template.yaml

AWSTemplateFormatVersion: '2010-09-09'
Transform: AWS::Serverless-2016-10-31
Description: >
  Sample code for AWS blog post "Building a GraphQL interface to Amazon QLDB with AWS AppSync"

Globals:
  Function:
    Timeout: 20

Resources:
  ## QLDB ##
  QldbLedger:
    Type: AWS::QLDB::Ledger
    Properties:
      DeletionProtection: false
      Name: vehicle-registration
      PermissionsMode: ALLOW_ALL

  ## Lambda ##
  # Lambda function to integrate QLDB and AppSync
  QLDBIntegrationFunction:
    Type: AWS::Serverless::Function
    Properties:
      CodeUri: QLDBIntegrationFunction
      Handler: qldb.App::handleRequest
      Runtime: java11
      MemorySize: 512
      Tracing: Active
      Environment:
        Variables:
          QLDB_LEDGER: !Ref QldbLedger
      Policies:
        - Version: "2012-10-17"
          Statement:
            - Effect: Allow 
              Action:
                - qldb:ExecuteStatement
                - qldb:GetRevision
                - qldb:SendCommand
              Resource: !Sub "arn:aws:qldb:${AWS::Region}:${AWS::AccountId}:ledger/${QldbLedger}"

  # For more information, see https://github.com/aws-cloudformation/custom-resource-helper
  LoadSampleDataResourceFunction:
    Type: AWS::Serverless::Function
    Properties:
      CodeUri: LoadSampleDataResource
      Handler: custom_resource.handler
      Runtime: python3.7
      Timeout: 300
      Policies:
        - Version: "2012-10-17"
          Statement:
            - Effect: Allow
              Action:
                - qldb:ExecuteStatement
                - qldb:GetRevision
                - qldb:SendCommand
              Resource: !Sub "arn:aws:qldb:${AWS::Region}:${AWS::AccountId}:ledger/${QldbLedger}"

  LoadSampleDataResource:
    Type: Custom::LoadSampleData
    Properties:
      QldbLedger: !Ref QldbLedger
      ServiceToken: !GetAtt LoadSampleDataResourceFunction.Arn

  ## AppSync ##
  DmvApi:
    Type: AWS::AppSync::GraphQLApi
    Properties:
      AuthenticationType: API_KEY
      Name: DMVApi
      XrayEnabled: true
#      LogConfig:
#        CloudWatchLogsRoleArn: !GetAtt AppSyncServiceRole.Arn
#        FieldLogLevel: "ALL"

  DmvApiKey:
    Type: AWS::AppSync::ApiKey
    Properties:
      ApiId: !GetAtt DmvApi.ApiId
      Description: API Key for DMV API

  DmvSchema:
    Type: AWS::AppSync::GraphQLSchema
    Properties:
      ApiId: !GetAtt DmvApi.ApiId
      DefinitionS3Location: schema.graphql

  ## AppSync -- Queries ##
  GetVehicleQueryResolver:
    Type: AWS::AppSync::Resolver
    Properties:
      ApiId: !GetAtt DmvApi.ApiId
      TypeName: Query
      FieldName: getVehicle
      DataSourceName: !GetAtt QLDBIntegrationDataSource.Name
      RequestMappingTemplate: |
        {
          "version": "2017-02-28",
          "operation": "Invoke",
          "payload": {
            "action": "Query",
            "payload": [
              {
                "query": "SELECT * FROM Vehicle AS t WHERE t.VIN = ?",
                "args": [ "$ctx.args.vin" ]
              }
            ]
          }
        }
      ResponseMappingTemplate: |
        #if ($ctx.result.error)
          $utils.error($ctx.result.error)
        #else
          #set( $result = $util.parseJson($ctx.result.result) )
          $util.toJson($result[0])
        #end

  GetVehicleRegistrationQueryResolver:
    Type: AWS::AppSync::Resolver
    Properties:
      ApiId: !GetAtt DmvApi.ApiId
      TypeName: Query
      FieldName: getVehicleRegistration
      DataSourceName: !GetAtt QLDBIntegrationDataSource.Name
      RequestMappingTemplate: |
        {
          "version": "2017-02-28",
          "operation": "Invoke",
          "payload": {
            "action": "Query",
            "payload": [
              {
                "query": "SELECT * FROM VehicleRegistration AS t WHERE t.VIN = ?",
                "args": [ "$ctx.args.vin" ]
              }
            ]
          }
        }
      ResponseMappingTemplate: |
        #if ($ctx.result.error)
          $utils.error($ctx.result.error)
        #else
          #set( $result = $util.parseJson($ctx.result.result) )
          $util.toJson($result[0])
        #end

