Support install-only workflow.

.github/workflows/workflow.yml

@@ -45,6 +45,49 @@ jobs:
     outputs:
       changed: ${{ steps.changes.outputs.dist }}
 
+  test-install-only:
+    needs: install-and-build
+    if: ${{ needs.install-and-build.outputs.changed == 'true' }}
+    runs-on: ${{ matrix.os }}
+    name: Install-only on ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: [ubuntu-latest, macos-latest, windows-latest]
+      fail-fast: false
+    steps:
+      - name: Remove pre-installed Pulumi
+        shell: bash
+        env:
+          RUNNER_OS: ${{ matrix.os }}
+        run: |
+          EXT=""
+          if [ "$RUNNER_OS" == "Windows" ]; then
+            EXT=".exe"
+          fi
+
+          if command -v "pulumi${EXT}"; then
+            PULUMI_INSTALL_DIR=$(dirname "$(command -v "pulumi${EXT}")")
+            echo "Deleting Pulumi"
+            rm -v "$PULUMI_INSTALL_DIR"/pulumi*
+          fi
+
+      - uses: actions/checkout@v3
+
+      - name: Download dist artifact
+        uses: actions/download-artifact@v3
+        with:
+          name: dist
+          path: dist
+
+      # If no action is specified, just install.
+      - uses: ./
+        env:
+          PULUMI_CONFIG_PASSPHRASE: not-a-secret
+        with:
+          config-map: "{name: {value: my-pet, secret: false}}"
+
+      - run: pulumi version
+
   test-dotnet-stack:
     needs: install-and-build
     if: ${{ needs.install-and-build.outputs.changed == 'true' }}

CHANGELOG.md

@@ -2,12 +2,16 @@
 
 ## HEAD (Unreleased)
 
+- feat: Support install-only mode similar to
+  [setup-pulumi](https://github.com/marketplace/actions/setup-pulumi)
+  ([#834](https://github.com/pulumi/actions/pull/834))
+
 - fix: allow `comment-on-pr-number` to be used for `${{ github.event }}` types
   other than `pull_request`
   ([#803](https://github.com/pulumi/actions/issues/803))
 
 - bug: Fix installation on Windows.
-([#851](https://github.com/pulumi/actions/pull/851))
+  ([#851](https://github.com/pulumi/actions/pull/851))
 
 ## 4.0.0 (2023-19-01)
 

README.md

@@ -34,12 +34,14 @@ This will check out the existing directory and run `pulumi preview`.
 
 The action can be configured with the following arguments:
 
-- `command` (required) - The command to run as part of the action. Accepted
-  values are `up` (update), `refresh`, `destroy` and `preview`.
+- `command` (optional) - The command to run as part of the action. Accepted
+  values are `up` (alias: update), `refresh`, `destroy`, and `preview`. If
+  unspecified, the action will stop after installing Pulumi.
 
-- `stack-name` (required) - The name of the stack that Pulumi will be operating
+- `stack-name` (optional) - The name of the stack that Pulumi will be operating
   on. Use the fully quaified org-name/stack-name when operating on a stack
-  outside of your individual account.
+  outside of your individual account. This field is required if a `command` was
+  specified.
 
 - `work-dir` (optional) - The location of your Pulumi files. Defaults to `./`.
 
@@ -124,6 +126,17 @@ By default, this action will try to authenticate Pulumi with the
 `PULUMI_ACCESS_TOKEN` then you will need to specify an alternative backend via
 the `cloud-url` argument.
 
+### Installation Only
+
+If you want to only install the Pulumi CLI, omit the `command` field of the
+action.
+
+```yaml
+- uses: pulumi/actions@v4
+```
+
+This will install Pulumi and exit without performing any other operations.
+
 ### Stack Outputs
 
 [Stack outputs](https://www.pulumi.com/docs/intro/concepts/stack/#outputs) are

action.yml

@@ -7,10 +7,10 @@ branding:
 inputs:
   command:
     description: 'Pulumi command to run, eg. up'
-    required: true
+    required: false
   stack-name:
     description: 'Which stack you want to apply to, eg. dev'
-    required: true
+    required: false
   work-dir:
     description: 'Location of your Pulumi files. Defaults to ./'
     required: false

src/__tests__/run.test.ts

@@ -3,6 +3,57 @@ import { login } from '../login';
 
 const spy = jest.spyOn(pulumiCli, 'run');
 
