Babashka tasks (at London Clojurians July 2021)

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Tasks Michiel Borkent @borkdude 2021-07-20

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• Native Clojure scripting tool, single binary, no JVM • Developed since August 2019 (2000+ stars, 68 contributors) • Can be used to replace “the grey areas” of bash • Installable via script, brew (macOS, linux), aur (linux), scoop (Windows) $ time bb -e '(+ 1 2 3)'  6  0.00s user 0.00s system 67% cpu 0.013 total

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Make, just, etc. • Complex project-speciﬁc CLI invocations • Remember • Shortcuts • Discoverability • Fast startup • Only rebuild when necessary (make) • Clojure...?

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Babashka tasks $ bb run clean  # or  $ bb clean

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Use any bb compatible lib $ bb clean

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Arbitrary (EDN compatible) expressions $ bb clean  Removing target folder.

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bb run options: --parallel $ bb run --parallel d  d: #inst "2021-05-08T14:14:56.322-00:00"  a: #inst "2021-05-08T14:14:56.357-00:00"  b: #inst "2021-05-08T14:14:56.360-00:00"  c: #inst "2021-05-08T14:15:01.366-00:00"  "Elapsed time: 5023.894512 msecs"

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bb run options: --prn

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Hooks: :init

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Hooks: :enter, :leave

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Command line args • Just use *command-line-args*, bb leaves it unprocessed. • To pass args from a task to another task, use binding + run

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Task-local options

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Discoverability

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Tasks API: run, clojure, shell

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Tasks API: run, clojure, shell

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Tasks API: run, clojure, shell

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Tasks API: run, clojure, shell

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Dependencies

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Rebuild when necessary

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Dependencies (parallel) $ bb coffeep (1168ms)  $ bb run --parallel coffeep (654ms)

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Dependencies (parallel)

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Invoking a main function

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Real examples • clj-kondo.lsp • bb.edn at Doctor Evidence • rewrite-clj • More links in docs

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Docs https://book.babashka.org/#tasks

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Babashka tasks • Complex project-speciﬁc CLI invocations • Remember • Shortcuts • Discoverability • Fast startup • Only rebuild when necessary • Clojure!

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Thanks to sponsors! https://opencollective.com/babashka/contribute https://github.com/sponsors/borkdude

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Thanks Michiel Borkent @borkdude 2021-07-20