Jib vs Source-to-Image

Jib builds Docker and OCI images for Java applications without a Docker daemon. It can be used as a Maven or Gradle plugin, a Java library, or a command-line interface, and runs on Linux, macOS, and Windows. Jib divides application contents into layers, allowing code changes to be rebuilt without rebuilding the whole image. It can push images to a container registry of the user's choice, uses an OpenJDK base image by default, and accepts a custom base image. The project says that rebuilding an image from the same contents produces the same image. It supports local build caches and multi-architecture builds, and the project says it works well with Google Cloud Build. Examples cover Spring Boot, Micronaut, multi-module projects, and Spark Java with a Java Agent. Jib is free and open source under Apache License, Version 2.0. The project is not an officially supported Google product; it directs usage questions to Stack Overflow and also links to GitHub issues and a FAQ.

Source-to-Image is a free, Apache-2.0 toolkit for building reproducible container images from source code. It places source in a builder image, lets that container prepare the application, and outputs a ready-to-run image. A documented workflow can build from a Git repository without a Dockerfile. Builder images may provide assemble and run scripts, plus optional scripts for saving artifacts and explaining usage. Compatible builders can reuse artifacts from an earlier output when incremental settings and scripts are supplied. A .s2iignore file filters source files and directories, while .s2i/environment defines build variables that also appear in the output image. S2I can use an OnBuild strategy with images containing Dockerfile ONBUILD instructions. Examples cover Docker, OpenShift, UBI, Ruby, and WildFly. It runs on Linux, macOS, and Windows, with Docker 1.6+ and Go 1.7.1+ listed as dependencies.