feat(docs-infra): add API endpoint for checking if PR can have preview (#25671)

There several reasons why PRs cannot have (public) previews:
- The PR did not affect any relevant files (e.g. non-spec files in
  `aio/` or `packages/`).
- The PR cannot be automatically verified as "trusted" (based on its
  author or labels).

Note:
The endpoint does not check whether there currently is a (public)
preview for the specified PR; only whether there can be one.

PR Close #25671

aio/aio-builds-setup/dockerbuild/scripts-js/lib/verify-setup/helper.ts

@@ -105,7 +105,7 @@ class Helper {
     Object.keys(this.portPerScheme).forEach(scheme => suiteFactory(scheme, this.portPerScheme[scheme]));
   }
 
-  public verifyResponse(status: number | [number, string], regex = /^/): VerifyCmdResultFn {
+  public verifyResponse(status: number | [number, string], regex: string | RegExp = /^/): VerifyCmdResultFn {
     let statusCode: number;
     let statusText: string;
 
@@ -180,26 +180,42 @@ class Helper {
   }
 }
 
+interface DefaultCurlOptions {
+  defaultMethod?: CurlOptions['method'];
+  defaultOptions?: CurlOptions['options'];
+  defaultHeaders?: CurlOptions['headers'];
+  defaultData?: CurlOptions['data'];
+  defaultExtraPath?: CurlOptions['extraPath'];
+}
+
 interface CurlOptions {
   method?: string;
   options?: string;
+  headers?: string[];
   data?: any;
   url?: string;
   extraPath?: string;
 }
 
-export function makeCurl(baseUrl: string) {
+export function makeCurl(baseUrl: string, {
+  defaultMethod = 'POST',
+  defaultOptions = '',
+  defaultHeaders = ['Content-Type: application/json'],
+  defaultData = {},
+  defaultExtraPath = '',
+}: DefaultCurlOptions = {}) {
   return function curl({
-    method = 'POST',
-    options = '',
-    data = {},
+    method = defaultMethod,
+    options = defaultOptions,
+    headers = defaultHeaders,
+    data = defaultData,
     url = baseUrl,
-    extraPath = '',
+    extraPath = defaultExtraPath,
   }: CurlOptions) {
     const dataString = data ? JSON.stringify(data) : '';
     const cmd = `curl -iLX ${method} ` +
                 `${options} ` +
-                `--header "Content-Type: application/json" ` +
+                headers.map(header => `--header "${header}" `).join('') +
                 `--data '${dataString}' ` +
                 `${url}${extraPath}`;
     return helper.runCmd(cmd);

aio/aio-builds-setup/dockerbuild/scripts-js/lib/verify-setup/nginx.e2e.ts

@@ -3,6 +3,7 @@ import * as path from 'path';
 import {rm} from 'shelljs';
 import {AIO_BUILDS_DIR, AIO_NGINX_HOSTNAME, AIO_NGINX_PORT_HTTP, AIO_NGINX_PORT_HTTPS} from '../common/env-variables';
 import {computeShortSha} from '../common/utils';
+import {PrNums} from './constants';
 import {helper as h} from './helper';
 import {customMatchers} from './jasmine-custom-matchers';
 
@@ -252,6 +253,42 @@ describe(`nginx`, () => {
     });
 
 
+    describe(`${host}/can-have-public-preview`, () => {
+      const baseUrl = `${scheme}://${host}/can-have-public-preview`;
+
+
+      it('should disallow non-GET requests', async () => {
+        await Promise.all([
+          h.runCmd(`curl -iLX POST ${baseUrl}/42`).then(h.verifyResponse([405, 'Not Allowed'])),
+          h.runCmd(`curl -iLX PUT ${baseUrl}/42`).then(h.verifyResponse([405, 'Not Allowed'])),
+          h.runCmd(`curl -iLX PATCH ${baseUrl}/42`).then(h.verifyResponse([405, 'Not Allowed'])),
+          h.runCmd(`curl -iLX DELETE ${baseUrl}/42`).then(h.verifyResponse([405, 'Not Allowed'])),
+        ]);
+      });
+
+
+      it('should pass requests through to the preview server', async () => {
+        await h.runCmd(`curl -iLX GET ${baseUrl}/${PrNums.CHANGED_FILES_ERROR}`).
+          then(h.verifyResponse(500, /CHANGED_FILES_ERROR/));
+      });
+
+
+      it('should respond with 404 for unknown paths', async () => {
+        const cmdPrefix = `curl -iLX GET ${baseUrl}`;
+
+        await Promise.all([
+          h.runCmd(`${cmdPrefix}/foo/42`).then(h.verifyResponse(404)),
+          h.runCmd(`${cmdPrefix}-foo/42`).then(h.verifyResponse(404)),
+          h.runCmd(`${cmdPrefix}nfoo/42`).then(h.verifyResponse(404)),
+          h.runCmd(`${cmdPrefix}/42/foo`).then(h.verifyResponse(404)),
+          h.runCmd(`${cmdPrefix}/f00`).then(h.verifyResponse(404)),
+          h.runCmd(`${cmdPrefix}/`).then(h.verifyResponse(404)),
+        ]);
+      });
+
+    });
+
+
     describe(`${host}/circle-build`, () => {
 
       it('should disallow non-POST requests', done => {
@@ -287,6 +324,7 @@ describe(`nginx`, () => {
           h.runCmd(`${cmdPrefix}/circle-build/42`).then(h.verifyResponse(404)),
         ]).then(done);
       });
+
     });
 
