feat: idiomize cloudformation intrinsics functions (#1428)

Refactor CloudFormation intrinsic functions so that they will have a more idiomatic shape. They have been converted from classes (e.g. `new FnJoin(...)`) to static methods (e.g. `Fn.join(...)`). Condition functions are mapped to `Fn.conditionXxx` and return an `FnCondition` object.

Furthermore, return type of these static methods are now tokens represented as the resolved type (i.e. `string` or `string[]`) instead of `CloudFormationToken` objects. This allows using these functions and pseudo parameters naturally (instead of requiring the use of `.toString()` or `.toList()`).

Fixes #202

BREAKING CHANGE: CloudFormation intrinsic functions are now represented as static methods under the `Fn` class (e.g. `Fn.join(...)` instead of `new FnJoin(...).toString()`).

Author: Elad Ben-Israel

CHANGELOG.md

@@ -1700,7 +1700,7 @@ Fn.if_(Fn.equals(param.ref, 'True'), 'Encrypted', Pseudo.NO_VALUE)
 After:
 
 ```javascript
-new FnIf(new FnEquals(param.ref, 'True'), 'Encrypted', new AwsNoValue())
+new FnIf(Fn.equals(param.ref, 'True'), 'Encrypted', new AwsNoValue())
 ```
 
 - CloudFormation template options (`templateFormatVersion`, `description` and `transform`) are now grouped under `Stack.templateOptions` instead of directly under `Stack`.

docs/src/cloudformation.rst

@@ -171,8 +171,8 @@ Intrinsic Functions
 
 .. code-block:: js
 
-    import cdk = require('@aws-cdk/cdk');
-    new cdk.FnJoin(",", [...])
+    import { Fn } from'@aws-cdk/cdk';
+    Fn.join(",", [...])
 
 .. _pseudo_parameters:
 

examples/cdk-examples-typescript/advanced-usage/index.ts

@@ -157,7 +157,7 @@ class CloudFormationExample extends cdk.Stack {
     // outputs are constructs the synthesize into the template's "Outputs" section
     new cdk.Output(this, 'Output', {
       description: 'This is an output of the template',
-      value: new cdk.FnConcat(new cdk.AwsAccountId(), '/', param.ref)
+      value: `${new cdk.AwsAccountId()}/${param.ref}`
     });
 
     // stack.templateOptions can be used to specify template-level options
@@ -176,13 +176,13 @@ class CloudFormationExample extends cdk.Stack {
         new cdk.AwsStackName(),
       ],
 
-      // all CloudFormation's intrinsic functions are supported via the `cdk.FnXxx` classes
+      // all CloudFormation's intrinsic functions are supported via the `cdk.Fn.xxx` static methods.
       IntrinsicFunctions: [
-        new cdk.FnAnd(
-          new cdk.FnFindInMap('MyMap', 'K1', 'K2'),
-          new cdk.FnSub('hello ${world}', {
-            world: new cdk.FnBase64(param.ref)  // resolves to { Ref: <param-id> }
-          }))
+        cdk.Fn.join('', [
+          cdk.Fn.findInMap('MyMap', 'K1', 'K2'),
+          cdk.Fn.sub('hello ${world}', {
+            world: cdk.Fn.base64(param.ref)  // resolves to { Ref: <param-id> }
+          }) ])
       ],
     };
   }

package.json

@@ -7,7 +7,7 @@
     "pkglint": "tools/pkglint/bin/pkglint -f ."
   },
   "devDependencies": {
-    "@types/node": "^8.10.38",
+    "@types/node": "8.10.38",
     "@types/nodeunit": "^0.0.30",
     "conventional-changelog-cli": "^2.0.5",
     "lerna": "^3.3.0",

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

@@ -61,9 +61,9 @@ export class DockerImageAsset extends cdk.Construct {
     this.addMetadata(cxapi.ASSET_METADATA, asset);
 
     // parse repository name and tag from the parameter (<REPO_NAME>:<TAG>)
-    const components = new cdk.FnSplit(':', imageNameParameter.value);
-    const repositoryName = new cdk.FnSelect(0, components).toString();
-    const imageTag = new cdk.FnSelect(1, components).toString();
+    const components = cdk.Fn.split(':', imageNameParameter.valueAsString);
+    const repositoryName = cdk.Fn.select(0, components).toString();
+    const imageTag = cdk.Fn.select(1, components).toString();
 
