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

# AWS::MediaTailor::PrefetchSchedule RecurringRetrieval
<a name="aws-properties-mediatailor-prefetchschedule-recurringretrieval"></a>

With recurring prefetch, MediaTailor automatically prefetches ads for every avail that occurs during the retrieval window. The following configurations describe the MediaTailor behavior when prefetching ads for a live event.

## Syntax
<a name="aws-properties-mediatailor-prefetchschedule-recurringretrieval-syntax"></a>

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

### JSON
<a name="aws-properties-mediatailor-prefetchschedule-recurringretrieval-syntax.json"></a>

```
{
  "[DelayAfterAvailEndSeconds](#cfn-mediatailor-prefetchschedule-recurringretrieval-delayafteravailendseconds)" : {{Integer}},
  "[DynamicVariables](#cfn-mediatailor-prefetchschedule-recurringretrieval-dynamicvariables)" : {{{{{Key}}: {{Value}}, ...}}},
  "[TrafficShapingRetrievalWindow](#cfn-mediatailor-prefetchschedule-recurringretrieval-trafficshapingretrievalwindow)" : {{TrafficShapingRetrievalWindow}},
  "[TrafficShapingTpsConfiguration](#cfn-mediatailor-prefetchschedule-recurringretrieval-trafficshapingtpsconfiguration)" : {{TrafficShapingTpsConfiguration}},
  "[TrafficShapingType](#cfn-mediatailor-prefetchschedule-recurringretrieval-trafficshapingtype)" : {{String}}
}
```

### YAML
<a name="aws-properties-mediatailor-prefetchschedule-recurringretrieval-syntax.yaml"></a>

```
  [DelayAfterAvailEndSeconds](#cfn-mediatailor-prefetchschedule-recurringretrieval-delayafteravailendseconds): {{Integer}}
  [DynamicVariables](#cfn-mediatailor-prefetchschedule-recurringretrieval-dynamicvariables): {{
    {{Key}}: {{Value}}}}
  [TrafficShapingRetrievalWindow](#cfn-mediatailor-prefetchschedule-recurringretrieval-trafficshapingretrievalwindow): {{
    TrafficShapingRetrievalWindow}}
  [TrafficShapingTpsConfiguration](#cfn-mediatailor-prefetchschedule-recurringretrieval-trafficshapingtpsconfiguration): {{
    TrafficShapingTpsConfiguration}}
  [TrafficShapingType](#cfn-mediatailor-prefetchschedule-recurringretrieval-trafficshapingtype): {{String}}
```

## Properties
<a name="aws-properties-mediatailor-prefetchschedule-recurringretrieval-properties"></a>

`DelayAfterAvailEndSeconds`  <a name="cfn-mediatailor-prefetchschedule-recurringretrieval-delayafteravailendseconds"></a>
The number of seconds that MediaTailor waits after an ad avail before prefetching ads for the next avail. If not set, the default is 0 (no delay).  
*Required*: No  
*Type*: Integer  
*Update requires*: [Replacement](https://docs.amazonaws.cn/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-replacement)

`DynamicVariables`  <a name="cfn-mediatailor-prefetchschedule-recurringretrieval-dynamicvariables"></a>
The dynamic variables to use for substitution during prefetch requests to the ADS.  
*Required*: No  
*Type*: Object of String  
*Pattern*: `.+`  
*Update requires*: [Replacement](https://docs.amazonaws.cn/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-replacement)

`TrafficShapingRetrievalWindow`  <a name="cfn-mediatailor-prefetchschedule-recurringretrieval-trafficshapingretrievalwindow"></a>
The configuration that tells AWS Elemental MediaTailor how many seconds to spread out requests to the ad decision server (ADS). Instead of sending ADS requests for all sessions at the same time, MediaTailor spreads the requests across the amount of time specified in the retrieval window.  
*Required*: No  
*Type*: [TrafficShapingRetrievalWindow](aws-properties-mediatailor-prefetchschedule-trafficshapingretrievalwindow.md)  
*Update requires*: [Replacement](https://docs.amazonaws.cn/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-replacement)

`TrafficShapingTpsConfiguration`  <a name="cfn-mediatailor-prefetchschedule-recurringretrieval-trafficshapingtpsconfiguration"></a>
The configuration for TPS-based traffic shaping. This approach limits requests to the ad decision server (ADS) based on transactions per second and concurrent users.  
*Required*: No  
*Type*: [TrafficShapingTpsConfiguration](aws-properties-mediatailor-prefetchschedule-trafficshapingtpsconfiguration.md)  
*Update requires*: [Replacement](https://docs.amazonaws.cn/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-replacement)

`TrafficShapingType`  <a name="cfn-mediatailor-prefetchschedule-recurringretrieval-trafficshapingtype"></a>
Indicates the type of traffic shaping used to limit the number of requests to the ADS at one time.  
*Required*: No  
*Type*: String  
*Allowed values*: `RETRIEVAL_WINDOW | TPS`  
*Update requires*: [Replacement](https://docs.amazonaws.cn/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-replacement)