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::Resolver
<a name="aws-resource-appsync-resolver"></a>

The `AWS::AppSync::Resolver` resource defines the logical GraphQL resolver that you attach to fields in a schema. Request and response templates for resolvers are written in Apache Velocity Template Language (VTL) format. For more information about resolvers, see [Resolver Mapping Template Reference](https://docs.aws.amazon.com/appsync/latest/devguide/resolver-mapping-template-reference.html).

**Note**  
When you submit an update, AWS CloudFormation updates resources based on differences between what you submit and the stack's current template. To cause this resource to be updated you must change a property value for this resource in the CloudFormation template. Changing the Amazon S3 file content without changing a property value will not result in an update operation.  
See [Update Behaviors of Stack Resources](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html) in the *AWS CloudFormation User Guide*.

## Syntax
<a name="aws-resource-appsync-resolver-syntax"></a>

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

### JSON
<a name="aws-resource-appsync-resolver-syntax.json"></a>

```
{
  "Type" : "AWS::AppSync::Resolver",
  "Properties" : {
      "[ApiId](#cfn-appsync-resolver-apiid)" : String,
      "[CachingConfig](#cfn-appsync-resolver-cachingconfig)" : CachingConfig,
      "[Code](#cfn-appsync-resolver-code)" : String,
      "[CodeS3Location](#cfn-appsync-resolver-codes3location)" : String,
      "[DataSourceName](#cfn-appsync-resolver-datasourcename)" : String,
      "[FieldName](#cfn-appsync-resolver-fieldname)" : String,
      "[Kind](#cfn-appsync-resolver-kind)" : String,
      "[MaxBatchSize](#cfn-appsync-resolver-maxbatchsize)" : Integer,
      "[MetricsConfig](#cfn-appsync-resolver-metricsconfig)" : String,
      "[PipelineConfig](#cfn-appsync-resolver-pipelineconfig)" : PipelineConfig,
      "[RequestMappingTemplate](#cfn-appsync-resolver-requestmappingtemplate)" : String,
      "[RequestMappingTemplateS3Location](#cfn-appsync-resolver-requestmappingtemplates3location)" : String,
      "[ResponseMappingTemplate](#cfn-appsync-resolver-responsemappingtemplate)" : String,
      "[ResponseMappingTemplateS3Location](#cfn-appsync-resolver-responsemappingtemplates3location)" : String,
      "[Runtime](#cfn-appsync-resolver-runtime)" : AppSyncRuntime,
      "[SyncConfig](#cfn-appsync-resolver-syncconfig)" : SyncConfig,
      "[TypeName](#cfn-appsync-resolver-typename)" : String
    }
}
```

### YAML
<a name="aws-resource-appsync-resolver-syntax.yaml"></a>

```
Type: AWS::AppSync::Resolver
Properties:
  [ApiId](#cfn-appsync-resolver-apiid): String
  [CachingConfig](#cfn-appsync-resolver-cachingconfig): 
    CachingConfig
  [Code](#cfn-appsync-resolver-code): String
  [CodeS3Location](#cfn-appsync-resolver-codes3location): String
  [DataSourceName](#cfn-appsync-resolver-datasourcename): String
  [FieldName](#cfn-appsync-resolver-fieldname): String
  [Kind](#cfn-appsync-resolver-kind): String
  [MaxBatchSize](#cfn-appsync-resolver-maxbatchsize): Integer
  [MetricsConfig](#cfn-appsync-resolver-metricsconfig): String
  [PipelineConfig](#cfn-appsync-resolver-pipelineconfig): 
    PipelineConfig
  [RequestMappingTemplate](#cfn-appsync-resolver-requestmappingtemplate): String
  [RequestMappingTemplateS3Location](#cfn-appsync-resolver-requestmappingtemplates3location): String
  [ResponseMappingTemplate](#cfn-appsync-resolver-responsemappingtemplate): String
  [ResponseMappingTemplateS3Location](#cfn-appsync-resolver-responsemappingtemplates3location): String
  [Runtime](#cfn-appsync-resolver-runtime): 
    AppSyncRuntime
  [SyncConfig](#cfn-appsync-resolver-syncconfig): 
    SyncConfig
  [TypeName](#cfn-appsync-resolver-typename): String
```

## Properties
<a name="aws-resource-appsync-resolver-properties"></a>

`ApiId`  <a name="cfn-appsync-resolver-apiid"></a>
The AWS AppSync GraphQL API to which you want to attach this resolver.  
*Required*: Yes  
*Type*: String  
*Update requires*: [Replacement](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-replacement)

`CachingConfig`  <a name="cfn-appsync-resolver-cachingconfig"></a>
The caching configuration for the resolver.  
*Required*: No  
*Type*: [CachingConfig](aws-properties-appsync-resolver-cachingconfig.md)  
*Update requires*: [No interruption](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)

