This is the new *CloudFormation Template Reference Guide*. Please update your bookmarks and links. For help getting started with CloudFormation, see the [AWS CloudFormation User Guide](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/Welcome.html).

# AWS::AppSync::FunctionConfiguration SyncConfig
<a name="aws-properties-appsync-functionconfiguration-syncconfig"></a>

Describes a Sync configuration for a resolver.

Specifies which Conflict Detection strategy and Resolution strategy to use when the resolver is invoked.

## Syntax
<a name="aws-properties-appsync-functionconfiguration-syncconfig-syntax"></a>

To declare this entity in your CloudFormation template, use the following syntax:

### JSON
<a name="aws-properties-appsync-functionconfiguration-syncconfig-syntax.json"></a>

```
{
  "[ConflictDetection](#cfn-appsync-functionconfiguration-syncconfig-conflictdetection)" : String,
  "[ConflictHandler](#cfn-appsync-functionconfiguration-syncconfig-conflicthandler)" : String,
  "[LambdaConflictHandlerConfig](#cfn-appsync-functionconfiguration-syncconfig-lambdaconflicthandlerconfig)" : LambdaConflictHandlerConfig
}
```

### YAML
<a name="aws-properties-appsync-functionconfiguration-syncconfig-syntax.yaml"></a>

```
  [ConflictDetection](#cfn-appsync-functionconfiguration-syncconfig-conflictdetection): String
  [ConflictHandler](#cfn-appsync-functionconfiguration-syncconfig-conflicthandler): String
  [LambdaConflictHandlerConfig](#cfn-appsync-functionconfiguration-syncconfig-lambdaconflicthandlerconfig): 
    LambdaConflictHandlerConfig
```

## Properties
<a name="aws-properties-appsync-functionconfiguration-syncconfig-properties"></a>

`ConflictDetection`  <a name="cfn-appsync-functionconfiguration-syncconfig-conflictdetection"></a>
The Conflict Detection strategy to use.  
+ **VERSION**: Detect conflicts based on object versions for this resolver.
+ **NONE**: Do not detect conflicts when invoking this resolver.
*Required*: Yes  
*Type*: String  
*Allowed values*: `VERSION | NONE`  
*Update requires*: [No interruption](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)

`ConflictHandler`  <a name="cfn-appsync-functionconfiguration-syncconfig-conflicthandler"></a>
The Conflict Resolution strategy to perform in the event of a conflict.  
+ **OPTIMISTIC\$1CONCURRENCY**: Resolve conflicts by rejecting mutations when versions don't match the latest version at the server.
+ **AUTOMERGE**: Resolve conflicts with the Automerge conflict resolution strategy.
+ **LAMBDA**: Resolve conflicts with an AWS Lambda function supplied in the `LambdaConflictHandlerConfig`.
*Required*: No  
*Type*: String  
*Allowed values*: `OPTIMISTIC_CONCURRENCY | LAMBDA | AUTOMERGE | NONE`  
*Update requires*: [No interruption](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)

`LambdaConflictHandlerConfig`  <a name="cfn-appsync-functionconfiguration-syncconfig-lambdaconflicthandlerconfig"></a>
The `LambdaConflictHandlerConfig` when configuring `LAMBDA` as the Conflict Handler.  
*Required*: No  
*Type*: [LambdaConflictHandlerConfig](aws-properties-appsync-functionconfiguration-lambdaconflicthandlerconfig.md)  
*Update requires*: [No interruption](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)