在Swift中终止macOS命令行工具的子进程

Question

我正在快速编写一个macOS命令行工具来执行shell命令：

let process = Process()
process.launchPath = "/bin/sleep"
process.arguments = ["100"]
process.launch()
process.waitUntilExit()

但是，如果将中断（ CTRL-C ）或终止信号发送到我的程序，则这些shell命令不会终止，而只会继续执行它们。

如果我的程序意外终止，是否可以自动终止它们？

Answer 1

这是我们的工作，以便在使用两个管道子进程时对中断（ CTRL-C ）做出反应。

背后的思想 ：阻止waitUntilExit()调用替换为异步terminationHandler 。 无限循环dispatchMain()用于提供调度事件。 收到Interrupt信号后，我们在子进程上调用interrupt() 。

封装子流程启动和中断逻辑的示例类：

class AppTester: Builder {

   private var processes: [Process] = [] // Keeps references to launched processes.

   func test(completion: @escaping (Int32) -> Void) {

      let xcodebuildProcess = Process(executableName: "xcodebuild", arguments: ...)
      let xcprettyProcess = Process(executableName: "xcpretty", arguments: ...)

      // Organising pipe between processes. Like `xcodebuild ... | xcpretty` in shell
      let pipe = Pipe()
      xcodebuildProcess.standardOutput = pipe
      xcprettyProcess.standardInput = pipe

      // Assigning `terminationHandler` for needed subprocess.
      processes.append(xcodebuildProcess)
      xcodebuildProcess.terminationHandler = { process in
         completion(process.terminationStatus)
      }

      xcodebuildProcess.launch()
      xcprettyProcess.launch()
      // Note. We should not use blocking `waitUntilExit()` call.
   }

   func interrupt() {
      // Interrupting running processes (if any).
      processes.filter { $0.isRunning }.forEach { $0.interrupt() }
   }
}

用法（即main.swift ）：

let tester = AppTester(...)
tester.test(....) {
   if $0 == EXIT_SUCCESS {
      // Do some other work.
   } else {
      exit($0)
   }
}

// Making Interrupt signal listener.
let source = DispatchSource.makeSignalSource(signal: SIGINT)
source.setEventHandler {
   tester.interrupt() // Will interrupt running processes (if any).
   exit(SIGINT)
}
source.resume()
dispatchMain() // Starting dispatch loop. This function never returns.

shell中的示例输出：

...
▸ Running script 'Run Script: Verify Sources'
▸ Processing Framework-Info.plist
▸ Running script 'Run Script: Verify Sources'
▸ Linking AppTestability
^C** BUILD INTERRUPTED **