Added feature to pick from multiple sample backends.

packages/create-pwa/lib/index.js

@@ -1,17 +1,36 @@
 const { basename, resolve } = require('path');
 const os = require('os');
+const fetch = require('node-fetch');
 const changeCase = require('change-case');
 const inquirer = require('inquirer');
 const execa = require('execa');
 const chalk = require('chalk');
 const gitUserInfo = require('git-user-info');
 const isInvalidPath = require('is-invalid-path');
 const isValidNpmName = require('is-valid-npm-name');
+const { uniqBy } = require('lodash');
+
 const pkg = require('../package.json');
 const {
-    sampleBackends
+    sampleBackends: defaultSampleBackends
 } = require('@magento/pwa-buildpack/lib/cli/create-project');
 
+const removeDuplicateBackends = backendEnvironments =>
+    uniqBy(backendEnvironments, 'url');
+
+const fetchSampleBackends = async () => {
+    try {
+        const res = await fetch(
+            'https://fvp0esmt8f.execute-api.us-east-1.amazonaws.com/default/getSampleBackends'
+        );
+        const { sampleBackends } = await res.json();
+
+        return sampleBackends.environments;
+    } catch {
+        return [];
+    }
+};
+
 module.exports = async () => {
     console.log(chalk.greenBright(`${pkg.name} v${pkg.version}`));
     console.log(
@@ -20,6 +39,16 @@ module.exports = async () => {
     const userAgent = process.env.npm_config_user_agent || '';
     const isYarn = userAgent.includes('yarn');
 
+    const sampleBackendEnvironments = await fetchSampleBackends();
+    const filteredBackendEnvironments = removeDuplicateBackends([
+        ...sampleBackendEnvironments,
+        ...defaultSampleBackends.environments
+    ]);
+    const sampleBackends = {
+        ...defaultSampleBackends,
+        environments: filteredBackendEnvironments
+    };
+
     const questions = [
         {
             name: 'directory',

packages/create-pwa/package.json

@@ -37,6 +37,8 @@
     "inquirer": "^6.3.1",
     "is-invalid-path": "^1.0.2",
     "is-valid-npm-name": "^0.0.4",
+    "lodash": "~4.17.11",
+    "node-fetch": "~2.3.0",
     "webpack": "^4.29.5"
   }
 }

packages/extensions/venia-sample-backends/__tests__/__snapshots__/intercept.spec.js.snap

@@ -0,0 +1,21 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`should call onFail if backend is inactive 1`] = `
+"https://www.magento-backend-2.3.4.com/ is inactive. Please consider using one of these other backends: 
+
+ [{\\"name\\":\\"2.3.3-venia-cloud\\",\\"description\\":\\"Magento 2.3.3 with Venia sample data installed\\",\\"url\\":\\"https://master-7rqtwti-mfwmkrjfqvbjk.us-4.magentosite.cloud/\\"}] 
+"
+`;
+
+exports[`should call onFail with a different error message if environments is empty 1`] = `
+"https://www.magento-backend-2.3.4.com/ is inactive. Please consider using one of these other backends: 
+
+ [{\\"name\\":\\"2.3.3-venia-cloud\\",\\"description\\":\\"Magento 2.3.3 with Venia sample data installed\\",\\"url\\":\\"https://master-7rqtwti-mfwmkrjfqvbjk.us-4.magentosite.cloud/\\"}] 
+"
+`;
+
+exports[`should log warning message in the console 1`] = `
+"
+ venia-sample-backends is a Dev only extension, please remove it from the project's package.json before going to production. 
+"
+`;

