The Java Function Buildpack is a Cloud Native Buildpack V3 that provides the riff Java Function Invoker to functions.
This buildpack is designed to work in collaboration with other buildpacks, which are tailored to support (and know how to build / run) languages supported by riff.
In Plain English
In a nutshell, when combined with the other buildpacks present in the riff builder what this means (and especially when dealing with the riff CLI which takes care of the creation of the
riff.toml file for you):
- The presence of a
build.gradlefile will result in the compilation and execution of a java function, thanks to the java invoker
--handlerflag is optional in certain cases, as documented by the java invoker
- Ambiguity in the detection process will result in a build failure
- The presence of the
--invokerflag will entirely bypass the detection mechanism and force a given language/invoker
Detailed Buildpack Behavior
Detection passes if
- the build plan already contains a
jvm-applicationkey (typically because a JVM based application was detected by the java buildpack)
If detection passes, the buildpack will contribute an
openjdk-jre key with
launch metadata to instruct
openjdk-buildpack to provide a JRE. It will also add a
riff-invoker-java key and
metadata extracted from the riff metadata.
If several languages are detected simultaneously, the detect phase errors out.
override key in
riff.toml can be used to bypass detection and force the use of a particular invoker.
If a java build has been detected
- Contributes the riff Java Invoker to a launch layer, set as the main java entry point with
function.uri = <build-directory>?handler=<handler>set as an environment variable.
The function behavior is exposed via standard buildpack process types:
How to Build
You can build the buildpack by running
This will package (with pre-downloaded cache layers) the buildpack in the
artifactory/io/projectriff/java/io.projectriff.java/latest directory. That can be used as a
uri in a
file of a builder (see https://github.com/projectriff/builder)
This buildpack is released under version 2.0 of the Apache License.