`Code`  <a name="cfn-appsync-resolver-code"></a>
The `resolver` code that contains the request and response functions. When code is used, the `runtime` is required. The runtime value must be `APPSYNC_JS`.  
*Required*: No  
*Type*: String  
*Update requires*: [No interruption](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)

`CodeS3Location`  <a name="cfn-appsync-resolver-codes3location"></a>
The Amazon S3 endpoint.  
*Required*: No  
*Type*: String  
*Update requires*: [No interruption](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)

`DataSourceName`  <a name="cfn-appsync-resolver-datasourcename"></a>
The resolver data source name.  
*Required*: No  
*Type*: String  
*Pattern*: `[_A-Za-z][_0-9A-Za-z]*`  
*Minimum*: `1`  
*Maximum*: `65536`  
*Update requires*: [No interruption](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)

`FieldName`  <a name="cfn-appsync-resolver-fieldname"></a>
The GraphQL field on a type that invokes the resolver.   
*Required*: Yes  
*Type*: String  
*Update requires*: [Replacement](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-replacement)

`Kind`  <a name="cfn-appsync-resolver-kind"></a>
The resolver type.  
+ **UNIT**: A UNIT resolver type. A UNIT resolver is the default resolver type. You can use a UNIT resolver to run a GraphQL query against a single data source.
+ **PIPELINE**: A PIPELINE resolver type. You can use a PIPELINE resolver to invoke a series of `Function` objects in a serial manner. You can use a pipeline resolver to run a GraphQL query against multiple data sources.
*Required*: No  
*Type*: String  
*Allowed values*: `UNIT | PIPELINE`  
*Update requires*: [No interruption](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)

`MaxBatchSize`  <a name="cfn-appsync-resolver-maxbatchsize"></a>
The maximum number of resolver request inputs that will be sent to a single AWS Lambda function in a `BatchInvoke` operation.  
*Required*: No  
*Type*: Integer  
*Update requires*: [No interruption](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)

`MetricsConfig`  <a name="cfn-appsync-resolver-metricsconfig"></a>
Enables or disables enhanced resolver metrics for specified resolvers. Note that `MetricsConfig` won't be used unless the `resolverLevelMetricsBehavior` value is set to `PER_RESOLVER_METRICS`. If the `resolverLevelMetricsBehavior` is set to `FULL_REQUEST_RESOLVER_METRICS` instead, `MetricsConfig` will be ignored. However, you can still set its value.  
*Required*: No  
*Type*: String  
*Allowed values*: `ENABLED | DISABLED`  
*Update requires*: [No interruption](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)

`PipelineConfig`  <a name="cfn-appsync-resolver-pipelineconfig"></a>
Functions linked with the pipeline resolver.  
*Required*: No  
*Type*: [PipelineConfig](aws-properties-appsync-resolver-pipelineconfig.md)  
*Update requires*: [No interruption](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)

`RequestMappingTemplate`  <a name="cfn-appsync-resolver-requestmappingtemplate"></a>
The request mapping template.  
Request mapping templates are optional when using a Lambda data source. For all other data sources, a request mapping template is required.  
*Required*: No  
*Type*: String  
*Pattern*: `^.*$`  
*Minimum*: `1`  
*Maximum*: `65536`  
*Update requires*: [No interruption](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)

`RequestMappingTemplateS3Location`  <a name="cfn-appsync-resolver-requestmappingtemplates3location"></a>
The location of a request mapping template in an Amazon S3 bucket. Use this if you want to provision with a template file in Amazon S3 rather than embedding it in your CloudFormation template.  
*Required*: No  
*Type*: String  
*Update requires*: [No interruption](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)

`ResponseMappingTemplate`  <a name="cfn-appsync-resolver-responsemappingtemplate"></a>
The response mapping template.  
*Required*: No  
*Type*: String  
*Pattern*: `^.*$`  
*Minimum*: `1`  
*Maximum*: `65536`  
*Update requires*: [No interruption](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)

`ResponseMappingTemplateS3Location`  <a name="cfn-appsync-resolver-responsemappingtemplates3location"></a>
The location of a response mapping template in an Amazon S3 bucket. Use this if you want to provision with a template file in Amazon S3 rather than embedding it in your CloudFormation template.  
*Required*: No  
*Type*: String  
*Update requires*: [No interruption](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)

`Runtime`  <a name="cfn-appsync-resolver-runtime"></a>
Describes a runtime used by an AWS AppSync resolver or AWS AppSync function. Specifies the name and version of the runtime to use. Note that if a runtime is specified, code must also be specified.  
*Required*: No  
*Type*: [AppSyncRuntime](aws-properties-appsync-resolver-appsyncruntime.md)  
*Update requires*: [No interruption](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)

