StepFunctionsRestApi implemented along with unit and integration test…

…ing.

Fixed Integration test and generated expected json for stepFunctionsRestApi Stack deployment.
closes aws#15081.

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

@@ -21,6 +21,7 @@ export * from './authorizers';
 export * from './access-log';
 export * from './api-definition';
 export * from './gateway-response';
+export * from './stepFunctions-api';
 
 // AWS::ApiGateway CloudFormation Resources:
 export * from './apigateway.generated';

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

@@ -2,3 +2,4 @@ export * from './aws';
 export * from './lambda';
 export * from './http';
 export * from './mock';
+export * from './stepFunctions';

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

@@ -0,0 +1,155 @@
+import * as iam from '@aws-cdk/aws-iam';
+import * as sfn from '@aws-cdk/aws-stepfunctions';
+import { Token } from '@aws-cdk/core';
+import { IntegrationConfig, IntegrationOptions, PassthroughBehavior } from '../integration';
+import { Method } from '../method';
+import { AwsIntegration } from './aws';
+
+/**
+ * StepFunctionsIntegrationOptions
+ */
+export interface StepFunctionsIntegrationOptions extends IntegrationOptions {
+  /**
+   * Use proxy integration or normal (request/response mapping) integration.
+   *
+   * @default false
+   */
+  readonly proxy?: boolean;
+
+  /**
+   * Check if cors is enabled
+   * @default false
+   */
+  readonly corsEnabled?: boolean;
+
+}
+/**
+ * Integrates a Synchronous Express State Machine from AWS Step Functions to an API Gateway method.
+ *
+ * @example
+ *
+ *    const handler = new sfn.StateMachine(this, 'MyStateMachine', ...);
+ *    api.addMethod('GET', new StepFunctionsIntegration(handler));
+ *
+ */
+
+export class StepFunctionsIntegration extends AwsIntegration {
+  private readonly handler: sfn.IStateMachine;
+
+  constructor(handler: sfn.IStateMachine, options: StepFunctionsIntegrationOptions = { }) {
+
+    const integResponse = getIntegrationResponse();
+    const requestTemplate = getRequestTemplates(handler);
+
+    if (options.corsEnabled) {
+      super({
+        proxy: options.proxy,
+        service: 'states',
+        action: 'StartSyncExecution',
+        options,
+      });
+    } else {
+      super({
+        proxy: options.proxy,
+        service: 'states',
+        action: 'StartSyncExecution',
+        options: {
+          credentialsRole: options.credentialsRole,
+          integrationResponses: integResponse,
+          passthroughBehavior: PassthroughBehavior.NEVER,
+          requestTemplates: requestTemplate,
+        },
+      });
+    }
+
+    this.handler = handler;
+  }
+
+  public bind(method: Method): IntegrationConfig {
+    const bindResult = super.bind(method);
+    const principal = new iam.ServicePrincipal('apigateway.amazonaws.com');
+
+    this.handler.grantExecution(principal, 'states:StartSyncExecution');
+
+    let stateMachineName;
+
+    if (this.handler instanceof sfn.StateMachine) {
+      //if not imported, extract the name from the CFN layer to reach the
+      //literal value if it is given (rather than a token)
+      stateMachineName = (this.handler.node.defaultChild as sfn.CfnStateMachine).stateMachineName;
+    } else {
+      stateMachineName = 'StateMachine-' + (String(this.handler.stack.node.addr).substring(0, 8));
+    }
+
+    let deploymentToken;
+
+    if (!Token.isUnresolved(stateMachineName)) {
+      deploymentToken = JSON.stringify({ stateMachineName });
+    }
+    return {
+      ...bindResult,
+      deploymentToken,
+    };
+
+  }
+}
+
+function getIntegrationResponse() {
+  const errorResponse = [
+    {
+      selectionPattern: '4\\d{2}',
+      statusCode: '400',
+      responseTemplates: {
+        'application/json': `{
+            "error": "Bad input!"
+          }`,
+      },
+    },
+    {
+      selectionPattern: '5\\d{2}',
+      statusCode: '500',
+      responseTemplates: {
+        'application/json': '"error": $input.path(\'$.error\')',
+      },
+    },
+  ];
+
+  const integResponse = [
+    {
+      statusCode: '200',
+      responseTemplates: {
+        'application/json': `#set($inputRoot = $input.path('$'))
+                #if($input.path('$.status').toString().equals("FAILED"))
+                    #set($context.responseOverride.status = 500)
+                    { "error": "$input.path('$.error')" }
+                #else
+                    $input.path('$.output')
+                #end`,
+      },
+    },
+    ...errorResponse,
+  ];
+
+  return integResponse;
+}
+
+function getRequestTemplates(handler: sfn.IStateMachine) {
+  const templateString = getTemplateString(handler);
+
+  const requestTemplate: { [contenType:string] : string } =
+    {
+      'application/json': templateString,
+    };
+
+  return requestTemplate;
+}
+
+function getTemplateString(handler: sfn.IStateMachine): string {
+  const templateString: string = `
+      #set($inputRoot = $input.path('$')) {
+          "input": "$util.escapeJavaScript($input.json(\'$\'))",
+          "stateMachineArn": "${handler.stateMachineArn}"
+        }`;
+
+  return templateString;
+}