packages/extensions/venia-sample-backends/__tests__/intercept.spec.js

@@ -0,0 +1,75 @@
+jest.mock('node-fetch');
+const fetch = require('node-fetch');
+
+const { validateSampleBackend } = require('../intercept');
+
+const env = {
+    MAGENTO_BACKEND_URL: 'https://www.magento-backend-2.3.4.com/'
+};
+const onFail = jest.fn().mockName('onFail');
+const debug = jest.fn().mockName('debug');
+
+const args = { env, onFail, debug };
+
+beforeAll(() => {
+    console.warn = jest.fn();
+});
+
+test('should not call onFail if backend is active', async () => {
+    fetch.mockResolvedValueOnce({ ok: true });
+
+    await validateSampleBackend(args);
+
+    expect(onFail).not.toHaveBeenCalled();
+});
+
+test('should call onFail if backend is inactive', async () => {
+    fetch.mockResolvedValueOnce({ ok: false }).mockResolvedValueOnce({
+        json: jest.fn().mockResolvedValue({
+            sampleBackends: {
+                environments: [
+                    {
+                        name: '2.3.3-venia-cloud',
+                        description:
+                            'Magento 2.3.3 with Venia sample data installed',
+                        url:
+                            'https://master-7rqtwti-mfwmkrjfqvbjk.us-4.magentosite.cloud/'
+                    },
+                    {
+                        name: '2.3.4-venia-cloud',
+                        description:
+                            'Magento 2.3.4 with Venia sample data installed',
+                        url: 'https://www.magento-backend-2.3.4.com/'
+                    }
+                ]
+            }
+        })
+    });
+
+    await validateSampleBackend(args);
+
+    expect(onFail).toHaveBeenCalled();
+    expect(onFail.mock.calls[0][0]).toMatchSnapshot();
+});
+
+test('should call onFail with a different error message if environments is empty', async () => {
+    fetch.mockResolvedValueOnce({ ok: false }).mockResolvedValueOnce({
+        json: jest.fn().mockResolvedValue({
+            sampleBackends: {
+                environments: []
+            }
+        })
+    });
+
+    await validateSampleBackend(args);
+
+    expect(onFail).toHaveBeenCalled();
+    expect(onFail.mock.calls[0][0]).toMatchSnapshot();
+});
+
+test('should log warning message in the console', async () => {
+    await validateSampleBackend(args);
+
+    expect(console.warn).toHaveBeenCalled();
+    expect(console.warn.mock.calls[0][0]).toMatchSnapshot();
+});

packages/extensions/venia-sample-backends/intercept.js

@@ -0,0 +1,91 @@
+const fetch = require('node-fetch');
+
+const isBackendActive = async (env, debug) => {
+    try {
+        const magentoBackend = env.MAGENTO_BACKEND_URL;
+        const res = await fetch(magentoBackend);
+
+        return res.ok;
+    } catch (err) {
+        debug(err);
+
+        return false;
+    }
+};
+
+const fetchBackends = async debug => {
+    try {
+        const res = await fetch(
+            'https://fvp0esmt8f.execute-api.us-east-1.amazonaws.com/default/getSampleBackends'
+        );
+        const { sampleBackends } = await res.json();
+
+        return sampleBackends.environments;
+    } catch (err) {
+        debug(err);
+
+        return [];
+    }
+};
+
+/**
+ * Validation function to check if the backend being used is one of the sample backends provided
+ * by PWA Studio. If yes, the function validates if the backend is active. If not, it reports an
+ * error by calling the onFail function. In the error being reported, it sends the other sample
+ * backends that the developers can use.
+ *
+ * @param {Object} config.env - The ENV provided to the app, usually avaialable through process.ENV
+ * @param {Function} config.onFail - callback function to call on validation fail
+ * @param {Function} config.debug - function to log debug messages in console in debug mode
+ *
+ * To watch the debug messages, run the command with DEBUG=*runEnvValidators*
+ */
+const validateSampleBackend = async config => {
+    console.warn(
+        "\n venia-sample-backends is a Dev only extension, please remove it from the project's package.json before going to production. \n"
+    );
+
+    const { env, onFail, debug } = config;
+
+    const backendIsActive = await isBackendActive(env, debug);
+
+    if (!backendIsActive) {
+        debug(`${env.MAGENTO_BACKEND_URL} is inactive`);
+
+        debug('Fetching other backends');
+
+        const sampleBackends = await fetchBackends(debug);
+        const otherBackends = sampleBackends.filter(
+            ({ url }) => url !== env.MAGENTO_BACKEND_URL
+        );
+
+        debug('PWA Studio supports the following backends', sampleBackends);
+
+        debug('Reporting backend URL validation failure');
+        if (otherBackends.length) {
+            onFail(
+                `${
+                    env.MAGENTO_BACKEND_URL
+                } is inactive. Please consider using one of these other backends: \n\n ${JSON.stringify(
+                    otherBackends
+                )} \n`
+            );
+        } else {
+            onFail(
+                `${
+                    env.MAGENTO_BACKEND_URL
+                } is inactive. Please consider using an active backend \n`
+            );
+        }
+    } else {
+        debug(`${env.MAGENTO_BACKEND_URL} is active`);
+    }
+};
+
+module.exports = targets => {
+    targets
+        .of('@magento/pwa-buildpack')
+        .validateEnv.tapPromise(validateSampleBackend);
+};
+
+module.exports.validateSampleBackend = validateSampleBackend;

