Support for Google Jib plugin - Docker daemon compatibility

[noahxp]

Problem Statement

AWS Finch currently doesn't support Google Jib's jibDockerBuild task, which is a widely-used tool in the Java ecosystem for containerizing Spring Boot applications. This limits Finch's effectiveness as a complete Docker Desktop
replacement.

Current Behavior

When running ./gradlew jibDockerBuild with Finch:
FAILURE: Build failed with an exception.

• What went wrong:
  Execution failed for task ':jibDockerBuild'.
  Build to Docker daemon failed, perhaps you should make sure Docker is installed and you have correct privileges to run it

Technical Background

• Google Jib uses the Docker Java API to communicate directly with the Docker daemon
• Shell aliases (alias docker=finch) don't affect Java applications that use Docker client libraries
• Jib expects a Docker daemon socket (typically /var/run/docker.sock) for local builds
• Finch architecture uses containerd + nerdctl in a Lima VM, without exposing a Docker daemon socket

Environment

• macOS: Darwin 24.6.0
• Finch version: v1.10.3
• Java: 21
• Gradle: 8.14.1
• Jib plugin: 3.4.5

Proposed Solutions

1. Docker API Compatibility Layer: Provide a Docker daemon-compatible API endpoint that translates Docker API calls to nerdctl/containerd operations
2. Socket Proxy: Expose a Docker-compatible socket that forwards requests to the containerd runtime
3. Documentation: Provide clear guidance on alternative workflows (e.g., using jibBuildTar + finch load)

Use Case

This affects Java developers who:

• Want to use Finch as a Docker Desktop replacement
• Use Gradle/Maven with Jib for container builds
• Need local container building for development workflows

Workaround

Currently, users must:

1. Use ./gradlew jibBuildTar to build a tar archive
2. Load with finch load < build/jib-image.tar
3. Or push directly to a registry with ./gradlew jib

However, this disrupts the standard development workflow and CI/CD pipelines expecting jibDockerBuild to work.

Related

This issue affects other tools that depend on Docker daemon API, making it a broader compatibility concern for Java containerization workflows.

[coderbirju]

Hi @noahxp

Thanks for your interest in finch!
For the following points

Jib expects a Docker daemon socket (typically /var/run/docker.sock) for local builds
Finch architecture uses containerd + nerdctl in a Lima VM, without exposing a Docker daemon socket

Finch currently also bundles the finch-daemon in its binaries, finch-daemon is a docker compatible container runtime engine just like the docker daemon.
Although finch uses containerd + nerdctl in a Lima VM, it also exposes a docker socket at var/run/finch.sock, since Jib expects a docker daemon socket you may be able to point it to var/run/finch.sock using the DOCKER_HOST env variable.

For Example:

finch vm init
export DOCKER_HOST=unix:///var/run/finch.sock
<-- execute your jib build command here -->

Do let us know if this works for you, there may be some features that are not yet supported in finch-dameon, we can add those based on customer feedback like yours

[noahxp]

Thanks for your response! Here's my testing results:

Setup:
I manually installed and started finch-daemon as mentioned in the documentation.

Test Results:
✅ Basic finch commands work fine:

finch version
finch ps
finch compose up

✅ Docker API connectivity works:
DOCKER_HOST=unix:///var/run/finch.sock docker version
DOCKER_HOST=unix:///var/run/finch.sock docker info

❌ Jib build fails:
DOCKER_HOST=unix:///var/run/finch.sock ./gradlew jibDockerBuild

Build to Docker daemon failed, perhaps you should make sure Docker is installed and you have correct
privileges to run it

Error Stack (key parts):
Caused by: org.gradle.api.GradleException: Build to Docker daemon failed, perhaps you should make sure Docker is
installed and you have correct privileges to run it
at com.google.cloud.tools.jib.gradle.BuildDockerTask.buildDocker(BuildDockerTask.java:103)
at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:103)
at org.gradle.internal.reflect.JavaMethod.invoke(JavaMethod.java:125)
at org.gradle.api.internal.project.taskfactory.StandardTaskAction.doExecute(StandardTaskAction.java:58)

[pendo324]

Hey @noahxp, are you running on Linux or macOS? If macOS, then the finch daemon path should be DOCKER_HOST=unix:///Applications/Finch/lima/data/finch/sock/finch.sock

The build failure looks interesting. You'd have to look at the logs for finch-daemon using sudo journalctl -xeu finch to see exactly what went wrong.

Currently, we're not planning to explicitly support the Google Jib plugin in finch-daemon, but we are accepting contributions in the https://github.com/runfinch/finch-daemon/ repository. Once you take a look at the logs, you can determine if there's an API error due to e.g. an API or API parameter that the finch-daemon does not yet support, or some other issue.

[coderbirju]

Apologies I misread you OS configuration and gave you the linux socket address

On MacOs we use lima for virtualization and the finch-daemon socket is accessible via this socket
/Applications/Finch/lima/data/finch/sock/finch.sock

• Ensure vm is running
• set DOCKER_HOST=unix:///Applications/Finch/lima/data/finch/sock/finch.sock
• Verify socket is accessible

~ DOCKER_HOST=unix:///Applications/Finch/lima/data/finch/sock/finch.sock docker version
Client: Docker Engine - Community
 Version:           28.3.3
 API version:       1.43 (downgraded from 1.51)
 Go version:        go1.24.5
 Git commit:        980b856816
 Built:             Wed Jul 16 10:32:48 2025
 OS/Arch:           darwin/arm64
 Context:           default

Server: Finch Daemon - v0.20.0
 containerd:
  Version:          v2.1.3
  GitCommit:        c787fb98911740dd3ff2d0e45ce88cdf01410486
 runc:
  Version:          1.3.0
  GitCommit:        v1.3.0-0-g4ca628d
 Engine:
  Version:          v0.20.0
  API version:      1.43 (minimum version 1.35)
  Go version:
  Git commit:       ef5d71ddf0a98f39f6ebcf0401b8706543c9f04e
  Built:
  OS/Arch:          Linux/aarch64
  Experimental:     false