wrapper: Write stdout/stderr data to stream when received

.changes/unreleased/BUG FIXES-20240425-104731.yaml

@@ -0,0 +1,6 @@
+kind: BUG FIXES
+body: 'wrapper: Fix wrapper to output to stdout and stderr immediately when data is
+  received'
+time: 2024-04-25T10:47:31.19951-04:00
+custom:
+  Issue: "395"

.github/workflows/data/delay/main.tf

@@ -0,0 +1,11 @@
+resource "null_resource" "previous" {}
+
+resource "time_sleep" "wait_30_seconds" {
+  depends_on = [null_resource.previous]
+
+  create_duration = "30s"
+}
+
+resource "null_resource" "next" {
+  depends_on = [time_sleep.wait_30_seconds]
+}

.github/workflows/setup-terraform.yml

@@ -304,7 +304,6 @@ jobs:
       id: plan
       run: terraform plan
 
-
   terraform-stdout-wrapper:
     name: 'Terraform STDOUT'
     runs-on: ${{ matrix.os }}
@@ -370,3 +369,33 @@ jobs:
     - name: Terraform Output to JQ
       id: output
       run: terraform output -json | jq '.pet.value'
+
+  # This test has an artificial delay for testing the streaming of STDOUT 
+  terraform-wrapper-delayed-apply:
+    name: 'Terraform Delayed Apply'
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: [ubuntu-latest, windows-latest, macos-latest]
+    defaults:
+      run:
+        shell: bash
+        working-directory: ./.github/workflows/data/delay
+    steps:
+    - name: Checkout
+      uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4.1.1
+
+    - name: Setup Terraform
+      uses: ./
+      with:
+        terraform_wrapper: true
+
+    - name: Terraform Init
+      run: terraform init
+
+    - name: Terraform Format
+      run: terraform fmt -check
+
+    - name: Terraform Apply
+      id: apply
+      run: terraform apply -auto-approve

dist/index1.js

@@ -27599,13 +27599,18 @@ module.exports = {
  * console.log(listener.contents);
  */
 class OutputListener {
-  constructor () {
+  constructor (streamWriter) {
     this._buff = [];
+    this._streamWriter = streamWriter;
   }
 
   get listener () {
     const listen = function listen (data) {
       this._buff.push(data);
+
+      if (this._streamWriter) {
+        this._streamWriter.write(data);
+      }
     };
     return listen.bind(this);
   }
@@ -27946,9 +27951,9 @@ async function checkTerraform () {
   // This will fail if Terraform isn't found, which is what we want
   await checkTerraform();
 
-  // Create listeners to receive output (in memory) as well
-  const stdout = new OutputListener();
-  const stderr = new OutputListener();
+  // Create listeners to receive output (in memory)
+  const stdout = new OutputListener(process.stdout);
+  const stderr = new OutputListener(process.stderr);
   const listeners = {
     stdout: stdout.listener,
     stderr: stderr.listener
@@ -27963,10 +27968,6 @@ async function checkTerraform () {
   };
   const exitCode = await exec(pathToCLI, args, options);
 
-  // Pass-through stdout/err as `exec` won't due to `silent: true` option
-  process.stdout.write(stdout.contents);
-  process.stderr.write(stderr.contents);
-
   // Set outputs, result, exitcode, and stderr
   core.setOutput('stdout', stdout.contents);
   core.setOutput('stderr', stderr.contents);

wrapper/lib/output-listener.js

@@ -20,13 +20,18 @@
  * console.log(listener.contents);
  */
 class OutputListener {
-  constructor () {
+  constructor (streamWriter) {
     this._buff = [];
+    this._streamWriter = streamWriter;
   }
 
   get listener () {
     const listen = function listen (data) {
       this._buff.push(data);
+
+      if (this._streamWriter) {
+        this._streamWriter.write(data);
+      }
     };
     return listen.bind(this);
   }

wrapper/terraform.js

@@ -21,9 +21,9 @@ async function checkTerraform () {
   // This will fail if Terraform isn't found, which is what we want
   await checkTerraform();
 
-  // Create listeners to receive output (in memory) as well
-  const stdout = new OutputListener();
-  const stderr = new OutputListener();
+  // Create listeners to receive output (in memory)
+  const stdout = new OutputListener(process.stdout);
+  const stderr = new OutputListener(process.stderr);
   const listeners = {
     stdout: stdout.listener,
     stderr: stderr.listener
@@ -38,10 +38,6 @@ async function checkTerraform () {
   };
   const exitCode = await exec(pathToCLI, args, options);
 
-  // Pass-through stdout/err as `exec` won't due to `silent: true` option
-  process.stdout.write(stdout.contents);
-  process.stderr.write(stderr.contents);
-
   // Set outputs, result, exitcode, and stderr
   core.setOutput('stdout', stdout.contents);
   core.setOutput('stderr', stderr.contents);

wrapper/test/output-listener.test.js

@@ -6,12 +6,31 @@
 const OutputListener = require('../lib/output-listener');
 
 describe('output-listener', () => {
-  it('receives and exposes data', () => {
+  it('receives and buffers data to .contents', () => {
     const listener = new OutputListener();
     const listen = listener.listener;
+
     listen(Buffer.from('foo'));
     listen(Buffer.from('bar'));
     listen(Buffer.from('baz'));
+
     expect(listener.contents).toEqual('foobarbaz');
   });
+
+  it('receives and writes data to stream immediately', () => {
+    const mockWrite = jest.fn();
+    const listener = new OutputListener({ write: mockWrite });
+    const listen = listener.listener;
+
+    listen(Buffer.from('first write'));
+    expect(mockWrite.mock.lastCall[0]).toStrictEqual(Buffer.from('first write'));
+
+    listen(Buffer.from('second write'));
+    expect(mockWrite.mock.lastCall[0]).toStrictEqual(Buffer.from('second write'));
+
+    listen(Buffer.from('third write'));
+    expect(mockWrite.mock.lastCall[0]).toStrictEqual(Buffer.from('third write'));
+
+    expect(mockWrite).toBeCalledTimes(3);
+  });
 });