`SyncConfig`  <a name="cfn-appsync-resolver-syncconfig"></a>
The `SyncConfig` for a resolver attached to a versioned data source.  
*Required*: No  
*Type*: [SyncConfig](aws-properties-appsync-resolver-syncconfig.md)  
*Update requires*: [No interruption](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)

`TypeName`  <a name="cfn-appsync-resolver-typename"></a>
The GraphQL type that invokes this resolver.  
*Required*: Yes  
*Type*: String  
*Update requires*: [Replacement](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-replacement)

## Return values
<a name="aws-resource-appsync-resolver-return-values"></a>

### Ref
<a name="aws-resource-appsync-resolver-return-values-ref"></a>

When you pass the logical ID of an `AWS::AppSync::Resolver` resource to the intrinsic `Ref` function, the function returns the ARN of the Resolver, such as `arn:aws:appsync:us-east-1:123456789012:apis/graphqlapiid/types/typename/resolvers/resolvername`. 

For more information about using the `Ref` function, see [Ref](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/intrinsic-function-reference-ref).

### Fn::GetAtt
<a name="aws-resource-appsync-resolver-return-values-fn--getatt"></a>

`Fn::GetAtt` returns a value for a specified attribute of this type. The following are the available attributes and sample return values. 

For more information about using `Fn::GetAtt`, see [Fn::GetAtt](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/intrinsic-function-reference-getatt). 

#### 
<a name="aws-resource-appsync-resolver-return-values-fn--getatt-fn--getatt"></a>

`FieldName`  <a name="FieldName-fn::getatt"></a>
The GraphQL field on a type that invokes the resolver. 

`ResolverArn`  <a name="ResolverArn-fn::getatt"></a>
ARN of the resolver, such as `arn:aws:appsync:us-east-1:123456789012:apis/graphqlapiid/types/typename/resolvers/resolvername`.

`TypeName`  <a name="TypeName-fn::getatt"></a>
The GraphQL type that invokes this resolver.

## Examples
<a name="aws-resource-appsync-resolver--examples"></a>



### Resolver Creation Example
<a name="aws-resource-appsync-resolver--examples--Resolver_Creation_Example"></a>

The following example creates a resolver and associates it with an existing GraphQL API and a data source by passing the GraphQL API ID and data source name as a parameter. 

#### YAML
<a name="aws-resource-appsync-resolver--examples--Resolver_Creation_Example--yaml"></a>

```
Parameters:
  graphQlApiId:
    Type: String
  dataSourceName:
    Type: String
  fieldName:
    Type: String
  typeName:
    Type: String
  requestMappingTemplateS3LocationInput:
    Type: String
  responseMappingTemplateS3LocationInput:
    Type: String
Resources:
  Resolver:
    Type: AWS::AppSync::Resolver
    Properties:
      ApiId:
	Ref: graphQlApiId
      TypeName:
        Ref: typeName
      FieldName:
        Ref: fieldName
      DataSourceName:
        Ref: dataSourceName
      RequestMappingTemplateS3Location:
        Ref: requestMappingTemplateS3LocationInput
      ResponseMappingTemplateS3Location:
        Ref: responseMappingTemplateS3LocationInput
```

#### JSON
<a name="aws-resource-appsync-resolver--examples--Resolver_Creation_Example--json"></a>

```
{
  "Parameters": {
    "graphQlApiId": {
      "Type": "String"
    },
    "dataSourceName": {
      "Type": "String"
    },
    "fieldName": {
      "Type": "String"
    },
    "typeName": {
      "Type": "String"
    },
    "requestMappingTemplateS3LocationInput": {
      "Type": "String"
    },
    "responseMappingTemplateS3LocationInput": {
      "Type": "String"
    }
  },
  "Resources": {
    "Resolver": {
      "Type": "AWS::AppSync::Resolver",
      "Properties": {
        "ApiId": {
          "Ref": "graphQlApiId"
        },
        "TypeName": {
          "Ref": "typeName"
        },
        "FieldName": {
          "Ref": "fieldName"
        },
        "DataSourceName": {
          "Ref": "dataSourceName"
        },
        "RequestMappingTemplateS3Location": {
          "Ref": "requestMappingTemplateS3LocationInput"
        },
        "ResponseMappingTemplateS3Location": {
          "Ref": "responseMappingTemplateS3LocationInput"
        }
      }
    }
  }
}
```

## See also
<a name="aws-resource-appsync-resolver--seealso"></a>
+ [CreateResolver](https://docs.aws.amazon.com/appsync/latest/APIReference/API_CreateResolver.html) operation in the *AWS AppSync API Reference*.