  GetPersonQueryResolver:
    Type: AWS::AppSync::Resolver
    Properties:
      ApiId: !GetAtt DmvApi.ApiId
      TypeName: Query
      FieldName: getPerson
      DataSourceName: !GetAtt QLDBIntegrationDataSource.Name
      RequestMappingTemplate: |
        {
          "version": "2017-02-28",
          "operation": "Invoke",
          "payload": {
            "action": "Query",
            "payload": [
              {
                "query": "SELECT * FROM Person AS t WHERE t.GovId = ?",
                "args": [ "$ctx.args.govId" ]
              }
            ]
          }
        }
      ResponseMappingTemplate: |
        #if ($ctx.result.error)
          $utils.error($ctx.result.error)
        #else
          #set( $result = $util.parseJson($ctx.result.result) )
          $util.toJson($result[0])
        #end

  OwnersFieldResolver:
    Type: AWS::AppSync::Resolver
    Properties:
      ApiId: !GetAtt DmvApi.ApiId
      TypeName: Owners
      FieldName: PrimaryOwner
      DataSourceName: !GetAtt QLDBIntegrationDataSource.Name
      RequestMappingTemplate: |
        {
          "version": "2017-02-28",
          "operation": "Invoke",
          "payload": {
            "action": "Query",
            "payload": [
              {
                "query": "SELECT * FROM Person as p BY pid WHERE pid = ?",
                "args": [ "$ctx.source.PrimaryOwner.PersonId" ]
              }
            ]
          }
        }
      ResponseMappingTemplate: |
        #if ($ctx.result.error)
          $utils.error($ctx.result.error)
        #else
          #set( $result = $util.parseJson($ctx.result.result) )
          $util.toJson($result[0])
        #end

  OwnersSecondaryOwnersFieldResolver:
    Type: AWS::AppSync::Resolver
    Properties:
      ApiId: !GetAtt DmvApi.ApiId
      TypeName: Owners
      FieldName: SecondaryOwners
      DataSourceName: !GetAtt QLDBIntegrationDataSource.Name
      RequestMappingTemplate: |
        {
          "version": "2017-02-28",
          "operation": "Invoke",
          "payload": {
            "action": "Query",
            "payload": [
              {
                "query": "SELECT * FROM Person as p BY pid WHERE pid IN ?",
                "args": [ "$ctx.source.SecondaryOwners" ]
              }
            ]
          }
        }
      ResponseMappingTemplate: |
        #set( $result = $util.parseJson($ctx.result.result) )
        $util.toJson($result)

  VehiclesByOwnerQueryResolver:
    Type: AWS::AppSync::Resolver
    Properties:
      ApiId: !GetAtt DmvApi.ApiId
      TypeName: Query
      FieldName: vehiclesByOwner
      DataSourceName: !GetAtt QLDBIntegrationDataSource.Name
      RequestMappingTemplate: |
        {
          "version": "2017-02-28",
          "operation": "Invoke",
          "payload": {
            "action": "Query",
            "payload": [
              {
                "query": "SELECT id FROM Person AS t BY id WHERE t.GovId = ?",
                "args": [ "$ctx.args.govId" ]
              },
              {
                "query": "SELECT Vehicle FROM Vehicle INNER JOIN VehicleRegistration AS r ON Vehicle.VIN = r.VIN WHERE r.Owners.PrimaryOwner.PersonId = ?",
                "args": [ "$.[0].id" ]
              }
            ]
          }
        }
      ResponseMappingTemplate: |
        #if ($ctx.result.error)
          $utils.error($ctx.result.error)
        #end

        #set( $vehicles = $util.parseJson($ctx.result.result) )
        #set( $result = [] )
        #foreach($v in $vehicles)
          $util.qr($result.add($v.Vehicle))
        #end
        $util.toJson($result)

  GetOwnershipHistoryQueryResolver:
    Type: AWS::AppSync::Resolver
    Properties:
      ApiId: !GetAtt DmvApi.ApiId
      TypeName: Query
      FieldName: getOwnershipHistory
      DataSourceName: !GetAtt QLDBIntegrationDataSource.Name
      RequestMappingTemplate: |
        #set( $months = $util.defaultIfNull($ctx.args.monthsAgo, 3) )
        #set( $currEpochTime = $util.time.nowEpochMilliSeconds() )
        #set( $fromEpochTime = $currEpochTime - ($months * 30 * 24 * 60 * 60 * 1000) )
        #set( $fromTime = $util.time.epochMilliSecondsToISO8601($fromEpochTime) )
        {
          "version": "2017-02-28",
          "operation": "Invoke",
          "payload": {
            "action": "Query",
            "payload": [
              {
                "query": "SELECT id FROM VehicleRegistration AS t BY id WHERE t.VIN = ?",
                "args": [ "$ctx.args.vin" ]
              },
              {
                "query": "SELECT * FROM history(VehicleRegistration, `$fromTime`) AS h WHERE h.metadata.id = ?",
                "args": [ "$.[0].id" ]
              }
            ]
          }
        }
      ResponseMappingTemplate: |
        #if ($ctx.result.error)
          $utils.error($ctx.result.error)
        #end

        #set( $result = $util.parseJson($ctx.result.result) )
        #set( $history = [] )

