chore: update README and keywords

Author: riywo

.projenrc.js

@@ -18,6 +18,12 @@ const project = new awscdk.AwsCdkConstructLibrary({
   minNodeVersion: '18.12.1',
   packageManager: 'yarn',
   npmAccess: NpmAccess.PUBLIC,
+  keywords: [
+    'appsync',
+    'stepfunctions',
+    'Serverless',
+    'State Machine',
+  ],
   githubOptions: {
     projenCredentials: GithubCredentials.fromApp(),
   },

README.md

@@ -1 +1,101 @@
-# cdk-appsync-data-source-sfn-express
+[![npm version](https://badge.fury.io/js/@opsbr%2Fcdk-appsync-data-source-sfn-express.svg)](https://badge.fury.io/js/@opsbr%2Fcdk-appsync-data-source-sfn-express) [![release](https://github.com/opsbr/cdk-appsync-data-source-sfn-express/actions/workflows/release.yml/badge.svg)](https://github.com/opsbr/cdk-appsync-data-source-sfn-express/actions/workflows/release.yml)
+
+# cdk-appsync-data-source-sfn-express
+
+A CDK construct to create an AWS AppSync data source to call AWS Step Functions express workflows.
+
+[![View on Construct Hub](https://constructs.dev/badge?package=%40opsbr%2Fcdk-appsync-data-source-sfn-express)](https://constructs.dev/packages/@opsbr/cdk-appsync-data-source-sfn-express)
+## What is this?
+
+This construct provides an HTTP data source for AWS AppSync that uses IAM authentication and
+calls AWS Step Functions API - `StartSyncExecution`. This is a stop-gap solution until AWS
+provides a native integration with this API like they have for AWS Lambda or Amazon DynamoDB.
+
+Then, the construct can easily create a resolver to call this API, which means you can build
+AppSync GraphQL API by running a Step Functions state machine synchronously just like Amazon
+API Gateway already has, too.
+
+Also, this is a showcase for how to use HTTP data source for non-RESTful AWS endpoints.
+
+## Usage
+
+```typescript
+declare const api: appsync.CfnGraphQLApi;
+declare const stateMachine: stepfunctions.StateMachine;
+
+const schema = new appsync.CfnGraphQLSchema(stack, 'Schema', {
+  apiId: api.attrApiId,
+  definition: `
+    type Query {
+      getPost(id: Int): Post
+    }
+    type Post {
+      id: Int
+      title: String
+    }
+  `,
+});
+
+const sfnExpressDataSource = new AppSyncDataSourceStepFunctionsExpress(stack, 'SfnExpressDataSource', {
+  apiId: api.attrApiId,
+});
+
+sfnExpressDataSource.createStateMachineResolver('SumResolver', {
+  stateMachine: sumStateMachine,
+  schema,
+  typeName: 'Query',
+  fieldName: 'getPost',
+});
+```
+
+When queried, the specified state machine receives input as the arguments of `getPost()` e.g.:
+
+```graphql
+query MyQuery {
+  getPost(id: 1)
+}
+```
+
+is transformed to:
+
+```json
+{
+  "id": 1
+}
+```
+
+And the state machine should return the output like below:
+
+```json
+{
+  "id": 1,
+  "title": "Hello world!"
+}
+```
+
+Then, AppSync returns the output as the return type of the query:
+
+```graphql
+{
+  "data": {
+    "getPost": {
+      "id": 1,
+      "title": "Hello world!"
+    }
+  }
+}
+```
+
+## Notes
+
+- The state machine must be EXPRESS type. See [Step Functions document](https://docs.aws.amazon.com/step-functions/latest/dg/concepts-standard-vs-express.html) for more details.
+- Currently, this construct doesn't have a good error handling on the response mapping.
+  - We need to handle the case when the workflow fails because `StartSyncExecution` returns 200. See [Step Functions document](https://docs.aws.amazon.com/step-functions/latest/apireference/API_StartSyncExecution.html).
+
+## Authors
+
+OpsBR Software Technology Inc. Visit our website: [https://opsbr.com](https://opsbr.com)
+
+## License
+
+Apache 2.0