# CreateSamplingRule
<a name="API_CreateSamplingRule"></a>

Creates a rule to control sampling behavior for instrumented applications. Services retrieve rules with [GetSamplingRules](https://docs.aws.amazon.com/xray/latest/api/API_GetSamplingRules.html), and evaluate each rule in ascending order of *priority* for each request. If a rule matches, the service records a trace, borrowing it from the reservoir size. After 10 seconds, the service reports back to X-Ray with [GetSamplingTargets](https://docs.aws.amazon.com/xray/latest/api/API_GetSamplingTargets.html) to get updated versions of each in-use rule. The updated rule contains a trace quota that the service can use instead of borrowing from the reservoir.

## Request Syntax
<a name="API_CreateSamplingRule_RequestSyntax"></a>

```
POST /CreateSamplingRule HTTP/1.1
Content-type: application/json

{
   "SamplingRule": { 
      "Attributes": { 
         "string" : "string" 
      },
      "FixedRate": number,
      "Host": "string",
      "HTTPMethod": "string",
      "Priority": number,
      "ReservoirSize": number,
      "ResourceARN": "string",
      "RuleARN": "string",
      "RuleName": "string",
      "SamplingRateBoost": { 
         "CooldownWindowMinutes": number,
         "MaxRate": number
      },
      "ServiceName": "string",
      "ServiceType": "string",
      "URLPath": "string",
      "Version": number
   },
   "Tags": [ 
      { 
         "Key": "string",
         "Value": "string"
      }
   ]
}
```

## URI Request Parameters
<a name="API_CreateSamplingRule_RequestParameters"></a>

The request does not use any URI parameters.

## Request Body
<a name="API_CreateSamplingRule_RequestBody"></a>

The request accepts the following data in JSON format.

 ** [SamplingRule](#API_CreateSamplingRule_RequestSyntax) **   <a name="xray-CreateSamplingRule-request-SamplingRule"></a>
The rule definition.  
Type: [SamplingRule](API_SamplingRule.md) object  
Required: Yes

 ** [Tags](#API_CreateSamplingRule_RequestSyntax) **   <a name="xray-CreateSamplingRule-request-Tags"></a>
A map that contains one or more tag keys and tag values to attach to an X-Ray sampling rule. For more information about ways to use tags, see [Tagging AWS resources](https://docs.aws.amazon.com/general/latest/gr/aws_tagging.html) in the * AWS General Reference*.  
The following restrictions apply to tags:  
+ Maximum number of user-applied tags per resource: 50
+ Maximum tag key length: 128 Unicode characters
+ Maximum tag value length: 256 Unicode characters
+ Valid values for key and value: a-z, A-Z, 0-9, space, and the following characters: \$1 . : / = \$1 - and @
+ Tag keys and values are case sensitive.
+ Don't use `aws:` as a prefix for keys; it's reserved for AWS use.
Type: Array of [Tag](API_Tag.md) objects  
Array Members: Minimum number of 0 items. Maximum number of 200 items.  
Required: No

## Response Syntax
<a name="API_CreateSamplingRule_ResponseSyntax"></a>

```
HTTP/1.1 200
Content-type: application/json

{
   "SamplingRuleRecord": { 
      "CreatedAt": number,
      "ModifiedAt": number,
      "SamplingRule": { 
         "Attributes": { 
            "string" : "string" 
         },
         "FixedRate": number,
         "Host": "string",
         "HTTPMethod": "string",
         "Priority": number,
         "ReservoirSize": number,
         "ResourceARN": "string",
         "RuleARN": "string",
         "RuleName": "string",
         "SamplingRateBoost": { 
            "CooldownWindowMinutes": number,
            "MaxRate": number
         },
         "ServiceName": "string",
         "ServiceType": "string",
         "URLPath": "string",
         "Version": number
      }
   }
}
```

## Response Elements
<a name="API_CreateSamplingRule_ResponseElements"></a>

If the action is successful, the service sends back an HTTP 200 response.

The following data is returned in JSON format by the service.

 ** [SamplingRuleRecord](#API_CreateSamplingRule_ResponseSyntax) **   <a name="xray-CreateSamplingRule-response-SamplingRuleRecord"></a>
The saved rule definition and metadata.  
Type: [SamplingRuleRecord](API_SamplingRuleRecord.md) object

## Errors
<a name="API_CreateSamplingRule_Errors"></a>

For information about the errors that are common to all actions, see [Common Error Types](CommonErrors.md).

 ** InvalidRequestException **   
The request is missing required parameters or has invalid parameters.  
HTTP Status Code: 400

 ** RuleLimitExceededException **   
You have reached the maximum number of sampling rules.  
HTTP Status Code: 400

 ** ThrottledException **   
The request exceeds the maximum number of requests per second.  
HTTP Status Code: 429

## See Also
<a name="API_CreateSamplingRule_SeeAlso"></a>

For more information about using this API in one of the language-specific AWS SDKs, see the following:
+  [AWS Command Line Interface V2](https://docs.aws.amazon.com/goto/cli2/xray-2016-04-12/CreateSamplingRule) 
+  [AWS SDK for .NET V4](https://docs.aws.amazon.com/goto/DotNetSDKV4/xray-2016-04-12/CreateSamplingRule) 
+  [AWS SDK for C\$1\$1](https://docs.aws.amazon.com/goto/SdkForCpp/xray-2016-04-12/CreateSamplingRule) 
+  [AWS SDK for Go v2](https://docs.aws.amazon.com/goto/SdkForGoV2/xray-2016-04-12/CreateSamplingRule) 
+  [AWS SDK for Java V2](https://docs.aws.amazon.com/goto/SdkForJavaV2/xray-2016-04-12/CreateSamplingRule) 
+  [AWS SDK for JavaScript V3](https://docs.aws.amazon.com/goto/SdkForJavaScriptV3/xray-2016-04-12/CreateSamplingRule) 
+  [AWS SDK for Kotlin](https://docs.aws.amazon.com/goto/SdkForKotlin/xray-2016-04-12/CreateSamplingRule) 
+  [AWS SDK for PHP V3](https://docs.aws.amazon.com/goto/SdkForPHPV3/xray-2016-04-12/CreateSamplingRule) 
+  [AWS SDK for Python](https://docs.aws.amazon.com/goto/boto3/xray-2016-04-12/CreateSamplingRule) 
+  [AWS SDK for Ruby V3](https://docs.aws.amazon.com/goto/SdkForRubyV3/xray-2016-04-12/CreateSamplingRule)