lesson #32

Author: astynax

otus-32/README.org

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+#+TITLE: Скрипты на Clojure, Babashka runtime
+
+#+begin_quote
+Познакомимся с проектом babashka для написания скриптов на Clojure;
+Научимся создавать command line interface для своих скриптов,
+автоматизировать рутинные задачи с использованием babashka tasks.
+#+end_quote
+
+* [[https://babashka.org/][Babashka]]
+
+Диалект Clojure, имеющий [[https://github.com/babashka/babashka#differences-with-clojure][некоторые отличия]] от оригинала.
+
+** Основы
+
+#+BEGIN_SRC shell :results verbatim
+
+echo "Hello" | bb -e '(str *input* ", World!")'
+
+bb '(+ 1 2 3)'
+
+#+END_SRC
+
+#+BEGIN_SRC shell :results verbatim
+
+echo "{:a 42 :b 100}" | \
+    bb -IO -e '(let [[{:keys [a b]} & _] *input*] {:result (+ a b)})'
+
+#+END_SRC
+
+** Вызов внешних команд
+
+#+BEGIN_SRC clojure
+
+(println (:out (shell/sh "echo" "123")))
+
+#+END_SRC
+
+#+BEGIN_SRC clojure
+
+(prn (shell/sh "echo" "123"))
+
+#+END_SRC
+
+#+BEGIN_SRC clojure :backend babashka
+
+(println '((1 2 3) (4 5 6)))
+
+#+END_SRC
+
+** CLI args ([[https://github.com/babashka/cli][babashka.cli]])
+
+#+BEGIN_SRC clojure
+
+(require '[babashka.cli :as cli])
+
+(cli/parse-args ["--output" "foo.txt" "--" "bar"])
+
+(cli/parse-opts ["--port=8080"] {:coerce {:port :int}})
+
+(cli/parse-args ["--verbose"])
+
+#+END_SRC
+
+** Задачи и [[file:bb.edn][bb.edn]]
+
+Список задач:
+
+#+BEGIN_SRC shell :results verbatim
+
+bb tasks
+
+#+END_SRC
+
+Выполнение задачи:
+
+#+BEGIN_SRC shell
+
+bb run grep-me
+
+#+END_SRC

otus-32/bb.edn

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+{:tasks
+ {hi
+  {:doc "Greets you"
+   :task (shell "echo 123")}
+
+  hihi
+  (do (run 'hi)
+      (run 'hi))
+
+  grep-me
+  (-> (shell {:out :string} "echo -n '123\n456\n")
+      (shell "grep 5"))}}

otus-32/script.clj

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+#!/usr/bin/env bb -I
+
+(defn sum-a-and-b []
+  (let [[{:keys [a b]} & _] *input*]
+    {:result (+ a b)}))
+
+(prn (sum-a-and-b))