# EventParameters
<a name="API_EventParameters"></a>

 **[Event-based policies only]** Specifies an event that activates an event-based policy.

## Contents
<a name="API_EventParameters_Contents"></a>

 ** DescriptionRegex **   <a name="dlm-Type-EventParameters-DescriptionRegex"></a>
The snapshot description that can trigger the policy. The description pattern is specified using a regular expression. The policy runs only if a snapshot with a description that matches the specified pattern is shared with your account.  
For example, specifying `^.*Created for policy: policy-1234567890abcdef0.*$` configures the policy to run only if snapshots created by policy `policy-1234567890abcdef0` are shared with your account.  
Type: String  
Length Constraints: Minimum length of 0. Maximum length of 1000.  
Pattern: `[\p{all}]*`   
Required: Yes

 ** EventType **   <a name="dlm-Type-EventParameters-EventType"></a>
The type of event. Currently, only snapshot sharing events are supported.  
Type: String  
Valid Values: `shareSnapshot`   
Required: Yes

 ** SnapshotOwner **   <a name="dlm-Type-EventParameters-SnapshotOwner"></a>
The IDs of the AWS accounts that can trigger policy by sharing snapshots with your account. The policy only runs if one of the specified AWS accounts shares a snapshot with your account.  
Type: Array of strings  
Array Members: Minimum number of 0 items. Maximum number of 50 items.  
Length Constraints: Fixed length of 12.  
Pattern: `^[0-9]{12}$`   
Required: Yes

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

For more information about using this API in one of the language-specific AWS SDKs, see the following:
+  [AWS SDK for C\$1\$1](https://docs.aws.amazon.com/goto/SdkForCpp/dlm-2018-01-12/EventParameters) 
+  [AWS SDK for Java V2](https://docs.aws.amazon.com/goto/SdkForJavaV2/dlm-2018-01-12/EventParameters) 
+  [AWS SDK for Ruby V3](https://docs.aws.amazon.com/goto/SdkForRubyV3/dlm-2018-01-12/EventParameters)