refactor(core): improvements to Construct API (#2767)

Closes #1934

BREAKING CHANGE:
* **core:** `node.stack` is now `Stack.of(construct)` (fixes #2766)
* **core:** `node.resolve` has been moved to `stack.resolve`.
* **core:** `node.stringifyJson` has been moved to `stack.stringifyJson`.
* **core:** `node.validateTree` is now `ConstructNode.validate(node)`
* **core:** `node.prepareTree` is now `ConstructNode.prepare(node)`
* **core:** `node.getContext` is now `node.tryGetContext`
* **core:** `node.recordReference` is now `node.addReference`
* **core:** `node.apply` is now `node.applyAspect`
* **core:** `node.ancestors()` is now `node.scopes`
* **core:** `node.required` has been removed.
* **core:** `node.typename` has been removed.
* **core:** `node.addChild` is now private
* **core:** `node.findReferences()` is now `node.references`
* **core:** `node.findDependencies()` is now `node.dependencies`
* **core:** `stack.dependencies()` is now `stack.dependencies`
* **core:** `CfnElement.stackPath` has been removed.
* **core:** `CloudFormationLang` is now internal (use `stack.toJsonString()`)

Author: Elad Ben-Israel

packages/@aws-cdk/app-delivery/lib/pipeline-deploy-stack-action.ts

@@ -105,7 +105,7 @@ export class PipelineDeployStackAction extends cdk.Construct {
   constructor(scope: cdk.Construct, id: string, props: PipelineDeployStackActionProps) {
     super(scope, id);
 
-    if (!cdk.environmentEquals(props.stack.env, this.node.stack.env)) {
+    if (!cdk.environmentEquals(props.stack.env, cdk.Stack.of(this).env)) {
       // FIXME: Add the necessary to extend to stacks in a different account
       throw new Error(`Cross-environment deployment is not supported`);
     }

packages/@aws-cdk/app-delivery/test/test.pipeline-deploy-stack-action.ts

@@ -6,6 +6,7 @@ import cpactions = require('@aws-cdk/aws-codepipeline-actions');
 import iam = require('@aws-cdk/aws-iam');
 import s3 = require('@aws-cdk/aws-s3');
 import cdk = require('@aws-cdk/cdk');
+import { ConstructNode } from '@aws-cdk/cdk';
 import cxapi = require('@aws-cdk/cx-api');
 import fc = require('fast-check');
 import nodeunit = require('nodeunit');
@@ -289,7 +290,7 @@ export = nodeunit.testCase({
           for (let i = 0 ; i < assetCount ; i++) {
             deployedStack.node.addMetadata(cxapi.ASSET_METADATA, {});
           }
-          test.deepEqual(action.node.validateTree().map(x => x.message),
+          test.deepEqual(ConstructNode.validate(action.node).map(x => x.message),
             [`Cannot deploy the stack DeployedStack because it references ${assetCount} asset(s)`]);
         }
       )

packages/@aws-cdk/assets/lib/asset.ts

@@ -198,7 +198,7 @@ export class Asset extends cdk.Construct implements IAsset {
    * (e.g. "Code" for AWS::Lambda::Function)
    */
   public addResourceMetadata(resource: cdk.CfnResource, resourceProperty: string) {
-    if (!this.node.getContext(cxapi.ASSET_RESOURCE_METADATA_ENABLED_CONTEXT)) {
+    if (!this.node.tryGetContext(cxapi.ASSET_RESOURCE_METADATA_ENABLED_CONTEXT)) {
       return; // not enabled
     }
 

packages/@aws-cdk/assets/lib/staging.ts

@@ -57,7 +57,7 @@ export class Staging extends Construct {
     this.copyOptions = props;
     this.sourceHash = fingerprint(this.sourcePath, props);
 
-    const stagingDisabled = this.node.getContext(cxapi.DISABLE_ASSET_STAGING_CONTEXT);
+    const stagingDisabled = this.node.tryGetContext(cxapi.DISABLE_ASSET_STAGING_CONTEXT);
     if (stagingDisabled) {
       this.stagedPath = this.sourcePath;
     } else {

packages/@aws-cdk/assets/test/test.asset.ts

@@ -31,7 +31,7 @@ export = {
     // verify that now the template contains parameters for this asset
     const session = app.synth();
 
-    test.deepEqual(stack.node.resolve(entry!.data), {
+    test.deepEqual(stack.resolve(entry!.data), {
       path: SAMPLE_ASSET_DIR,
       id: 'MyStackMyAssetBDDF29E3',
       packaging: 'zip',
@@ -84,7 +84,7 @@ export = {
     // synthesize first so "prepare" is called
     const template = SynthUtils.synthesize(stack).template;
 
-    test.deepEqual(stack.node.resolve(entry!.data), {
+    test.deepEqual(stack.resolve(entry!.data), {
       path: 'asset.78add9eaf468dfa2191da44a7da92a21baba4c686cf6053d772556768ef21197.txt',
       packaging: 'file',
       id: 'MyAsset',

packages/@aws-cdk/aws-apigateway/lib/deployment.ts

@@ -1,4 +1,4 @@
-import { Construct, DeletionPolicy, Resource, Token } from '@aws-cdk/cdk';
+import { Construct, DeletionPolicy, Resource, Stack, Token } from '@aws-cdk/cdk';
 import crypto = require('crypto');
 import { CfnDeployment, CfnDeploymentProps } from './apigateway.generated';
 import { IRestApi } from './restapi';
@@ -99,7 +99,7 @@ class LatestDeploymentResource extends CfnDeployment {
   constructor(scope: Construct, id: string, props: CfnDeploymentProps) {
     super(scope, id, props);
 
