# Function
<a name="sam-property-graphqlapi-function"></a>

Configure functions in GraphQL APIs to perform certain operations.

## Syntax
<a name="sam-property-graphqlapi-function-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-function-syntax-yaml"></a>

```
{{LogicalId}}:
  CodeUri: {{String}}
  DataSource: {{String}}
  Description: {{String}}
  Id: {{String}}
  InlineCode: {{String}}
  MaxBatchSize: {{Integer}}
  Name: {{String}}
  Runtime: {{Runtime}}
  Sync: {{[SyncConfig](https://docs.amazonaws.cn/AWSCloudFormation/latest/UserGuide/aws-properties-appsync-functionconfiguration-syncconfig.html)}}
```

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

`CodeUri`  <a name="sam-graphqlapi-function-codeuri"></a>
The function code’s Amazon Simple Storage Service (Amazon S3) URI or path to local folder.  
If you specify a path to a local folder, Amazon CloudFormation requires that the file is first uploaded to Amazon S3 before deployment. You can use the Amazon SAM CLI to facilitate this process. For more information, see [How Amazon SAM uploads local files at deployment](deploy-upload-local-files.md).  
*Type*: String  
*Required*: No  
*Amazon CloudFormation compatibility*: This property is passed directly to the `[CodeS3Location](https://docs.amazonaws.cn/AWSCloudFormation/latest/UserGuide/aws-resource-appsync-functionconfiguration.html#cfn-appsync-functionconfiguration-codes3location)` property of an `AWS::AppSync::FunctionConfiguration` resource.

`DataSource`  <a name="sam-graphqlapi-function-datasource"></a>
The name of the data source that this function will attach to.  
+ To reference a data source within the `AWS::Serverless::GraphQLApi` resource, specify its logical ID.
+ To reference a data source outside of the `AWS::Serverless::GraphQLApi` resource, provide its `Name` attribute using the `Fn::GetAtt` intrinsic function. For example, `!GetAtt MyLambdaDataSource.Name`.
+ To reference a data source from a different stack, use `[Fn::ImportValue](https://docs.amazonaws.cn/AWSCloudFormation/latest/UserGuide/intrinsic-function-reference-importvalue.html)`.
If a variation of `[NONE | None | none]` is specified, Amazon SAM will generate a `None` value for the `AWS::AppSync::DataSource` `[Type](https://docs.amazonaws.cn/AWSCloudFormation/latest/UserGuide/aws-resource-appsync-datasource.html#cfn-appsync-datasource-type)` object.  
*Type*: String  
*Required*: Yes  
*Amazon CloudFormation compatibility*: This property is passed directly to the `[DataSourceName](https://docs.amazonaws.cn/AWSCloudFormation/latest/UserGuide/aws-resource-appsync-functionconfiguration.html#cfn-appsync-functionconfiguration-datasourcename)` property of an `AWS::AppSync::FunctionConfiguration` resource.

`Description`  <a name="sam-graphqlapi-function-description"></a>
The description of your function.  
*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-functionconfiguration.html#cfn-appsync-functionconfiguration-description)` property of an `AWS::AppSync::FunctionConfiguration` resource.

`Id`  <a name="sam-graphqlapi-function-id"></a>
The Function ID for a function located outside of the `AWS::Serverless::GraphQLApi` resource.  
+ To reference a function within the same Amazon SAM template, use the `Fn::GetAtt` intrinsic function. For example `Id: !GetAtt createPostItemFunc.FunctionId`.
+ To reference a function from a different stack, use `[Fn::ImportValue](https://docs.amazonaws.cn/AWSCloudFormation/latest/UserGuide/intrinsic-function-reference-importvalue.html)`.
When using `Id`, all other properties are not allowed. Amazon SAM will automatically pass the Function ID of your referenced function.  
*Type*: String  
*Required*: No  
*Amazon CloudFormation compatibility*: This property is unique to Amazon SAM and doesn’t have an Amazon CloudFormation equivalent.

`InlineCode`  <a name="sam-graphqlapi-function-inlinecode"></a>
The function code that contains the request and response functions.  
*Type*: String  
*Required*: No  
*Amazon CloudFormation compatibility*: This property is passed directly to the `[Code](https://docs.amazonaws.cn/AWSCloudFormation/latest/UserGuide/aws-resource-appsync-functionconfiguration.html#cfn-appsync-functionconfiguration-code)` property of an `AWS::AppSync::FunctionConfiguration` resource.

`LogicalId`  <a name="sam-graphqlapi-function-logicalid"></a>
The unique name of your function.  
*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-functionconfiguration.html#cfn-appsync-functionconfiguration-name)` property of an `AWS::AppSync::FunctionConfiguration` resource.

`MaxBatchSize`  <a name="sam-graphqlapi-function-maxbatchsize"></a>
The maximum number of resolver request inputs that will be sent to a single Amazon Lambda function in a `BatchInvoke` operation.  
*Type*: Integer  
*Required*: No  
*Amazon CloudFormation compatibility*: This property is passed directly to the [MaxBatchSize](https://docs.amazonaws.cn/AWSCloudFormation/latest/UserGuide/aws-resource-appsync-functionconfiguration.html#cfn-appsync-functionconfiguration-maxbatchsize) property of an `AWS::AppSync::FunctionConfiguration` resource.

`Name`  <a name="sam-graphqlapi-function-name"></a>
The name of the function. Specify 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-functionconfiguration.html#cfn-appsync-functionconfiguration-name)` property of an `AWS::AppSync::FunctionConfiguration` resource.

`Runtime`  <a name="sam-graphqlapi-function-runtime"></a>
Describes a runtime used by an Amazon AppSync pipeline resolver or Amazon AppSync function. Specifies the name and version of the runtime to use.  
*Type*: [Runtime](sam-property-graphqlapi-function-runtime.md)  
*Required*: Yes  
*Amazon CloudFormation compatibility*: This property is unique to Amazon SAM and doesn't have an Amazon CloudFormation equivalent. It is similar to the `[Runtime](https://docs.amazonaws.cn/AWSCloudFormation/latest/UserGuide/aws-resource-appsync-functionconfiguration.html#cfn-appsync-functionconfiguration-runtime)` property of an `AWS::AppSync::FunctionConfiguration` resource.

`Sync`  <a name="sam-graphqlapi-function-sync"></a>
Describes a Sync configuration for a function.  
Specifies which Conflict Detection strategy and Resolution strategy to use when the function is invoked.  
*Type*: [SyncConfig](https://docs.amazonaws.cn/AWSCloudFormation/latest/UserGuide/aws-properties-appsync-functionconfiguration-syncconfig.html)  
*Required*: No  
*Amazon CloudFormation compatibility*: This property is passed directly to the `[SyncConfig](https://docs.amazonaws.cn/AWSCloudFormation/latest/UserGuide/aws-resource-appsync-functionconfiguration.html#cfn-appsync-functionconfiguration-syncconfig)` property of an `AWS::AppSync::FunctionConfiguration` resource.