fix(lambda): Use Alias ARN directly

packages/@aws-cdk/aws-lambda/lib/alias.ts

@@ -1,9 +1,8 @@
-import iam = require('@aws-cdk/aws-iam');
+import cloudwatch = require('@aws-cdk/aws-cloudwatch');
 import cdk = require('@aws-cdk/cdk');
 import { FunctionBase, FunctionImportProps, IFunction } from './function-base';
 import { Version } from './lambda-version';
 import { CfnAlias } from './lambda.generated';
-import { Permission } from './permission';
 
 /**
  * Properties for a new Lambda alias
@@ -68,11 +67,6 @@ export class Alias extends FunctionBase {
    */
   public readonly functionArn: string;
 
-  /**
-   * Role associated with this alias
-   */
-  public readonly role?: iam.IRole | undefined;
-
   protected readonly canCreatePermissions: boolean = true; // Not used anyway
 
   /**
@@ -85,7 +79,7 @@ export class Alias extends FunctionBase {
 
     this.underlyingLambda = props.version.lambda;
 
-    new CfnAlias(this, 'Resource', {
+    const alias = new CfnAlias(this, 'Resource', {
       name: props.aliasName,
       description: props.description,
       functionName: this.underlyingLambda.functionName,
@@ -95,8 +89,25 @@ export class Alias extends FunctionBase {
 
     // Not actually the name, but an ARN can be used in all places
     // where the name is expected, and an ARN can refer to an Alias.
-    this.functionName = `${props.version.lambda.functionArn}:${props.aliasName}`;
-    this.functionArn = `${props.version.lambda.functionArn}:${props.aliasName}`;
+    this.functionName = `${this.underlyingLambda.functionName}:${props.aliasName}`;
+    this.functionArn = alias.aliasArn;
+  }
+
+  /**
+   * Role associated with this alias
+   */
+  public get role() {
+    return this.underlyingLambda.role;
+  }
+
+  public metric(metricName: string, props?: cloudwatch.MetricCustomization): cloudwatch.Metric {
+    return super.metric(metricName, {
+      dimensions: {
+        FunctionName: this.underlyingLambda.functionName,
+        Resource: this.functionArn
+      },
+      ...(props || {})
+    });
   }
 
   public export(): FunctionImportProps {
@@ -105,11 +116,6 @@ export class Alias extends FunctionBase {
     };
   }
 
-  public addPermission(name: string, permission: Permission) {
-    // Forward addPermission() to the underlying Lambda object
-    this.underlyingLambda.addPermission(name, permission);
-  }
-
   /**
    * Calculate the routingConfig parameter from the input props
    */

packages/@aws-cdk/aws-lambda/lib/function-base.ts

@@ -175,7 +175,7 @@ export abstract class FunctionBase extends cdk.Construct implements IFunction  {
     new CfnPermission(this, id, {
       action,
       principal,
-      functionName: this.functionName,
+      functionName: this.functionArn,
       eventSourceToken: permission.eventSourceToken,
       sourceAccount: permission.sourceAccount,
       sourceArn: permission.sourceArn,

packages/@aws-cdk/aws-lambda/test/integ.bucket-notifications.expected.json

@@ -110,7 +110,10 @@
       "Properties": {
         "Action": "lambda:InvokeFunction",
         "FunctionName": {
-          "Ref": "MyFunction3BAA72D1"
+          "Fn::GetAtt": [
+            "MyFunction3BAA72D1",
+            "Arn"
+          ]
         },
         "Principal": "s3.amazonaws.com",
         "SourceAccount": {
@@ -129,7 +132,10 @@
       "Properties": {
         "Action": "lambda:InvokeFunction",
         "FunctionName": {
-          "Ref": "MyFunction3BAA72D1"
+          "Fn::GetAtt": [
+            "MyFunction3BAA72D1",
+            "Arn"
+          ]
         },
         "Principal": "s3.amazonaws.com",
         "SourceAccount": {

packages/@aws-cdk/aws-lambda/test/integ.events.expected.json

@@ -65,7 +65,10 @@
       "Properties": {
         "Action": "lambda:InvokeFunction",
         "FunctionName": {
-          "Ref": "MyFunc8A243A2C"
+          "Fn::GetAtt": [
+            "MyFunc8A243A2C",
+            "Arn"
+          ]
         },
         "Principal": "events.amazonaws.com",
         "SourceArn": {
@@ -81,7 +84,10 @@
       "Properties": {
         "Action": "lambda:InvokeFunction",
         "FunctionName": {
-          "Ref": "MyFunc8A243A2C"
+          "Fn::GetAtt": [
+            "MyFunc8A243A2C",
+            "Arn"
+          ]
         },
         "Principal": "events.amazonaws.com",
         "SourceArn": {

packages/@aws-cdk/aws-lambda/test/test.alias.ts

@@ -1,3 +1,5 @@
+import cloudwatch = require('@aws-cdk/aws-cloudwatch');
+
 import { beASupersetOfTemplate, expect, haveResource } from '@aws-cdk/assert';
 import { AccountPrincipal } from '@aws-cdk/aws-iam';
 import { Stack } from '@aws-cdk/cdk';
@@ -123,10 +125,50 @@ export = {
 
