feat: Expose getIamPolicy support for project (#302)

* feat: expose getIamPolicy for Project Object

src/project.ts

@@ -35,6 +35,41 @@ export interface ProjectCreateCallback {
   ): void;
 }
 
+export interface Expression {
+  expression: string;
+  title: string;
+  description: string;
+  location: string;
+}
+export interface Binding {
+  role: string;
+  members: string[];
+  condition: Expression;
+}
+export interface AuditLogConfig {
+  logType: string;
+  exemptedMembers: string[];
+}
+export interface AuditConfig {
+  service: string;
+  auditLogConfigs: AuditLogConfig[];
+}
+
+export interface Policy {
+  bindings: Binding[];
+  auditConfigs: AuditConfig[];
+  etag: string;
+  version: number;
+}
+
+export type GetIamPolicyResponse = [Policy];
+export interface GetIamPolicyCallback {
+  (err: Error | null, policy?: Policy): void;
+}
+export interface GetIamPolicyOptions {
+  requestedPolicyVersion: number;
+}
+
 /**
  * A Project object allows you to interact with a Google Cloud Platform project.
  *
@@ -288,6 +323,73 @@ class Project extends ServiceObject {
     super.create(callback);
   }
 
+  getIamPolicy(options?: GetIamPolicyOptions): Promise<GetIamPolicyResponse>;
+  getIamPolicy(callback: GetIamPolicyCallback): void;
+  getIamPolicy(
+    options: GetIamPolicyOptions,
+    callback: GetIamPolicyCallback
+  ): void;
+  /**
+   * @typedef {array} GetIamPolicyResponse
+   * @property {Policy} 0 This project's IAM [policy]{@link https://cloud.google.com/resource-manager/reference/rest/Shared.Types/Policy}.
+   */
+  /**
+   * @callback GetIamPolicyCallback
+   * @param {?Error} err Request error, if any.
+   * @param {Policy} policy This project's IAM [policy]{@link https://cloud.google.com/resource-manager/reference/rest/Shared.Types/Policy}.
+   */
+  /**
+   * Get the IAM policy for this project.
+   *
+   * @see [projects: getIamPolicy API Documentation]{@link https://cloud.google.com/resource-manager/reference/rest/v1/projects/getIamPolicy}
+   *
+   * @param {GetIamPolicyOptions} [options] Options object to get IAM policy.
+   * @param {GetIamPolicyCallback} [callback] Callback function.
+   * @returns {Promise<GetIamPolicyResponse>}
+   *
+   * @example
+   * const {Resource} = require('@google-cloud/resource');
+   * const resource = new Resource();
+   * const project = resource.project('grape-spaceship-123');
+   *
+   * project.getIamPolicy((err, policy) => {
+   *   if (!err) {
+   *     console.log(policy).
+   *   }
+   * });
+   *
+   * //-
+   * // If the callback is omitted, we'll return a Promise.
+   * //-
+   * project.getIamPolicy().then((data) => {
+   *   const policy = data[0];
+   * });
+   */
+  getIamPolicy(
+    optionsOrCallback?: GetIamPolicyCallback | GetIamPolicyOptions,
+    callback?: GetIamPolicyCallback
+  ): void | Promise<GetIamPolicyResponse> {
+    const options =
+      typeof optionsOrCallback === 'object' ? optionsOrCallback : {};
+    callback =
+      typeof optionsOrCallback === 'function' ? optionsOrCallback : callback;
+
+    this.request(
+      {
+        method: 'POST',
+        uri: ':getIamPolicy',
+        body: {
+          options,
+        },
+      },
+      (err, resp) => {
+        callback!(err, resp);
+      }
+    );
+  }
+
+  restore(): Promise<RestoreResponse>;
+  restore(callback: RestoreCallback): void;
   /**
    * Restore a project.
    *
@@ -318,8 +420,6 @@ class Project extends ServiceObject {
    *   const apiResponse = data[0];
    * });
    */
-  restore(): Promise<RestoreResponse>;
-  restore(callback: RestoreCallback): void;
   restore(callback?: RestoreCallback): void | Promise<RestoreResponse> {
     callback = callback || util.noop;
     this.request(

system-test/resource.ts

@@ -57,6 +57,15 @@ describe('Resource', () => {
       const [metadata] = await project.getMetadata();
       assert.notStrictEqual(metadata.projectId, undefined);
     });
+
+    it('should get Iam policy', done => {
+      project.getIamPolicy((err, policy) => {
+        assert.ifError(err);
+        assert.notStrictEqual(policy!.etag, undefined);
+        assert.strictEqual(typeof policy!.version, 'number');
+        done();
+      });
+    });
   });
 
   // Auth through the gcloud SDK is required to:

test/project.ts

@@ -25,6 +25,7 @@ import * as promisify from '@google-cloud/promisify';
 import * as assert from 'assert';
 import {describe, it} from 'mocha';
 import * as proxyquire from 'proxyquire';
+import {Policy} from '../src/project';
 
 let promisified = false;
 const fakePromisify = Object.assign({}, promisify, {
@@ -106,6 +107,56 @@ describe('Project', () => {
     });
   });
 
+  describe('getIamPolicy', () => {
+    const error = new Error('Error.');
+    const policy = {
+      version: 1,
+      bindings: [
+        {
+          members: ['serviceAccount:fakeemail@project.iam.gserviceaccount.com'],
+          role: 'roles/appengine.appAdmin',
+        },
+      ],
+      auditConfigs: [
+        {
+          auditLogConfigs: [
+            {
+              logType: 'ADMIN_READ',
+            },
+          ],
+          service: 'spanner.googleapis.com',
+        },
+      ],
+      etag: 'BwWf8AIJOb4=',
+    };
+
+    beforeEach(() => {
+      project.request = (
+        reqOpts: DecorateRequestOptions,
+        callback: Function
+      ) => {
+        callback(error, policy);
+      };
+    });
+
+    it('should make the correct API request', done => {
+      project.request = (reqOpts: DecorateRequestOptions) => {
+        assert.strictEqual(reqOpts.method, 'POST');
+        assert.strictEqual(reqOpts.uri, ':getIamPolicy');
+        done();
+      };
+      project.getIamPolicy(assert.ifError);
+    });
+
+    it('should execute the callback with error & API response', done => {
+      project.getIamPolicy((err: Error, apiResponse_: Policy) => {
+        assert.strictEqual(err, error);
+        assert.strictEqual(apiResponse_, policy);
+        done();
+      });
+    });
+  });
+
   describe('restore', () => {
     const error = new Error('Error.');
     const apiResponse = {a: 'b', c: 'd'};