Add getExecOutput function (#814)

* Add getExecOutput function

* Add tests for exec output

* Modify tests to not rely on buffer size, but only test larger output

* Handle split multi-byte characters + PR feedback

* Fix tests

* Lint

* Update how split byte are sent for tests

packages/exec/__tests__/exec.test.ts

@@ -636,6 +636,165 @@ describe('@actions/exec', () => {
     expect(output.trim()).toBe(`args[0]: "hello"${os.EOL}args[1]: "world"`)
   })
 
+  it('correctly outputs for getExecOutput', async () => {
+    const stdErrPath: string = path.join(
+      __dirname,
+      'scripts',
+      'stderroutput.js'
+    )
+    const stdOutPath: string = path.join(
+      __dirname,
+      'scripts',
+      'stdoutoutput.js'
+    )
+    const nodePath: string = await io.which('node', true)
+
+    const {exitCode: exitCodeOut, stdout} = await exec.getExecOutput(
+      `"${nodePath}"`,
+      [stdOutPath],
+      getExecOptions()
+    )
+
+    expect(exitCodeOut).toBe(0)
+    expect(stdout).toBe('this is output to stdout')
+
+    const {exitCode: exitCodeErr, stderr} = await exec.getExecOutput(
+      `"${nodePath}"`,
+      [stdErrPath],
+      getExecOptions()
+    )
+    expect(exitCodeErr).toBe(0)
+    expect(stderr).toBe('this is output to stderr')
+  })
+
+  it('correctly outputs for getExecOutput with additional listeners', async () => {
+    const stdErrPath: string = path.join(
+      __dirname,
+      'scripts',
+      'stderroutput.js'
+    )
+    const stdOutPath: string = path.join(
+      __dirname,
+      'scripts',
+      'stdoutoutput.js'
+    )
+
+    const nodePath: string = await io.which('node', true)
+    let listenerOut = ''
+
+    const {exitCode: exitCodeOut, stdout} = await exec.getExecOutput(
+      `"${nodePath}"`,
+      [stdOutPath],
+      {
+        ...getExecOptions(),
+        listeners: {
+          stdout: data => {
+            listenerOut = data.toString()
+          }
+        }
+      }
+    )
+
+    expect(exitCodeOut).toBe(0)
+    expect(stdout).toBe('this is output to stdout')
+    expect(listenerOut).toBe('this is output to stdout')
+
+    let listenerErr = ''
+    const {exitCode: exitCodeErr, stderr} = await exec.getExecOutput(
+      `"${nodePath}"`,
+      [stdErrPath],
+      {
+        ...getExecOptions(),
+        listeners: {
+          stderr: data => {
+            listenerErr = data.toString()
+          }
+        }
+      }
+    )
+    expect(exitCodeErr).toBe(0)
+    expect(stderr).toBe('this is output to stderr')
+    expect(listenerErr).toBe('this is output to stderr')
+  })
+
+  it('correctly outputs for getExecOutput when total size exceeds buffer size', async () => {
+    const stdErrPath: string = path.join(
+      __dirname,
+      'scripts',
+      'stderroutput.js'
+    )
+    const stdOutPath: string = path.join(
+      __dirname,
+      'scripts',
+      'stdoutoutputlarge.js'
+    )
+
+    const nodePath: string = await io.which('node', true)
+    let listenerOut = ''
+
+    const {exitCode: exitCodeOut, stdout} = await exec.getExecOutput(
+      `"${nodePath}"`,
+      [stdOutPath],
+      {
+        ...getExecOptions(),
+        listeners: {
+          stdout: data => {
+            listenerOut += data.toString()
+          }
+        }
+      }
+    )
+
+    expect(exitCodeOut).toBe(0)
+    expect(Buffer.byteLength(stdout || '', 'utf8')).toBe(2 ** 25)
+    expect(Buffer.byteLength(listenerOut, 'utf8')).toBe(2 ** 25)
+
+    let listenerErr = ''
+    const {exitCode: exitCodeErr, stderr} = await exec.getExecOutput(
+      `"${nodePath}"`,
+      [stdErrPath],
+      {
+        ...getExecOptions(),
+        listeners: {
+          stderr: data => {
+            listenerErr = data.toString()
+          }
+        }
+      }
+    )
+    expect(exitCodeErr).toBe(0)
+    expect(stderr).toBe('this is output to stderr')
+    expect(listenerErr).toBe('this is output to stderr')
+  })
+
+  it('correctly outputs for getExecOutput with multi-byte characters', async () => {
+    const stdOutPath: string = path.join(
+      __dirname,
+      'scripts',
+      'stdoutputspecial.js'
+    )
+
+    const nodePath: string = await io.which('node', true)
+    let numStdOutBufferCalls = 0
+    const {exitCode: exitCodeOut, stdout} = await exec.getExecOutput(
+      `"${nodePath}"`,
+      [stdOutPath],
+      {
+        ...getExecOptions(),
+        listeners: {
+          stdout: () => {
+            numStdOutBufferCalls += 1
+          }
+        }
+      }
+    )
+
+    expect(exitCodeOut).toBe(0)
+    //one call for each half of the © character, ensuring it was actually split and not sent together
+    expect(numStdOutBufferCalls).toBe(2)
+    expect(stdout).toBe('©')
+  })
+
   if (IS_WINDOWS) {
     it('Exec roots relative tool path using process.cwd (Windows path separator)', async () => {
       let exitCode: number

