jayfu

Learn how to make a native Clojure CLI with GraalVM native-image and SCI!

This example is set up around an example CLI, jayfu, that reads JSON from stdin and transforms it using a function which is dynamically evaluated:

$ echo '{"a": {"b": 2}}' | ./jayfu -f '#(-> % :a :b)' -k keyword
2

See this talk which guides you through this project.

Prerequisites

• Download GraalVM. Just download it to your Downloads folder and unzip the archive. No further installation required. This tutorial is based on version 21.1.0 JDK11.

• Set the GRAALVM_HOME environment variable. E.g.:

  export GRAALVM_HOME=/Users/borkdude/Downloads/graalvm-ce-java11-21.1.0/Contents/Home

• To run with Clojure or Java, you will need to have a Java 8 or 11 installation available. You can also use the downloaded GraalVM for this.

• Install babashka (0.4.1 or higher).

Windows

Always use cmd.exe for executing GraalVM compilation, do not use PowerShell.

On Windows, install Visual Studio 2017 or 2019 and in cmd.exe load:

"C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Auxiliary\Build\vcvars64.bat"

This will set the right environment variables for GraalVM.

After this you should be able to run bb native-image.

Tasks

To see all available tasks in this project, run bb tasks:

$ bb tasks
The following tasks are available:

run-main     Run main
uberjar      Builds uberjar
run-uber     Run uberjar
graalvm      Checks GRAALVM_HOME env var
native-image Builds native image

Run

To run this example using Clojure, run:

$ bb run-main --help
Usage:
  -f, --func FUNCTION  identity  The function applied to JSON from stdin
  -k, --key-fn KEY-FN  identity  The function applied to keywords
  -h, --help

$ echo '{"a": {"b": 2}}' | bb run-main -f '#(-> % :a :b)' -k keyword
2

Build

To build the native image, run:

$ bb native-image

This should produce a binary called jayfu:

$ echo '{"a": {"b": 2}}' | ./jayfu -f '#(-> % :a :b)' -k keyword
2

Talk

See this talk which guides you through this project.

Tutorial

Coming soon.

License

Copyright © 2021 Michiel Borkent

Distributed under the EPL License. See LICENSE.