template.yml

AWSTemplateFormatVersion: 2010-09-09
Transform: AWS::Serverless-2016-10-31

Parameters:
  TableName: 
    Type: String
    Description: (Required) The name of the DynamoDB table you want to create and save to. Minimum 3 characters
    MinLength: 3
    MaxLength: 50
    ConstraintDescription: 'Required parameter. Must be characters and/or underscores. No numbers allowed.'
    Default: 'yourDBTableName'
    AllowedPattern: ^[A-Za-z_]+$
  StageEnvironment:
    Type: String
    MinLength: 3
    MaxLength: 15
    Default: 'dev'

Resources:

  AppSyncApi:
    Type: AWS::AppSync::GraphQLApi
    Properties:
      Name: !Sub ${TableName}Api${StageEnvironment}
      AuthenticationType: API_KEY
    
  AppSyncAPIKey:
    Type: AWS::AppSync::ApiKey
    Properties:
      ApiId: !GetAtt AppSyncApi.ApiId
  
  AppSyncSchema:
    Type: AWS::AppSync::GraphQLSchema
    Properties:
      ApiId: !GetAtt AppSyncApi.ApiId
      Definition: !Sub |
        type ${TableName} {
          ${TableName}Id: ID!
          name: String
        }
        type Paginated${TableName} {
          items: [${TableName}!]!
          nextToken: String
        }
        type Query {
          all(limit: Int, nextToken: String): Paginated${TableName}!
          getOne(${TableName}Id: ID!): ${TableName}
        }
        type Mutation {
          save(${TableName}Id: ID!, name: String!): ${TableName}
          delete(${TableName}Id: ID!): ${TableName}
        }
        type Schema {
          query: Query
          mutation: Mutation
        }

  AppSyncTableDataSource:
    Type: AWS::AppSync::DataSource
    Properties:
      ApiId: !GetAtt AppSyncApi.ApiId
      Name: !Ref TableName
      Description: DynamoDB Table AppSync Data Source
      Type: AMAZON_DYNAMODB
      ServiceRoleArn: !GetAtt DynamoDBRole.Arn
      DynamoDBConfig:
        TableName: !Ref DynamoDBTable
        AwsRegion: !Sub ${AWS::Region}

  AppSyncGetOneQueryResolver:
    Type: AWS::AppSync::Resolver
    DependsOn: AppSyncSchema
    Properties:
      ApiId: !GetAtt AppSyncApi.ApiId
      TypeName: Query
      FieldName: getOne
      DataSourceName: !GetAtt AppSyncTableDataSource.Name
      RequestMappingTemplate: !Sub |
        {
          "version": "2017-02-28",
          "operation": "GetItem",
          "key": {
            "${TableName}Id": $util.dynamodb.toDynamoDBJson($ctx.args.${TableName}Id)
          }
        }
      ResponseMappingTemplate: "$util.toJson($ctx.result)"

  AppSyncAllQueryResolver:
    Type: AWS::AppSync::Resolver
    DependsOn: AppSyncSchema
    Properties:
      ApiId: !GetAtt AppSyncApi.ApiId
      TypeName: Query
      FieldName: all
      DataSourceName: !GetAtt AppSyncTableDataSource.Name
      RequestMappingTemplate: !Sub |
        {
          "version": "2017-02-28",
          "operation" : "Scan",
          "limit": $util.defaultIfNull($ctx.args.limit, 20),
          "nextToken": $util.toJson($util.defaultIfNullOrEmpty($ctx.args.nextToken, null))
        },
      ResponseMappingTemplate: "$util.toJson($ctx.result)"

  AppSyncSaveMutationResolver:
    Type: AWS::AppSync::Resolver
    DependsOn: AppSyncSchema
    Properties:
      ApiId: !GetAtt AppSyncApi.ApiId
      TypeName: Mutation
      FieldName: save
      DataSourceName: !GetAtt AppSyncTableDataSource.Name
      RequestMappingTemplate: !Sub |
        {
          "version": "2017-02-28",
          "operation": "PutItem",
          "key": {
            "${TableName}Id": $util.dynamodb.toDynamoDBJson($ctx.args.${TableName}Id)
          },
          "attributeValues": {
            "name": $util.dynamodb.toDynamoDBJson($ctx.args.name)
          }
        }
      ResponseMappingTemplate: "$util.toJson($ctx.result)"

  AppSyncDeleteMutationResolver:
    Type: AWS::AppSync::Resolver
    DependsOn: AppSyncSchema
    Properties:
      ApiId: !GetAtt AppSyncApi.ApiId
      TypeName: Mutation
      FieldName: delete
      DataSourceName: !GetAtt AppSyncTableDataSource.Name
      RequestMappingTemplate: !Sub |
        {
          "version": "2017-02-28",
          "operation": "DeleteItem",
          "key": {
            "${TableName}Id": $util.dynamodb.toDynamoDBJson($ctx.args.${TableName}Id)
          }
        }
      ResponseMappingTemplate: "$util.toJson($ctx.result)"

  DynamoDBRole:
    Type: AWS::IAM::Role
    Properties:
      RoleName: !Sub ${TableName}-appsync-dynamodb-role
      ManagedPolicyArns:
        - arn:aws:iam::aws:policy/AmazonDynamoDBFullAccess
      AssumeRolePolicyDocument:
        Version: 2012-10-17
        Statement:
          - Effect: Allow
            Action:
              - sts:AssumeRole
            Principal:
              Service:
                - appsync.amazonaws.com

  DynamoDBTable:
    Type: AWS::DynamoDB::Table
    Properties:
      TableName: !Ref TableName
      AttributeDefinitions:
        -
          AttributeName: !Sub ${TableName}Id
          AttributeType: S
      KeySchema:
        -
          AttributeName: !Sub ${TableName}Id
          KeyType: HASH
      ProvisionedThroughput:
        ReadCapacityUnits: 5
        WriteCapacityUnits: 5
      StreamSpecification:
        StreamViewType: NEW_IMAGE

Outputs:  
  DynamoDBTable:
    Description: The name of the DynamoDB Table
    Value: !Ref DynamoDBTable
  GraphQLApiEndpoint:
    Description: The URL to the GraphQL Endpoint
    Value: !GetAtt AppSyncApi.GraphQLUrl
  GraphQLApiId:
    Description: The API ID of the GraphQL API
    Value: !GetAtt AppSyncApi.ApiId
  APIKey:
    Description: API Key
    Value: !GetAtt AppSyncAPIKey.ApiKey