Allow specifying stdin

packages/exec/__tests__/exec.test.ts

@@ -286,6 +286,27 @@ describe('@actions/exec', () => {
     expect(stderrCalled).toBeTruthy()
   })
 
+  it('Handles stdin', async () => {
+    const waitForInput: string = path.join(
+      __dirname,
+      'scripts',
+      'wait-for-input.sh'
+    )
+
+    const _testExecOptions = getExecOptions()
+
+    _testExecOptions.listeners = {
+      stdout: (data: Buffer) => {
+        expect(data).toEqual(Buffer.from('this is my input\n'))
+      }
+    }
+
+    _testExecOptions.stdin = Buffer.from('this is my input')
+
+    const exitCode = await exec.exec(`"${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.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. */
+  stdin?: 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 +524,16 @@ export class ToolRunner extends events.EventEmitter {
           resolve(exitCode)
         }
       })
+
+      if (this.options.stdin) {
+        if (!cp.stdin) {
+          throw new Error('child process missing stdin')
+        }
+
+        cp.stdin.setDefaultEncoding('utf-8')
+        cp.stdin.write(this.options.stdin)
+        cp.stdin.end()
+      }
     })
   }
 }