Allow specifying stdin (#360)

* Allow specifying stdin

packages/exec/__tests__/exec.test.ts

@@ -286,6 +286,52 @@ describe('@actions/exec', () => {
     expect(stderrCalled).toBeTruthy()
   })
 
+  it('Handles stdin shell', async () => {
+    let command: string
+    if (IS_WINDOWS) {
+      command = 'wait-for-input.cmd'
+    } else {
+      command = 'wait-for-input.sh'
+    }
+
+    const waitForInput: string = path.join(__dirname, 'scripts', command)
+
+    const _testExecOptions = getExecOptions()
+
+    _testExecOptions.listeners = {
+      stdout: (data: Buffer) => {
+        expect(data).toEqual(Buffer.from(`this is my input${os.EOL}`))
+      }
+    }
+
+    _testExecOptions.input = Buffer.from('this is my input')
+
+    const exitCode = await exec.exec(`"${waitForInput}"`, [], _testExecOptions)
+    expect(exitCode).toBe(0)
+  })
+
+  it('Handles stdin js', async () => {
+    const waitForInput: string = path.join(
+      __dirname,
+      'scripts',
+      'wait-for-input.js'
+    )
+
+    const _testExecOptions = getExecOptions()
+
+    _testExecOptions.listeners = {
+      stdout: (data: Buffer) => {
+        expect(data).toEqual(Buffer.from(`this is my input`))
+      }
+    }
+
+    _testExecOptions.input = Buffer.from('this is my input')
+
+    const nodePath = await io.which('node', true)
+    const exitCode = await exec.exec(nodePath, [waitForInput], _testExecOptions)
+    expect(exitCode).toBe(0)
+  })
+
   it('Handles child process holding streams open', async function() {
     const semaphorePath = path.join(
       getTestTemp(),

packages/exec/__tests__/scripts/wait-for-input.cmd

@@ -0,0 +1,3 @@
+@echo off
+set /p var=
+echo %var%

packages/exec/__tests__/scripts/wait-for-input.js

@@ -0,0 +1,3 @@
+var fs = require('fs')
+var data = fs.readFileSync(0, 'utf-8')
+process.stdout.write(data)

packages/exec/__tests__/scripts/wait-for-input.sh

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+
+read var
+echo $var

packages/exec/src/interfaces.ts

@@ -30,6 +30,9 @@ export interface ExecOptions {
   /** optional. How long in ms to wait for STDIO streams to close after the exit event of the process before terminating. defaults to 10000 */
   delay?: number
 
+  /** optional. input to write to the process on STDIN. */
+  input?: Buffer
+
   /** optional. Listeners for output. Callback functions that will be called on these events */
   listeners?: {
     stdout?: (data: Buffer) => void

packages/exec/src/toolrunner.ts

@@ -524,6 +524,14 @@ export class ToolRunner extends events.EventEmitter {
           resolve(exitCode)
         }
       })
+
+      if (this.options.input) {
+        if (!cp.stdin) {
+          throw new Error('child process missing stdin')
+        }
+
+        cp.stdin.end(this.options.input)
+      }
     })
   }
 }