     // THEN
     expect(stack).to(haveResource('AWS::Lambda::Permission', {
-      FunctionName: stack.node.resolve(fn.functionName),
+      FunctionName: {
+        Ref: "Alias325C5727"
+      },
       Principal: "123456"
     }));
 
+    test.done();
+  },
+
+  'metric adds Resource: aliasArn to dimensions'(test: Test) {
+    const stack = new Stack();
+
+    // GIVEN
+    const fn = new lambda.Function(stack, 'MyLambda', {
+      code: new lambda.InlineCode('hello()'),
+      handler: 'index.hello',
+      runtime: lambda.Runtime.NodeJS610,
+    });
+
+    const version = fn.addVersion('1');
+    const alias = new lambda.Alias(stack, 'Alias', { aliasName: 'prod', version });
+
+    // WHEN
+    new cloudwatch.Alarm(stack, 'Alarm', {
+      metric: alias.metric('Test'),
+      alarmName: 'Test',
+      threshold: 1,
+      evaluationPeriods: 1
+    });
+
+    expect(stack).to(haveResource('AWS::CloudWatch::Alarm', {
+      Dimensions: [{
+        Name: "FunctionName",
+        Value: {
+          Ref: "MyLambdaCCE802FB"
+        }
+      }, {
+        Name: "Resource",
+        Value: {
+          Ref: "Alias325C5727"
+        }
+      }]
+    }));
+
     test.done();
   }
 };

packages/@aws-cdk/aws-lambda/test/test.lambda.ts

@@ -153,8 +153,8 @@ export = {
           "Handler": "bar",
           "Role": {
             "Fn::GetAtt": [
-            "MyLambdaServiceRole4539ECB6",
-            "Arn"
+              "MyLambdaServiceRole4539ECB6",
+              "Arn"
             ]
           },
           "Runtime": "python2.7"
@@ -168,7 +168,10 @@ export = {
           "Properties": {
           "Action": "lambda:*",
           "FunctionName": {
-            "Ref": "MyLambdaCCE802FB"
+            "Fn::GetAtt": [
+              "MyLambdaCCE802FB",
+              "Arn"
+            ]
           },
           "Principal": "s3.amazonaws.com",
           "SourceAccount": {
@@ -269,14 +272,24 @@ export = {
 
     expect(stack).to(haveResource('AWS::Lambda::Permission', {
       "Action": "lambda:InvokeFunction",
-      "FunctionName": { "Ref": lambdaId },
+      "FunctionName": {
+        "Fn::GetAtt": [
+          lambdaId,
+          "Arn"
+        ]
+      },
       "Principal": "events.amazonaws.com",
       "SourceArn": { "Fn::GetAtt": [ "Rule4C995B7F", "Arn" ] }
     }));
 
     expect(stack).to(haveResource('AWS::Lambda::Permission', {
       "Action": "lambda:InvokeFunction",
-      "FunctionName": { "Ref": "MyLambdaCCE802FB" },
+      "FunctionName": {
+        "Fn::GetAtt": [
+          lambdaId,
+          "Arn"
+        ]
+      },
       "Principal": "events.amazonaws.com",
       "SourceArn": { "Fn::GetAtt": [ "Rule270732244", "Arn" ] }
     }));

packages/@aws-cdk/aws-lambda/test/test.subscriptiondestination.ts

@@ -30,7 +30,12 @@ export = {
     // THEN: Lambda has permissions to be invoked by CWL
     expect(stack).to(haveResource('AWS::Lambda::Permission', {
       Action: "lambda:InvokeFunction",
-      FunctionName: { Ref: "MyLambdaCCE802FB" },
+      FunctionName: {
+        "Fn::GetAtt": [
+          "MyLambdaCCE802FB",
+          "Arn"
+        ]
+      },
       Principal: { "Fn::Join": ["", ["logs.", {Ref: "AWS::Region"}, ".amazonaws.com"]] }
     }));