+const installConfig: Record<string, string> = {
+  command: undefined,
+  "pulumi-version": "^2", // test with a non-default value
+};
+
+describe('Config without a provided command', () => {
+  let oldWorkspace = '';
+  beforeEach(() => {
+    spy.mockClear();
+    jest.resetModules();
+    // Save, then restore the current env var for GITHUB_WORKSPACE 
+    oldWorkspace = process.env.GITHUB_WORKSPACE;
+    process.env.GITHUB_WORKSPACE = 'n/a';
+  });
+  afterEach(() => {
+    process.env.GITHUB_WORKSPACE = oldWorkspace;
+  });
+
+  it('should not be validated by makeConfig', async () => {
+    jest.mock('@actions/core', () => ({
+      getInput: jest.fn((name: string) => {
+        return installConfig[name];
+      }),
+      info: jest.fn(),
+    }));
+    jest.mock('@actions/github', () => ({
+      context: {},
+    }));
+    const { makeConfig } = require('../config');
+    await expect(makeConfig())
+      .rejects
+      .toThrow();
+  });
+
+  it('should be validated by makeInstallationConfig', async() => {
+    jest.mock('@actions/core', () => ({
+      getInput: jest.fn((name: string) => {
+        return installConfig[name];
+      }),
+      info: jest.fn(),
+    }));
+    const { makeInstallationConfig } = require('../config');
+    const conf = makeInstallationConfig()
+    expect(conf.success).toBeTruthy();
+    expect(conf.value).toEqual({
+      command: undefined,
+      pulumiVersion: "^2",
+    });
+  });
+});
+
 describe('main.login', () => {
   beforeEach(() => {
     spy.mockClear();

src/config.ts

@@ -4,15 +4,33 @@ import * as rt from 'runtypes';
 import { parseArray, parseBoolean, parseNumber } from './libs/utils';
 
 export const command = rt.Union(
-  rt.Literal('up'),
-  rt.Literal('update'),
-  rt.Literal('refresh'),
   rt.Literal('destroy'),
   rt.Literal('preview'),
+  rt.Literal('refresh'),
+  rt.Literal('up'),
+  rt.Literal('update'),
 );
 
 export type Commands = rt.Static<typeof command>;
 
+// installationConfig is the expected Action inputs when
+// the user intends to download the Pulumi CLI without
+// running any other Pulumi operations.
+// We expect command NOT to be provided.
+export const installationConfig = rt.Record({
+  command: rt.Undefined,
+  pulumiVersion: rt.String,
+});
+
+export type InstallationConfig = rt.Static<typeof installationConfig>;
+
+export function makeInstallationConfig(): rt.Result<InstallationConfig> {
+  return installationConfig.validate({
+    command: getInput('command') || undefined,
+    pulumiVersion: getInput('pulumi-version') || "^3",
+  });
+}
+
 export const options = rt.Partial({
   parallel: rt.Number,
   message: rt.String,

src/main.ts

@@ -8,16 +8,34 @@ import {
 } from '@pulumi/pulumi/automation';
 import invariant from 'ts-invariant';
 import YAML from 'yaml';
-import { Commands, makeConfig } from './config';
+import { Commands, Config, InstallationConfig, makeConfig, makeInstallationConfig } from './config';
 import { environmentVariables } from './libs/envs';
 import { handlePullRequestMessage } from './libs/pr';
 import * as pulumiCli from './libs/pulumi-cli';
 import { login } from './login';
 
 const main = async () => {
+  const downloadConfig = makeInstallationConfig();
+  if (downloadConfig.success) {
+    await installOnly(downloadConfig.value);
+    core.info("Pulumi has been successfully installed. Exiting.");
+    return;
+  }
+
+  // If we get here, we're not in install-only mode.
+  // Attempt to parse the full configuration and run the action.
   const config = await makeConfig();
   core.debug('Configuration is loaded');
+  runAction(config);
+};
+
+// installOnly is the main entrypoint of the program when the user
+// intends to install the Pulumi CLI without running additional commands.
+const installOnly = async (config: InstallationConfig): Promise<void> => {
+  await pulumiCli.downloadCli(config.pulumiVersion);
+}
 
+const runAction = async (config: Config): Promise<void> => {
   await pulumiCli.downloadCli(config.options.pulumiVersion);
   await login(config.cloudUrl, environmentVariables.PULUMI_ACCESS_TOKEN);