-    this.originalLogicalId = this.node.stack.logicalIds.getLogicalId(this);
+    this.originalLogicalId = Stack.of(this).logicalIds.getLogicalId(this);
   }
 
   /**
@@ -121,12 +121,14 @@ class LatestDeploymentResource extends CfnDeployment {
    * add via `addToLogicalId`.
    */
   protected prepare() {
+    const stack = Stack.of(this);
+
     // if hash components were added to the deployment, we use them to calculate
     // a logical ID for the deployment resource.
     if (this.hashComponents.length > 0) {
       const md5 = crypto.createHash('md5');
       this.hashComponents
-        .map(c => this.node.resolve(c))
+        .map(c => stack.resolve(c))
         .forEach(c => md5.update(JSON.stringify(c)));
 
       this.overrideLogicalId(this.originalLogicalId + md5.digest("hex"));

packages/@aws-cdk/aws-apigateway/lib/integrations/aws.ts

@@ -1,4 +1,5 @@
 import cdk = require('@aws-cdk/cdk');
+import { Stack } from '@aws-cdk/cdk';
 import { Integration, IntegrationOptions, IntegrationType } from '../integration';
 import { Method } from '../method';
 import { parseAwsApiCall } from '../util';
@@ -80,7 +81,7 @@ export class AwsIntegration extends Integration {
       integrationHttpMethod: props.integrationHttpMethod || 'POST',
       uri: new cdk.Token(() => {
         if (!this.scope) { throw new Error('AwsIntegration must be used in API'); }
-        return this.scope.node.stack.formatArn({
+        return Stack.of(this.scope).formatArn({
           service: 'apigateway',
           account: backend,
           resource: apiType,

packages/@aws-cdk/aws-apigateway/lib/method.ts

@@ -1,4 +1,4 @@
-import { Construct, Resource } from '@aws-cdk/cdk';
+import { Construct, Resource, Stack } from '@aws-cdk/cdk';
 import { CfnMethod, CfnMethodProps } from './apigateway.generated';
 import { ConnectionType, Integration } from './integration';
 import { MockIntegration } from './integrations/mock';
@@ -197,7 +197,7 @@ export class Method extends Resource {
     } else if (options.credentialsPassthrough) {
       // arn:aws:iam::*:user/*
       // tslint:disable-next-line:max-line-length
-      credentials = this.node.stack.formatArn({ service: 'iam', region: '', account: '*', resource: 'user', sep: '/', resourceName: '*' });
+      credentials = Stack.of(this).formatArn({ service: 'iam', region: '', account: '*', resource: 'user', sep: '/', resourceName: '*' });
     }
 
     return {

packages/@aws-cdk/aws-apigateway/lib/restapi.ts

@@ -1,5 +1,5 @@
 import iam = require('@aws-cdk/aws-iam');
-import { CfnOutput, Construct, IResource as IResourceBase, Resource } from '@aws-cdk/cdk';
+import { CfnOutput, Construct, IResource as IResourceBase, Resource, Stack } from '@aws-cdk/cdk';
 import { ApiKey, IApiKey } from './api-key';
 import { CfnAccount, CfnRestApi } from './apigateway.generated';
 import { Deployment } from './deployment';
@@ -284,7 +284,7 @@ export class RestApi extends Resource implements IRestApi {
       method = '*';
     }
 
-    return this.node.stack.formatArn({
+    return Stack.of(this).formatArn({
       service: 'execute-api',
       resource: this.restApiId,
       sep: '/',
@@ -343,7 +343,7 @@ export class RestApi extends Resource implements IRestApi {
   private configureCloudWatchRole(apiResource: CfnRestApi) {
     const role = new iam.Role(this, 'CloudWatchRole', {
       assumedBy: new iam.ServicePrincipal('apigateway.amazonaws.com'),
-      managedPolicyArns: [ this.node.stack.formatArn({
+      managedPolicyArns: [ Stack.of(this).formatArn({
         service: 'iam',
         region: '',
         account: 'aws',

packages/@aws-cdk/aws-apigateway/lib/stage.ts

@@ -1,4 +1,4 @@
-import { Construct, Resource } from '@aws-cdk/cdk';
+import { Construct, Resource, Stack } from '@aws-cdk/cdk';
 import { CfnStage } from './apigateway.generated';
 import { Deployment } from './deployment';
 import { IRestApi } from './restapi';
@@ -209,7 +209,7 @@ export class Stage extends Resource {
     if (!path.startsWith('/')) {
       throw new Error(`Path must begin with "/": ${path}`);
     }
-    return `https://${this.restApi.restApiId}.execute-api.${this.node.stack.region}.${this.node.stack.urlSuffix}/${this.stageName}${path}`;
+    return `https://${this.restApi.restApiId}.execute-api.${Stack.of(this).region}.${Stack.of(this).urlSuffix}/${this.stageName}${path}`;
   }
 
   private renderMethodSettings(props: StageProps): CfnStage.MethodSettingProperty[] | undefined {