        #foreach($item in $result)
          #set( $data = $item.data )
          ## Need to set the type of each history item ... could try to make this more dynamic
          $util.qr($data.put("__typename", "VehicleRegistration"))
          #set( $h = {
            "id": "$item.metadata.id",
            "version": $item.metadata.version,
            "txTime": "$item.metadata.txTime",
            "txId": "$item.metadata.txId",
            "hash": "$item.hash",
            "data": $data
          } )
          $util.qr($history.add($h))
        #end
        $util.toJson($history)


  ## AppSync -- Mutations ##
  UpdateVehicleOwnerMutation:
    Type: AWS::AppSync::Resolver
    Properties:
      ApiId: !GetAtt DmvApi.ApiId
      TypeName: Mutation
      FieldName: updateVehicleOwner
      DataSourceName: !GetAtt QLDBIntegrationDataSource.Name
      RequestMappingTemplate: |
        {
          "version": "2017-02-28",
          "operation": "Invoke",
          "payload": {
            "action": "Query",
            "payload": [
              {
                "query": "SELECT id FROM Person AS t BY id WHERE t.GovId = ?",
                "args": [ "$ctx.args.govId" ]
              },
              {
                "query": "UPDATE VehicleRegistration AS v SET v.Owners.PrimaryOwner.PersonId = ? WHERE v.VIN = ?",
                "args": [ "$.[0].id", "$ctx.args.vin" ]
              }
            ]
          }
        }
      ResponseMappingTemplate: |
        #if ($ctx.result.error)
          $utils.error($ctx.result.error)
        #else
          $util.toJson($ctx.result.success)
        #end

  AddSecondaryOwnerMutation:
    Type: AWS::AppSync::Resolver
    Properties:
      ApiId: !GetAtt DmvApi.ApiId
      TypeName: Mutation
      FieldName: addSecondaryOwner
      DataSourceName: !GetAtt QLDBIntegrationDataSource.Name
      RequestMappingTemplate: |
        {
          "version": "2017-02-28",
          "operation": "Invoke",
          "payload": {
            "action": "Query",
            "payload": [
              {
                "query": "SELECT id FROM Person AS t BY id WHERE t.GovId = ?",
                "args": [ "$ctx.args.govId" ]
              },
              {
                "query": "FROM VehicleRegistration AS v WHERE v.VIN = ? INSERT INTO v.Owners.SecondaryOwners VALUE ?",
                "args": [ "$ctx.args.vin", "$.[0].id" ]
              }
            ]
          }
        }
      ResponseMappingTemplate: |
        #if ($ctx.result.error)
          $utils.error($ctx.result.error)
        #else
          $util.toJson($ctx.result.success)
        #end

  ## AppSync -- Pipeline Resolver Functions ##
  GetDocumentByIdFunction:
    Type: AWS::AppSync::FunctionConfiguration
    Properties:
      ApiId: !GetAtt DmvApi.ApiId
      Name: GetDocumentById
      Description: Get the document ID of a particular QLDB document.
      DataSourceName: !GetAtt QLDBIntegrationDataSource.Name
      FunctionVersion: "2018-05-29"
      RequestMappingTemplate: |
        {
          "version": "2017-02-28",
          "operation": "Invoke",
          "payload": {
            "action": "Query",
            "payload": [
              {
                "query": "SELECT id FROM $ctx.args.tableName AS t BY id WHERE t.$ctx.args.fieldName = ?",
                "args": [ "$ctx.args.id" ]
              }
            ]
          }
        }
      ResponseMappingTemplate: |
        #set($result = $util.parseJson($ctx.result.result))
        $util.toJson($result[0].id)


  ## AppSync -- Data Sources ##
  QLDBIntegrationDataSource:
    Type: AWS::AppSync::DataSource
    Properties:
      ApiId: !GetAtt DmvApi.ApiId
      Name: QldbIntegration
      Description: Lambda function to integrate with QLDB
      Type: AWS_LAMBDA
      ServiceRoleArn: !GetAtt AppSyncServiceRole.Arn
      LambdaConfig:
        LambdaFunctionArn: !GetAtt QLDBIntegrationFunction.Arn

  AppSyncServiceRole:
    Type: AWS::IAM::Role
    Properties:
      ManagedPolicyArns:
        - arn:aws:iam::aws:policy/service-role/AWSAppSyncPushToCloudWatchLogs
        - arn:aws:iam::aws:policy/AWSXrayWriteOnlyAccess
      AssumeRolePolicyDocument:
        Version: "2012-10-17"
        Statement:
          - Effect: Allow
            Action:
              - sts:AssumeRole
            Principal:
              Service:
                - appsync.amazonaws.com
      Policies:
        - PolicyName: aws-appsync-qldb-integration-policy
          PolicyDocument:
            Version: "2012-10-17"
            Statement:
              - Effect: Allow
                Action:
                  - lambda:InvokeFunction
                Resource:
                  - !GetAtt QLDBIntegrationFunction.Arn

Outputs:
  ApiEndpoint:
    Description: AppSync API Endpoint
    Value: !GetAtt DmvApi.GraphQLUrl

  ApiKey:
    Description: AppSync API Key
    Value: !GetAtt DmvApiKey.ApiKey