl to build OCI container images using Jib so that I can package my application without requiring Docker to be installed. ## Design ### Why Jib? - No Docker daemon required (builds directly to registry or tarball) - Fast incremental builds (separates dependencies from application) - Reproducible builds (deterministic layer ordering) - Native Java integration (Maven/Gradle plugins or Core API) ### Integration Approach Use Jib Core API (not Maven plugin) for flexibility: ```java Jib.from("eclipse-temurin:21-jre") .addLayer(List.of(dependencyJars), "/app/libs") .addLayer(List.of(applicationJar), "/app") .setEntrypoint("java", "-jar", "/app/application.jar") .containerize(Containerizer.to(RegistryImage.named("registry/app:v1"))); ``` ### Configuration Project-level `qrun.yaml`: ```yaml package: baseImage: eclipse-temurin:21-jre ports: - 8080 jvmFlags: - "-Xmx512m" - "-XX:+UseG1GC" mainClass: com.example.MyApp # Auto-detected if not specified user: 1000:1000 ``` ### Build Modes | Mode | Command | Output | |------|---------|--------| | Local tarball | `qrun package --local` | `target/app.tar` | | Docker daemon | `qrun package --docker` | Local Docker image | | Registry | `qrun package --registry` | Push to configured registry | ## Files to Create/Modify | File | Action | Description | |------|--------|-------------| | `qctl-qrun/pom.xml` | Modify | Add jib-core dependency | | `JibBuilder.java` | Create | Wraps Jib Core API | | `PackageConfig.java` | Create | Configuration model for packaging | | `QrunConfig.java` | Create | Parses qrun.yaml | | `PackageCommand.java` | Modify | Wire up JibBuilder | ## Implementation Tasks - [ ] Add `com.google.cloud.tools:jib-core:0.27.0` dependency - [ ] Create `PackageConfig` record for build configuration - [ ] Create `QrunConfig` for parsing `qrun.yaml` - [ ] Implement `JibBuilder` wrapper class - [ ] Auto-detect main class from JAR manifest - [ ] Support custom base images via config - [ ] Support custom JVM flags - [ ] Support port exposure configuration - [ ] Support user/group configuration - [ ] Implement `--local` mode (tarball output) - [ ] Implement `--docker` mode (Docker daemon) - [ ] Add progress output during build - [ ] Add unit tests with mock registry ## Acceptance Criteria - [ ] `qrun package` builds OCI image without Docker - [ ] Base image configurable via `qrun.yaml` - [ ] JVM flags applied correctly - [ ] Ports exposed in image metadata - [ ] Main class auto-detected or configurable - [ ] Build completes in under 30s for incremental - [ ] Works on Linux, macOS, and Windows

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Reference: QRun-IO/qctl#36