 

aio/aio-builds-setup/dockerbuild/scripts-js/lib/verify-setup/preview-server.e2e.ts

@@ -18,6 +18,92 @@ describe('preview-server', () => {
   afterEach(() => h.cleanUp());
 
 
+  describe(`${host}/can-have-public-preview`, () => {
+    const curl = makeCurl(`${host}/can-have-public-preview`, {
+      defaultData: null,
+      defaultExtraPath: `/${PrNums.TRUST_CHECK_ACTIVE_TRUSTED_USER}`,
+      defaultHeaders: [],
+      defaultMethod: 'GET',
+    });
+
+
+    it('should disallow non-GET requests', async () => {
+      const bodyRegex = /^Unknown resource in request/;
+
+      await Promise.all([
+        curl({method: 'POST'}).then(h.verifyResponse(404, bodyRegex)),
+        curl({method: 'PUT'}).then(h.verifyResponse(404, bodyRegex)),
+        curl({method: 'PATCH'}).then(h.verifyResponse(404, bodyRegex)),
+        curl({method: 'DELETE'}).then(h.verifyResponse(404, bodyRegex)),
+      ]);
+    });
+
+
+    it('should respond with 404 for unknown paths', async () => {
+      const bodyRegex = /^Unknown resource in request/;
+
+      await Promise.all([
+        curl({extraPath: `/foo/${PrNums.TRUST_CHECK_ACTIVE_TRUSTED_USER}`}).then(h.verifyResponse(404, bodyRegex)),
+        curl({extraPath: `-foo/${PrNums.TRUST_CHECK_ACTIVE_TRUSTED_USER}`}).then(h.verifyResponse(404, bodyRegex)),
+        curl({extraPath: `nfoo/${PrNums.TRUST_CHECK_ACTIVE_TRUSTED_USER}`}).then(h.verifyResponse(404, bodyRegex)),
+        curl({extraPath: `/${PrNums.TRUST_CHECK_ACTIVE_TRUSTED_USER}/foo`}).then(h.verifyResponse(404, bodyRegex)),
+        curl({extraPath: '/f00'}).then(h.verifyResponse(404, bodyRegex)),
+        curl({extraPath: '/'}).then(h.verifyResponse(404, bodyRegex)),
+      ]);
+    });
+
+
+    it('should respond with 500 if checking for significant file changes fails', async () => {
+      await Promise.all([
+        curl({extraPath: `/${PrNums.CHANGED_FILES_404}`}).then(h.verifyResponse(500, /CHANGED_FILES_404/)),
+        curl({extraPath: `/${PrNums.CHANGED_FILES_ERROR}`}).then(h.verifyResponse(500, /CHANGED_FILES_ERROR/)),
+      ]);
+    });
+
+
+    it('should respond with 200 (false) if no significant files were touched', async () => {
+      const expectedResponse = JSON.stringify({
+        canHavePublicPreview: false,
+        reason: 'No significant files touched.',
+      });
+
+      await curl({extraPath: `/${PrNums.CHANGED_FILES_NONE}`}).then(h.verifyResponse(200, expectedResponse));
+    });
+
+
+    it('should respond with 500 if checking "trusted" status fails', async () => {
+      await curl({extraPath: `/${PrNums.TRUST_CHECK_ERROR}`}).then(h.verifyResponse(500, 'TRUST_CHECK_ERROR'));
+    });
+
+
+    it('should respond with 200 (false) if the PR is not automatically verifiable as "trusted"', async () => {
+      const expectedResponse = JSON.stringify({
+        canHavePublicPreview: false,
+        reason: 'Not automatically verifiable as \\"trusted\\".',
+      });
+
+      await Promise.all([
+        curl({extraPath: `/${PrNums.TRUST_CHECK_INACTIVE_TRUSTED_USER}`}).then(h.verifyResponse(200, expectedResponse)),
+        curl({extraPath: `/${PrNums.TRUST_CHECK_UNTRUSTED}`}).then(h.verifyResponse(200, expectedResponse)),
+      ]);
+    });
+
+
+    it('should respond with 200 (true) if the PR can have a public preview', async () => {
+      const expectedResponse = JSON.stringify({
+        canHavePublicPreview: true,
+        reason: null,
+      });
+
+      await Promise.all([
+        curl({extraPath: `/${PrNums.TRUST_CHECK_ACTIVE_TRUSTED_USER}`}).then(h.verifyResponse(200, expectedResponse)),
+        curl({extraPath: `/${PrNums.TRUST_CHECK_TRUSTED_LABEL}`}).then(h.verifyResponse(200, expectedResponse)),
+      ]);
+    });
+
+  });
+
+
   describe(`${host}/circle-build`, () => {
 
     const curl = makeCurl(`${host}/circle-build`);