Implement --add-bootstrap-header

README.md

@@ -34,6 +34,7 @@ Taken all these features together, `kscript` provides an easy-to-use, very flexi
 - [Treat yourself a REPL with `--interactive`](#treat-yourself-a-repl-with---interactive)
 - [Boostrap IDEA from a `kscript`let](#boostrap-idea-from-a-kscriptlet)
 - [Deploy scripts as standalone binaries](#deploy-scripts-as-standalone-binaries)
+- [Embed kscript installer within a script](#embed-kscript-installer-within-a-script)
 - [FAQ](#faq)
 - [Support](#support)
 - [How to contribute?](#how-to-contribute)
@@ -427,6 +428,22 @@ The created binary will contain a compiled copy of the script, as well as all de
 
 Just `java` is required to run these binaries.
 
+
+Embed kscript installer within your script
+--------------------------------------
+
+ To make a script automatically [install kscript](#installation) and its dependencies on first run if necessary, run:
+
+ ```bash
+kscript --add-bootstrap-header some_script.kts
+```
+
+Now `some_script.kts` can be shared and run directly on any other machine that has `bash`, without having to go through the [Installation](#installation) steps first.
+
+Note that unlike the [`--package` option](#deploy-scripts-as-standalone-binaries) this doesn't produce a separate file, allowing the distributed script to be read and modified(including with [`kscript --idea`](#boostrap-idea-from-a-kscriptlet)) similar to what you might expect with bash/python/ruby scripts.
+On the other hand this doesn't embed dependencies within the script("fat jar"), so internet connection may be required on its first run.
+
+
 FAQ
 ---
 

src/main/kotlin/kscript/app/Kscript.kt

@@ -2,6 +2,7 @@ package kscript.app
 
 import kscript.app.ShellUtils.requireInPath
 import org.docopt.DocOptWrapper
+import org.intellij.lang.annotations.Language
 import java.io.BufferedReader
 import java.io.File
 import java.io.FileInputStream
@@ -43,6 +44,7 @@ Options:
  --idea                  Open script in temporary Intellij session
  -s --silent             Suppress status logging to stderr
  --package               Package script and dependencies into self-dependent binary
+ --add-bootstrap-header  Prepend bash header that installs kscript if necessary
 
 
 Copyright : 2017 Holger Brandl
@@ -59,6 +61,18 @@ val KSCRIPT_CACHE_DIR = System.getenv("KSCRIPT_CACHE_DIR")?.let { File(it) }
 // use lazy here prevent empty dirs for regular scripts https://github.com/holgerbrandl/kscript/issues/130
 val SCRIPT_TEMP_DIR by lazy { createTempDir() }
 
+@Language("sh")
+private val BOOTSTRAP_HEADER = """
+    #!/bin/bash
+
+    //usr/bin/env echo '
+    /**** BOOTSTRAP kscript ****\'>/dev/null
+    command -v kscript >/dev/null 2>&1 || curl -L "https://git.io/fpVLG" | bash 1>&2
+    exec kscript $0 "$@"
+    \*** IMPORTANT: Any code including imports and annotations must come after this line ***/
+
+    """.trimIndent().lines()
+
 
 fun main(args: Array<String>) {
     // skip org.docopt for version and help to allow for lazy version-check
@@ -124,6 +138,33 @@ fun main(args: Array<String>) {
     val enableSupportApi = docopt.getBoolean("text")
     val (rawScript, includeContext) = prepareScript(scriptResource)
 
+    if (docopt.getBoolean("add-bootstrap-header")) {
+        errorIf(!rawScript.canWrite()) {
+            "Script file not writable: $rawScript"
+        }
+        errorIf(rawScript.parentFile == SCRIPT_TEMP_DIR) {
+            "Temporary script file detected: $rawScript, created from $scriptResource"
+        }
+        val scriptLines = rawScript.readLines().dropWhile {
+            it.startsWith("#!/") && it != "#!/bin/bash"
+        }
+
+        errorIf(scriptLines.getOrNull(0) == BOOTSTRAP_HEADER[0]
+                && scriptLines.any { "command -v kscript >/dev/null 2>&1 || " in it }) {
+            val lastHeaderLine = BOOTSTRAP_HEADER.findLast { it.isNotBlank() }!!
+            val preexistingHeader =
+                    scriptLines.dropLastWhile { it != lastHeaderLine }.joinToString("\n")
+            "Bootstrap header already detected:\n\n$preexistingHeader\n\n" +
+                    "You can remove it to force the re-generation"
+        }
+
+        rawScript.writeText((BOOTSTRAP_HEADER + scriptLines).joinToString("\n"))
+
+        if (loggingEnabled) {
+            info("$rawScript updated")
+        }
+        quit(0)
+    }
 
     // post process script (text-processing mode, custom dsl preamble, resolve includes)
     // and finally resolve all includes (see https://github.com/holgerbrandl/kscript/issues/34)

test/resources/echo_stdin_args.kts

@@ -0,0 +1,6 @@
+#!/usr/bin/env kscript
+
+if (System.console() == null) {
+    print(generateSequence(::readLine).joinToString("\n") + " | ")
+}
+println("script ${args.toList().joinToString(" ")}")

test/test_suite.sh

@@ -278,3 +278,30 @@ assert_end misc
 assert_raises "./gradlew test"
 
 assert_end junit_tests
+
+
+########################################################################################################################
+##  bootstrap header
+
+f=/tmp/echo_stdin_args.kts
+cp ${KSCRIPT_HOME}/test/resources/echo_stdin_args.kts $f
+
+# ensure script works as is
+assert 'echo stdin | '$f' --foo bar' "stdin | script --foo bar"
+
+# add bootstrap header
+assert 'kscript --add-bootstrap-header '$f ''
+
+# ensure adding it again raises an error
+assert_raises 'kscript --add-bootstrap-header '$f 1
+
+# ensure scripts works with header, including stdin
+assert 'echo stdin | '$f' --foo bar' "stdin | script --foo bar"
+
+# ensure scripts works with header invoked with explicit `kscript`
+assert 'echo stdin | kscript '$f' --foo bar' "stdin | script --foo bar"
+
+
+rm $f
+
+assert_end bootstrap_header