     // Require that repository adoption happens first, so we route the
     // input ARN into the Custom Resource and then get the URI which we use to

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

@@ -110,8 +110,8 @@ export class Asset extends cdk.Construct {
     });
 
     this.s3BucketName = bucketParam.value.toString();
-    this.s3Prefix = new cdk.FnSelect(0, new cdk.FnSplit(cxapi.ASSET_PREFIX_SEPARATOR, keyParam.value)).toString();
-    const s3Filename = new cdk.FnSelect(1, new cdk.FnSplit(cxapi.ASSET_PREFIX_SEPARATOR, keyParam.value)).toString();
+    this.s3Prefix = cdk.Fn.select(0, cdk.Fn.split(cxapi.ASSET_PREFIX_SEPARATOR, keyParam.valueAsString)).toString();
+    const s3Filename = cdk.Fn.select(1, cdk.Fn.split(cxapi.ASSET_PREFIX_SEPARATOR, keyParam.valueAsString)).toString();
     this.s3ObjectKey = `${this.s3Prefix}${s3Filename}`;
 
     this.bucket = s3.BucketRef.import(this, 'AssetBucket', {

packages/@aws-cdk/aws-autoscaling/lib/auto-scaling-group.ts

@@ -222,7 +222,7 @@ export class AutoScalingGroup extends cdk.Construct implements IAutoScalingGroup
 
     // use delayed evaluation
     const machineImage = props.machineImage.getImage(this);
-    const userDataToken = new cdk.Token(() => new cdk.FnBase64((machineImage.os.createUserData(this.userDataLines))));
+    const userDataToken = new cdk.Token(() => cdk.Fn.base64((machineImage.os.createUserData(this.userDataLines))));
     const securityGroupsToken = new cdk.Token(() => this.securityGroups.map(sg => sg.securityGroupId));
 
     const launchConfig = new CfnLaunchConfiguration(this, 'LaunchConfig', {

packages/@aws-cdk/aws-cloudfront/lib/web_distribution.ts

@@ -574,9 +574,7 @@ export class CloudFrontWebDistribution extends cdk.Construct implements route53.
 
       if (originConfig.s3OriginSource && originConfig.s3OriginSource.originAccessIdentity) {
         originProperty.s3OriginConfig = {
-          originAccessIdentity: new cdk.FnConcat(
-            "origin-access-identity/cloudfront/", originConfig.s3OriginSource.originAccessIdentity.ref
-          ),
+          originAccessIdentity: `origin-access-identity/cloudfront/${originConfig.s3OriginSource.originAccessIdentity.ref}`
         };
       } else if (originConfig.s3OriginSource) {
         originProperty.s3OriginConfig = {};

packages/@aws-cdk/aws-cloudtrail/lib/index.ts

@@ -138,7 +138,7 @@ export class CloudTrail extends cdk.Construct {
       .addServicePrincipal(cloudTrailPrincipal));
 
     s3bucket.addToResourcePolicy(new iam.PolicyStatement()
-      .addResource(s3bucket.arnForObjects(new cdk.FnConcat('AWSLogs/', new cdk.AwsAccountId(), "/*")))
+      .addResource(s3bucket.arnForObjects(`AWSLogs/${new cdk.AwsAccountId()}/*`))
       .addActions("s3:PutObject")
       .addServicePrincipal(cloudTrailPrincipal)
       .setCondition("StringEquals", {'s3:x-amz-acl': "bucket-owner-full-control"}));

packages/@aws-cdk/aws-codebuild/lib/project.ts

@@ -495,10 +495,10 @@ export class Project extends ProjectRef {
 
     let cache: CfnProject.ProjectCacheProperty | undefined;
     if (props.cacheBucket) {
-      const cacheDir = props.cacheDir != null ? props.cacheDir : new cdk.AwsNoValue();
+      const cacheDir = props.cacheDir != null ? props.cacheDir : new cdk.AwsNoValue().toString();
       cache = {
         type: 'S3',
-        location: new cdk.FnJoin('/', [props.cacheBucket.bucketName, cacheDir]),
+        location: cdk.Fn.join('/', [props.cacheBucket.bucketName, cacheDir]),
       };
 
       props.cacheBucket.grantReadWrite(this.role);