# Lambda
<a name="sam-property-graphqlapi-datasource-lambda"></a>

Configure an Amazon Lambda function as a data source for your GraphQL API resolver.

## Syntax
<a name="sam-property-graphqlapi-datasource-lambda-syntax"></a>

To declare this entity in your Amazon Serverless Application Model (Amazon SAM) template, use the following syntax.

### YAML
<a name="sam-property-graphqlapi-datasource-lambda-syntax-yaml"></a>

```
{{LogicalId}}:
  Description: {{String}}
  FunctionArn: {{String}}
  Name: {{String}}
  ServiceRoleArn: {{String}}
```

## Properties
<a name="sam-property-graphqlapi-datasource-lambda-properties"></a>

`Description`  <a name="sam-graphqlapi-datasource-lambda-description"></a>
The description of your data source.  
*Type*: String  
*Required*: No  
*Amazon CloudFormation compatibility*: This property is passed directly to the `[Description](https://docs.amazonaws.cn/AWSCloudFormation/latest/UserGuide/aws-resource-appsync-datasource.html#cfn-appsync-datasource-description)` property of an `AWS::AppSync::DataSource` resource.

`FunctionArn`  <a name="sam-graphqlapi-datasource-lambda-functionarn"></a>
The ARN for the Lambda function.  
*Type*: String  
*Required*: No  
*Amazon CloudFormation compatibility*: This property is passed directly to the `[LambdaFunctionArn](https://docs.amazonaws.cn/AWSCloudFormation/latest/UserGuide/aws-properties-appsync-datasource-lambdaconfig.html#cfn-appsync-datasource-lambdaconfig-lambdafunctionarn)` property of an `AWS::AppSync::DataSource LambdaConfig` object.

`LogicalId`  <a name="sam-graphqlapi-datasource-lambda-logicalid"></a>
The unique name of your data source.  
*Type*: String  
*Required*: Yes  
*Amazon CloudFormation compatibility*: This property is passed directly to the `[Name](https://docs.amazonaws.cn/AWSCloudFormation/latest/UserGuide/aws-resource-appsync-datasource.html#cfn-appsync-datasource-name)` property of an `AWS::AppSync::DataSource` resource.

`Name`  <a name="sam-graphqlapi-datasource-lambda-name"></a>
The name of your data source. Specify this property to override the `LogicalId` value.  
*Type*: String  
*Required*: No  
*Amazon CloudFormation compatibility*: This property is passed directly to the `[Name](https://docs.amazonaws.cn/AWSCloudFormation/latest/UserGuide/aws-resource-appsync-datasource.html#cfn-appsync-datasource-name)` property of an `AWS::AppSync::DataSource` resource.

`ServiceRoleArn`  <a name="sam-graphqlapi-datasource-lambda-servicerolearn"></a>
The Amazon Identity and Access Management (IAM) service role ARN for the data source. The system assumes this role when accessing the data source.  
To revoke access to your data source, remove the Lambda object from your Amazon SAM template.
*Type*: String  
*Required*: No. If not specified, Amazon SAM will provision `Write` permissions using [Amazon SAM connectors](managing-permissions-connectors.md).  
*Amazon CloudFormation compatibility*: This property is passed directly to the `[ServiceRoleArn](https://docs.amazonaws.cn/AWSCloudFormation/latest/UserGuide/aws-resource-appsync-datasource.html#cfn-appsync-datasource-servicerolearn)` property of an `AWS::AppSync::DataSource` resource.