Kommand

Kotlin Native library for create sub-process and redirect their I/O.

v2.3.0

Rust is an excellent language that takes into account both performance and engineering.

In version 1.x, we use the following API to provide the function of creating child processes

• fork of [POSIX api]
• CreateChildProcess of [win32 api]
• java.lang.ProcessBuilder of JVM

In version 2.x, we use the Rust standard library to provide the function of creating child processes.

• std::process::Command of Rust
• java.lang.ProcessBuilder of JVM

It will bring

• More unified API
• Easier to use API
• Performance is still excellent
• Easier to maintain
• Code structure is clearer

Supported Platforms

• x86_64-apple-darwin
• aarch64-apple-darwin
• x86_64-unknown-linux-gnu
• aarch64-unknown-linux-gnu
• x86_64-pc-windows-gnu (mingw-w64)
• jvm

Dependent

• Rust Standard Library 1.83.0
• Kotlin Multiplatform 2.1.0

Usage

Dependency

build.gradle.kts:

// ……
repositories {
    mavenCentral()
}
// ……

dependencies {
    // should replace with the latest version
    implementation("com.kgit2:kommand:2.x")
}

Quick Start

Inherit Standard I/O

kommand/kommand-examples/example1/src/commonMain/kotlin/com/kgit2/kommand/Main.kt

Lines 1 to 12 in af7c721

	package com.kgit2.kommand
	import com.kgit2.kommand.process.Command
	import com.kgit2.kommand.process.Stdio
	fun main() {
	Command("ping")
	.args(listOf("-c", "5", "localhost"))
	.stdout(Stdio.Inherit)
	.spawn()
	.wait()
	}

Piped I/O

kommand/kommand-examples/example2/src/commonMain/kotlin/com/kgit2/kommand/Main.kt

Lines 1 to 15 in af7c721

	package com.kgit2.kommand
	import com.kgit2.kommand.process.Command
	import com.kgit2.kommand.process.Stdio
	fun main() {
	val child = Command("ping")
	.args(listOf("-c", "5", "localhost"))
	.stdout(Stdio.Pipe)
	.spawn()
	child.bufferedStdout()?.lines()?.forEach { line ->
	println(line)
	}
	child.wait()
	}

Null I/O

kommand/kommand-examples/example3/src/commonMain/kotlin/com/kgit2/kommand/Main.kt

Lines 1 to 12 in af7c721

	package com.kgit2.kommand
	import com.kgit2.kommand.process.Command
	import com.kgit2.kommand.process.Stdio
	fun main() {
	Command("echo")
	.arg("nothing")
	.stdout(Stdio.Null)
	.spawn()
	.wait()
	}

Timeout Detection

kommand/kommand-examples/timeout/src/appleMain/kotlin/com/kgit2/kommand/Main.kt

Lines 1 to 60 in 7367c60

	package com.kgit2.kommand
	import com.kgit2.kommand.process.Command
	import kotlinx.coroutines.Dispatchers
	import kotlinx.coroutines.IO
	import kotlinx.coroutines.async
	import kotlinx.coroutines.runBlocking
	import kotlinx.coroutines.withTimeout
	import kotlinx.datetime.Clock
	fun main() = runBlocking(Dispatchers.Default) {
	// Sleep with regular
	val start = Clock.System.now()
	val status = Command("sleep").arg("5").status()
	println("status: $status elapsed: ${Clock.System.now() - start}")
	// Sleep with timeout detection and timeout determination
	val start2 = Clock.System.now()
	val child = Command("sleep").arg("5").spawn()
	val childJob = async(Dispatchers.IO) {
	runCatching {
	child.wait()
	}.onFailure {
	println("child result: $it")
	}.getOrNull()
	}
	runCatching {
	withTimeout(3000) {
	childJob.await()
	}
	}.onSuccess {
	println("status: $it elapsed: ${Clock.System.now() - start2}")
	}.onFailure {
	child.kill()
	println("status: $it elapsed: ${Clock.System.now() - start2}")
	}
	// Sleep with timeout detection and determination that it will not timeout
	val start3 = Clock.System.now()
	val child2 = Command("sleep").arg("2").spawn()
	val childJob2 = async(Dispatchers.IO) {
	runCatching {
	child2.wait()
	}.onFailure {
	println("child result: $it")
	}.getOrNull()
	}
	runCatching {
	withTimeout(3000) {
	childJob2.await()
	}
	}.onSuccess {
	println("status: $it elapsed: ${Clock.System.now() - start3}")
	}.onFailure {
	child2.kill()
	println("status: $it elapsed: ${Clock.System.now() - start3}")
	}
	Unit
	}

Full example check kommand-examples/timeout.

Dependency:

• required kotlinx-coroutines

Build by yourself

1. Dependencies

• rust toolchain - 1.83.0 (https://rustup.rs)
  • just (install with cargo install just)
• cross-compile toolchain
  • x86_64-apple-darwin
  • aarch64-apple-darwin
  • x86_64-unknown-linux-gnu
  • aarch64-unknown-linux-gnu
  • x86_64-pc-windows-gnu (mingw-w64)
• docker (optional)

Recommend build all platforms in macOS.

Kotlin Multiplatform gets the most complete support on macOS.

If you are using macOS, you can install the cross-compile toolchain with

just prepare

Otherwise, you need to install the cross-compile toolchain yourself.

2. Clone this repo

git clone https://github.com/kgit2/kommand.git

3. Build kommand-core

cd kommand-core
just all

4. Build kommand

./gradlew build

5. cross-platform test

Only linux support cross-platform test.

• install docker

Install Docker Engine

• test it

# for x86_64
just linuxX64Test
# for aarch64
just linuxArm64Test

Maintainers

@BppleMan.

@XJMiada.(Original Picture)

License

Apache2.0 © BppleMan

Credits

• 

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