Online presentation given at the Clojure NYC meetup in July 2020.
and GraalVM; taking Clojure to new placesMichiel Borkent@borkdude2020-07-11
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• CLI tools with instant startup! (< 10ms)• clj-kondo: a linter for Clojure that sparks joy• jet: convert between JSON, EDN and Transit• No eval: dynamic classloader not supported!+
DSL -> scripting• Added a query DSL to jet, a GraalVM CLI: $ jet --query '(map :id)' <<< '[{:id 1} {:id 2}]' [1 2]• Extend this DSL to significant subset of Clojure?
• Native Clojure scripting tool, single binary, no JVM• Can be used to replace “the grey areas” of bash• Installable via script, brew (macOS, linux), aur (linux), scoop(Windows)$ time bb '(+ 1 2 3)' 6 0.00s user 0.00s system 67% cpu 0.013 total
CLJ scriptingRuntime Impl Startup* Interop Windows Execution Threadsclojure JVM Java ~1048ms + + Compiled +planck JSCore CLJS / JS ~ 728ms + - Compiled -joker Native Go ~7ms - + Interpreted -babashka Native GraalVM ~10ms + + Interpreted +*) measured with multitime -n10 -e '(+ 1 2 3)' on Ubuntu Bionic with Intel i7-3770K CPU @ 3.50GHz
Babashka goals• Fast starting Clojure scripting alternative for JVM Clojure• Easy installation: README ⟶ grab binary ⟶ run within seconds• Familiar: targeted at JVM clojure users• Cross-platform: #{linux, macOS, Windows}• Interop with commonly used classes (System, File, java.time.*, java.nio.*)• Multi-threading support (pmap, future, ...)• Batteries included (tools.cli, cheshire, ...) + external libraries + pods
Babashka non-goals• Performance• Long running performance intensive processes: use the JVM• Provide a mixed Clojure/Bash DSL (rather: be compatible with JVM Clojure)• Replace existing shells like Bash (rather: play well with them)
Shell interaction$ ls | bb -i '(filter #(-> % io/file .isDirectory) *input*)'("doc" "examples" "logo" ...)
Predefine functions$ export BABASHKA_PRELOADS="(defn is-dir? [f] (-> f io/file .isDirectory))" $ ls | bb -i '(filter is-dir? *input*)'("doc" "examples" "logo" ...)
Scripts$ pst.clj 04:58#!/usr/bin/env bb(def now (java.time.ZonedDateTime/now))(def LA-timezone (java.time.ZoneId/of "America/Los_Angeles"))(def LA-time (.withZoneSameInstant now LA-timezone))(def pattern (java.time.format.DateTimeFormatter/ofPattern "HH:mm"))(println (.format LA-time pattern))
Cross platform!
Included libs / namespaces• clojure.{core, edn, java.shell, java.io, pprint, set, string, test, walk, zip}• clojure.tools.cli• clojure.core.async• clojure.data.csv• cheshire.core (JSON)• clojure.xml• cognitect.transit• clj-yaml• babashka.curl
Compatibility with JVM• No deftype, definterface, reify (defrecord, defprotocoladded recently)• Code that does not use these constructs often works• Possible to load library code using existing mechanisms:classpath
Classpath;; spec.clj (require '[spartan.spec :as s]) (s/explain (s/cat :x int? :y keyword?) [1 #{:foo}])$ export BABASHKA_CLASSPATH=$(clojure -Spath ...)$ bb spec.clj #{:foo} - failed: keyword? in: [1] at: [:y]
Selection of compatible libs• spartan.spec: clojure.spec.alpha (1) for bb• clj-http-lite: lighter fork of cli-http-lite• medley: "missing" clojure utility functions • regal: create regular expressions from EDN/hiccup• camel-snake-kebab: word case conversions• aero: library for explicit, intentful configuration.• nubank/docopt: docopt in Clojure
$ clojure
$ deps.clj$ deps.clj -Sdeps ...C:\>deps.clj -Sdeps ...