packages/exec/__tests__/scripts/stdoutoutputlarge.js

@@ -0,0 +1,3 @@
+//Default highWaterMark for readable stream buffers us 64K (2^16)
+//so we go over that to get more than a buffer's worth
+process.stdout.write('a\n'.repeat(2**24));

packages/exec/__tests__/scripts/stdoutputspecial.js

@@ -0,0 +1,5 @@
+//first half of © character
+process.stdout.write(Buffer.from([0xC2]), (err) => {
+    //write in the callback so that the second byte is sent separately
+    process.stdout.write(Buffer.from([0xA9])) //second half of © character
+})

packages/exec/src/exec.ts

@@ -1,7 +1,8 @@
-import {ExecOptions} from './interfaces'
+import {StringDecoder} from 'string_decoder'
+import {ExecOptions, ExecOutput, ExecListeners} from './interfaces'
 import * as tr from './toolrunner'
 
-export {ExecOptions}
+export {ExecOptions, ExecOutput, ExecListeners}
 
 /**
  * Exec a command.
@@ -28,3 +29,63 @@ export async function exec(
   const runner: tr.ToolRunner = new tr.ToolRunner(toolPath, args, options)
   return runner.exec()
 }
+
+/**
+ * Exec a command and get the output.
+ * Output will be streamed to the live console.
+ * Returns promise with the exit code and collected stdout and stderr
+ *
+ * @param     commandLine           command to execute (can include additional args). Must be correctly escaped.
+ * @param     args                  optional arguments for tool. Escaping is handled by the lib.
+ * @param     options               optional exec options.  See ExecOptions
+ * @returns   Promise<ExecOutput>   exit code, stdout, and stderr
+ */
+
+export async function getExecOutput(
+  commandLine: string,
+  args?: string[],
+  options?: ExecOptions
+): Promise<ExecOutput> {
+  let stdout = ''
+  let stderr = ''
+
+  //Using string decoder covers the case where a mult-byte character is split
+  const stdoutDecoder = new StringDecoder('utf8')
+  const stderrDecoder = new StringDecoder('utf8')
+
+  const originalStdoutListener = options?.listeners?.stdout
+  const originalStdErrListener = options?.listeners?.stderr
+
+  const stdErrListener = (data: Buffer): void => {
+    stderr += stderrDecoder.write(data)
+    if (originalStdErrListener) {
+      originalStdErrListener(data)
+    }
+  }
+
+  const stdOutListener = (data: Buffer): void => {
+    stdout += stdoutDecoder.write(data)
+    if (originalStdoutListener) {
+      originalStdoutListener(data)
+    }
+  }
+
+  const listeners: ExecListeners = {
+    ...options?.listeners,
+    stdout: stdOutListener,
+    stderr: stdErrListener
+  }
+
+  const exitCode = await exec(commandLine, args, {...options, listeners})
+
+  //flush any remaining characters
+  stdout += stdoutDecoder.end()
+  stderr += stderrDecoder.end()
+
+  //return undefined for stdout/stderr if they are empty
+  return {
+    exitCode,
+    stdout,
+    stderr
+  }
+}

packages/exec/src/interfaces.ts

@@ -34,15 +34,39 @@ export interface ExecOptions {
   input?: Buffer
 
   /** optional. Listeners for output. Callback functions that will be called on these events */
-  listeners?: {
+  listeners?: ExecListeners
+}
+
+/**
+ * Interface for the output of getExecOutput()
+ */
+export interface ExecOutput {
+  /**The exit code of the process */
+  exitCode: number
+
+  /**The entire stdout of the process as a string */
+  stdout: string
+
+  /**The entire stderr of the process as a string */
+  stderr: string
+}
+
+/**
+ * The user defined listeners for an exec call
+ */
+export interface ExecListeners {
+  /** A call back for each buffer of stdout */
   stdout?: (data: Buffer) => void
 
+  /** A call back for each buffer of stderr */
   stderr?: (data: Buffer) => void
 
+  /** A call back for each line of stdout */
   stdline?: (data: string) => void
 
+  /** A call back for each line of stderr */
   errline?: (data: string) => void
 
+  /** A call back for each debug log */
   debug?: (data: string) => void
-  }
 }