packages/@aws-cdk/aws-apigateway/lib/stepFunctions-api.ts

@@ -0,0 +1,124 @@
+import * as iam from '@aws-cdk/aws-iam';
+import * as sfn from '@aws-cdk/aws-stepfunctions';
+import { Construct } from 'constructs';
+import { RestApi, RestApiProps } from '.';
+import { StepFunctionsIntegration } from './integrations/stepFunctions';
+import { Model } from './model';
+
+/**
+ * StepFunctionsRestApiProps
+ */
+export interface StepFunctionsRestApiProps extends RestApiProps {
+/**
+ * The default State Machine that handles all requests from this API.
+ *
+ * This handler will be used as a the default integration for all methods in
+ * this API, unless specified otherwise in `addMethod`.
+ */
+  readonly handler: sfn.IStateMachine;
+
+  /**
+  * If true, route all requests to the State Machine
+  *
+  * If set to false, you will need to explicitly define the API model using
+  * `addResource` and `addMethod` (or `addProxy`).
+  *
+  * @default true
+  */
+  readonly proxy?: boolean;
+
+  /**
+  * Rest API props options
+  * @default - no options.
+  *
+  */
+  readonly options?: RestApiProps;
+}
+
+/**
+ * Defines an API Gateway REST API with a Synchrounous Express State Machine as a proxy integration.
+ *
+ */
+
+export class StepFunctionsRestApi extends RestApi {
+  constructor(scope: Construct, id: string, props: StepFunctionsRestApiProps) {
+    if ((props.options && props.options.defaultIntegration) || props.defaultIntegration) {
+      throw new Error('Cannot specify "defaultIntegration" since Step Functions integration is automatically defined');
+    }
+
+    const apiRole = getRole(scope, props);
+    const methodResp = getMethodResponse();
+
+    let corsEnabled;
+
+    if (props.defaultCorsPreflightOptions !== undefined) {
+      corsEnabled = true;
+    } else {
+      corsEnabled = false;
+    }
+
+    super(scope, id, {
+      defaultIntegration: new StepFunctionsIntegration(props.handler, {
+        credentialsRole: apiRole,
+        proxy: false, //proxy not avaialble for Step Functions yet
+        corsEnabled: corsEnabled,
+      }),
+      ...props.options,
+      ...props,
+    });
+
+    this.root.addMethod('ANY', new StepFunctionsIntegration(props.handler, {
+      credentialsRole: apiRole,
+    }), {
+      methodResponses: [
+        ...methodResp,
+      ],
+    });
+  }
+}
+
+function getRole(scope: Construct, props: StepFunctionsRestApiProps): iam.Role {
+  const apiName: string = props.handler + '-apiRole';
+  const apiRole = new iam.Role(scope, apiName, {
+    assumedBy: new iam.ServicePrincipal('apigateway.amazonaws.com'),
+  });
+
+  apiRole.attachInlinePolicy(
+    new iam.Policy(scope, 'AllowStartSyncExecution', {
+      statements: [
+        new iam.PolicyStatement({
+          actions: ['states:StartSyncExecution'],
+          effect: iam.Effect.ALLOW,
+          resources: [props.handler.stateMachineArn],
+        }),
+      ],
+    }),
+  );
+
+  return apiRole;
+}
+
+function getMethodResponse() {
+  const methodResp = [
+    {
+      statusCode: '200',
+      responseModels: {
+        'application/json': Model.EMPTY_MODEL,
+      },
+    },
+    {
+      statusCode: '400',
+      responseModels: {
+        'application/json': Model.ERROR_MODEL,
+      },
+    },
+    {
+      statusCode: '500',
+      responseModels: {
+        'application/json': Model.ERROR_MODEL,
+      },
+    },
+  ];
+
+  return methodResp;
+}

packages/@aws-cdk/aws-apigateway/package.json

@@ -92,7 +92,8 @@
     "@aws-cdk/aws-s3-assets": "0.0.0",
     "@aws-cdk/core": "0.0.0",
     "@aws-cdk/cx-api": "0.0.0",
-    "constructs": "^3.3.69"
+    "constructs": "^3.3.69",
+    "@aws-cdk/aws-stepfunctions": "0.0.0"
   },
   "homepage": "https://github.com/aws/aws-cdk",
   "peerDependencies": {
@@ -108,7 +109,8 @@
     "@aws-cdk/aws-s3-assets": "0.0.0",
     "@aws-cdk/core": "0.0.0",
     "@aws-cdk/cx-api": "0.0.0",
-    "constructs": "^3.3.69"
+    "constructs": "^3.3.69",
+    "@aws-cdk/aws-stepfunctions": "0.0.0"
   },
   "engines": {
     "node": ">= 10.13.0 <13 || >=13.7.0"
@@ -318,6 +320,7 @@
       "attribute-tag:@aws-cdk/aws-apigateway.RequestAuthorizer.authorizerArn",
       "attribute-tag:@aws-cdk/aws-apigateway.TokenAuthorizer.authorizerArn",
       "attribute-tag:@aws-cdk/aws-apigateway.RestApi.restApiName",
+      "attribute-tag:@aws-cdk/aws-apigateway.StepFunctionsRestApi.restApiName",
       "attribute-tag:@aws-cdk/aws-apigateway.SpecRestApi.restApiName",
       "attribute-tag:@aws-cdk/aws-apigateway.LambdaRestApi.restApiName",
       "from-method:@aws-cdk/aws-apigateway.Stage",