packages/extensions/venia-sample-backends/package.json

@@ -0,0 +1,24 @@
+{
+  "name": "@magento/venia-sample-backends",
+  "version": "0.0.1",
+  "publishConfig": {
+    "access": "public"
+  },
+  "description": "Provides demo backends and backend validation utils for PWA Studio.",
+  "main": "./intercept.js",
+  "scripts": {
+    "clean": " ",
+    "test": "jest"
+  },
+  "repository": "github:magento/pwa-studio",
+  "license": "(OSL-3.0 OR AFL-3.0)",
+  "peerDependencies": {
+    "@magento/pwa-buildpack": "~7.0.0",
+    "node-fetch": "~2.3.0"
+  },
+  "pwa-studio": {
+    "targets": {
+      "intercept": "./intercept"
+    }
+  }
+}

packages/extensions/venia-sample-language-packs/package.json

@@ -20,4 +20,4 @@
       "intercept": "./i18n-intercept"
     }
   }
-}
+}

packages/pwa-buildpack/lib/BuildBus/declare-base.js

@@ -153,7 +153,26 @@ module.exports = targets => {
          * @member {tapable.AsyncSeriesHook}
          * @param {transformUpwardIntercept} interceptor
          */
-        transformUpward: new targets.types.AsyncSeries(['definitions'])
+        transformUpward: new targets.types.AsyncSeries(['definitions']),
+
+        /**
+         * Collect all ENV validation functions that will run against the
+         * project's ENV. The functions can be async and they will run in
+         * parallel. If a validation function wants to stop the whole process
+         * for instance in case of a serious security issue, it can do so
+         * by throwing an error. If it wants to report an error, it can do so
+         * by using the onFail callback provided as an argument. A validation
+         * function can submit multiple errors by calling the onFail function
+         * multiple times. All the errors will be queued into an array and
+         * displayed on the console at the end of the process.
+         *
+         * @example
+         * targets.of('@magento/pwa-buildpack').validateEnv.tapPromise(validateBackendUrl);
+         *
+         * @member {tapable.AsyncParallelHook}
+         * @param {envValidationInterceptor} validator
+         */
+        validateEnv: new targets.types.AsyncParallel(['validator'])
     };
 
     /**
@@ -282,3 +301,29 @@ module.exports = targets => {
  * @param {object} definition - Parsed UPWARD definition object.
  * @returns {Promise}
  */
+
+/** Type definitions related to: validateEnv */
+
+/**
+ * Intercept function signature for the validateEnv target.
+ *
+ * Interceptors of the `validateEnv` target receive a config object.
+ * The config object contains the project env, an onFail callback and
+ * the debug function to be used in case of the debug mode to log more
+ * inforamtion to the console.
+ *
+ * This Target can be used asynchronously in the parallel mode. If a
+ * validator needs to stop the process immediately, it can throw an error.
+ * If it needs to report an error but not stop the whole process, it can do
+ * so by calling the onFail function with the error message it wants to report.
+ * It can call the onFail multiple times if it wants to report multiple errors.
+ *
+ * All the errors will be queued and printed into the console at the end of the
+ * validation process and the build process will be stopeed.
+ *
+ * @callback envValidationInterceptor
+ * @param {Object} config.env - Project ENV
+ * @param {Function} config.onFail - On fail callback
+ * @param {Function} config.debug - Debug function to be used for additional reporting in debug mode
+ * @returns {Boolean}
+ */

packages/pwa-buildpack/lib/Utilities/__tests__/__snapshots__/loadEnvironment.spec.js.snap

@@ -19,3 +19,9 @@ Array [
   ],
 ]
 `;
+
+exports[`throws on load if variable defs are invalid 1`] = `
+"Bad environment variable definition. Section inscrutable variable {
+ \\"type\\": \\"ineffable\\"
+} declares an unknown type ineffable"
+`;

packages/pwa-buildpack/lib/Utilities/__tests__/__snapshots__/runEnvValidators.spec.js.snap

@@ -0,0 +1,7 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`should throw error if there are validation errors reported by interceptors 1`] = `
+"Environment has 2 validation errors: 
+ (1) Danger,
+ (2) Another error"
+`;