Decomplecting babashkaLibraries coming out of babashka:• edamame: EDN/Clojure parser • sci: a Small Clojure Interpreter
edamame(def parsed (edamame/parse-string "#(+ 1 2 %)" {:fn true}));;=> (fn* [%1] (+ 1 2 %1))(meta parsed);;=> {:row 1, :col 1, :end-row 1, :end-col 11}- EDN/code parser- GraalVM compatible (no eval!)- location metadata- opt-in code-like features
Small Clojure Interpreter(def f (sci/eval-string "#(+ 1 2 %)"))(f 1);;=> 4- Clojure interpreter- Works on JVM / GraalVM / JS- Sandboxing - Works in CLJS advanced compiled apps - Also available on NPM
Sci from JavaScripthttps://observablehq.com/@jeroenvandijk/untitled/5$ npm install @borkdude/sci $ node > const { evalString, toJS } = require('@borkdude/sci'); > x = evalString("(assoc {:a 1} :b 2)") > toJS(x){ a: 1, b: 2 }
Malli: serializable schemas(def my-schema[:and[:map[:x int?][:y int?]][:fn '(fn [{:keys [x y]}] (> x y))]])(m/validate my-schema {:x 1, :y 0}); => true(m/validate my-schema {:x 1, :y 2}); => false
Function CLI args$ jet --from json --keywordize '(comp keyword str/upper-case)' \ <<< '{"a": 1}'{:A 1}
clj-kondo hooks• The problem:• Clj-kondo doesn't recognize syntax of user-defined macros• Existing solutions:• Add built-in support• :lint-as - only adequate for identical syntax• :unresolved-symbol - works for suppressing, but alsosuppresses useful information
clj-kondo hooks(ns mylib)(defmacro with-bound [binding-vector & body] ,,,)
clj-kondo hooks
clj-kondo hooks(hooks.with-bound/with-bound '(my-lib/with-bound [a 1 ...] ...))) => (let [a 1] {:with-bound/setting true} (inc 1))
Sci: adding libs(require '[cheshire.core :as json]) (def sci-opts {:namespaces {'cheshire.core {'generate-string json/generate-string}}}) (sci/eval-string"(require '[cheshire.core :as json])(json/generate-string {:a 1})"sci-opts) ;;=> "{\"a\":1}"
Projects using sci• borkdude/babashka• borkdude/clj-kondo (Clojure linter)• borkdude/jet (JSON, EDN, Transitconversion)• epiccastle/spire (Ansible in Clojure)• metosin/malli (serializable schemas)• retrogradeorbit/bootleg (static HTMLgeneration)• chlorine (Atom Clojure plugin)• dundalek/closh (Clojure shellreplacement, mixed Clojure/Bash DSL)• liquidz/dad (config management, e.g.complex install scripts)• alekcz/pcp (Clojure PHP replacement)• theiceshelf/firn (Org-mode static sitegenerator)
Bootleg: static site CLI
nREPL
Babashka podsProblems:• Including more libs into bb will cause GraalVM to takemore RAM, can't build on free CI anymore• Including more libs makes binary grow, while not alllibraries are useful to everyone• How to access functionality from other platforms usefulfor scripting (Rust, Go, Python)?
• Initial solutions:• Feature flags (PostgreSQL, HyperSQL, ...). Stillsupported.• Access native libraries (hard, brittle, too static)Babashka pods
• Standalone CLIs that can act as libraries to babashka• Can be built in Clojure + GraalVM or any other language(Rust, Python)• Architecture similar to nREPL• Uses bencode and (JSON or EDN) for RPCBabashka pods
• babashka-sql-pods (PostgreSQL, HyperSQL)• pod-babashka-etaoin (browser automation)• bootleg (HTML generation)• pod-babashka-filewatcher (implemented in Rust)• pod-babashka-parcera (whitespace preserving Clojureparser)• pod-lispyclouds-dockerBabashka pods
Filewatcher pod (Rust)
PostgreSQL pod (clojure)
Future• Babashka• book.babashka.org • bb.deps.edn / .babashka/config.edn• clojure.spec integration• Datomic client (optional via feature flag) • Sci• clojure.datafy• Smaller JS bundle by configuration• More control over duration / interrupts
Clojure + GraalVM• CLJ-1472: issue with GraalVM and locking macro• Solved in 1.10.2-alpha1 (thanks Rich and Alex!)• https://github.com/lread/clj-graal-docs• https://github.com/BrunoBonacci/graalvm-clojure/
Companies using babashka / sciGithub #254Add your company to the list:
ConclusionClojure might not be the best language for everything, likescripting Clojure is the best language for scripting.
Thanks to sponsors• Sponsors:• Github sponsors• OpenCollective• Ko-fi• Patreon
Thank you!https://github.com/borkdude/babashka https://github.com/borkdude/sciAnd the Small Clojure Interpreter