Building native CLI tools with Clojure on GraalVM

A long time ago in a galaxy far, far away... Clojure had garnered the reputation of being a heavy weight tool ideal only for server deployments on the JVM. Added together with its dynamic nature, full native compilation needed for fast and portable CLI tools seemed a fantasy. Until now...

Learn about using the GraalVM to build such tools while still using the best language ever.

Transcript

1. Building native CLI tools with Clojure on GraalVM Rahul De @lispyclouds
2. About me (❤ FOSS) (" Diversity)
 (❤ Sustainable Living) ( Vegan Food) (constantly [:❤ :Clojure]) Backend and Infrastructure Developer Compilers, VMs and High Performance https://github.com/lispyclouds https://twitter.com/lispyclouds
3. https://www.youtube.com/watch?v=topKYJgv6qA
4. CLI tools and native compilation Instant startup time ⚡ Easy and lightweight installation Short lived commands & Portable and easy distributions without too much system requirements Low resource consumption Simple, obvious naming convention and intuitive CLI arguments
5. Instant startup is the Holy Grail?
6. Clojure and the JVM Clojure is dynamic JVM reflection The JVM byte code itself is dynamic JIT and the design of the JVM
8. Alternatives?
9. Rust Immutable by default with functional features Super fast Fully AOT compiled GC less automatic memory management Safe Low resource consumption Slow compile times Less mature libs
10. Haskell For me, the only other thing as cool as Clojure! Fast compiled binaries Very very safe Mature Slow compile times Practically zero dev tooling, slow dev iterations High memory consumption at times
11. Python Very mature Pre installed in most *nix systems Dynamic Vast and mature tooling and libs Imperativeness is idiomatic Concurrency is hard Package management is hard Unpredictable resource consumption
12. Go Super fast compile times Ubiquitous in CLI world Easy deployment Vast stdlib Imperative, difficult to write FP Not a productive language IMO for large projects
13. C/C++ Let’s not talk about this.
14. But none of them are Clojure
15. ClojureScript Runs on Node.js (Lumo) or JavaScriptCore (Planck) Quick startup without JVM overhead Decent stdlib support from Node world Mature and robust libs missing from JVM world Poor parallelism High memory consumption Complex deployment and not available for archs other than AMDx64
16. – The Oracle (probably not the one you’re thinking of) “When all hope was lost, there came our savior.”
17. – This one
18. The one VM to rule them all? An umbrella project of various tools Works via the JVMCI since JDK 9 A JIT written in Java Natively available since JDK 10 Full Polyglot capabilities Truffle SDK Full native image generation with GC using SubstrateVM. (Great way to warm up your room) https://www.graalvm.org
19. ❤
20. Wendy: Bob’s reference CLI and his SO Bob is a scalable, modular CI/CD platform (by your’s truly) 
 https://github.com/bob-cd/bob exposed via REST. Wendy should be able to: Make HTTP calls Parse JSON Parse TOML build configuration Provide a full CLI to Bob via intuitive command line args Verify the build and plan the execution order (magical to write in Clojure) Stream build status, info, logs and artifacts from Bob (think Docker CLI) https://github.com/bob-cd/wendy Was in Python 3 untill the fateful commit aba8aad
21. Building Wendy Standard Tool Wendy’s Choice HTTP Calls clj-http clj-http-lite JSON Parsing cheshire cheshire TOML Parsing clj-toml Night-Config
 (really cool lib!) CLI args parsing • tools.cli • clj-matic argparse4j
22. Demo • Dev setup 
 (including clj-kondo) • Running • Testing and distribution
23. Resources • https://www.graalvm.org/ • https://github.com/bob-cd/wendy • https://github.com/taylorwood/ clj.native-image • https://www.graalvm.org/docs/ reference-manual/aot-compilation/ • https://www.graalvm.org/docs/ reference-manual/polyglot/
24. Thank you! Questions?