# AWS AppSync JavaScript resolver function reference for EventBridge data source
<a name="resolver-reference-eventbridge-js"></a>

The AWS AppSync resolver function request and response used with the EventBridge data source allows you to send custom events to the Amazon EventBridge bus.

## Request
<a name="request-js"></a>

The request handler allows you to send multiple custom events to an EventBridge event bus:

```
export function request(ctx) {
  return {
    "operation" : "PutEvents",
    "events" : [{}]
  }
}
```

An EventBridge `PutEvents` request has the following type definition:

```
type PutEventsRequest = {
  operation: 'PutEvents'
  events: {
    source: string
    detail: { [key: string]: any }
    detailType: string
    resources?: string[]
    time?: string // RFC3339 Timestamp format
  }[]
}
```

## Response
<a name="response-js"></a>

If the `PutEvents` operation is successful, the response from EventBridge is included in the `ctx.result`:

```
export function response(ctx) {
  if(ctx.error)
    util.error(ctx.error.message, ctx.error.type, ctx.result)
  else
    return ctx.result
}
```

Errors that occur while performing `PutEvents` operations such as `InternalExceptions` or `Timeouts` will appear in `ctx.error`. For a list of EventBridge's common errors, see the [EventBridge common error reference](https://docs.aws.amazon.com/eventbridge/latest/APIReference/CommonErrors.html).

The `result` will have the following type definition:

```
type PutEventsResult = {
  Entries: {
    ErrorCode: string
    ErrorMessage: string
    EventId: string
  }[]
  FailedEntryCount: number
}
```
+ **Entries**

  The ingested event results, both successful and unsuccessful. If the ingestion was successful, the entry has the `EventID` in it. Otherwise, you can use the `ErrorCode` and `ErrorMessage` to identify the problem with the entry.

  For each record, the index of the response element is the same as the index in the request array.
+ **FailedEntryCount**

  The number of failed entries. This value is represented as an integer.

For more information about the response of `PutEvents`, see [PutEvents](https://docs.aws.amazon.com/eventbridge/latest/APIReference/API_PutEvents.html#API_PutEvents_ResponseElements).

**Example sample response 1**

The following example is a `PutEvents` operation with two successful events:

```
{
    "Entries" : [ 
        {
            "EventId": "11710aed-b79e-4468-a20b-bb3c0c3b4860"
        }, 
        {
            "EventId": "d804d26a-88db-4b66-9eaf-9a11c708ae82"
        }
    ],
    "FailedEntryCount" : 0
}
```

**Example sample response 2**

The following example is a `PutEvents` operation with three events, two successes and one fail:

```
{
    "Entries" : [ 
        {
            "EventId": "11710aed-b79e-4468-a20b-bb3c0c3b4860"
        }, 
        {
            "EventId": "d804d26a-88db-4b66-9eaf-9a11c708ae82"
        },
        {
            "ErrorCode" : "SampleErrorCode",
            "ErrorMessage" : "Sample Error Message"
        }
    ],
    "FailedEntryCount" : 1
}
```

## `PutEvents` fields
<a name="putevents-field"></a>

`PutEvents` contains the following mapping template fields:
+ **Version**

  Common to all request mapping templates, the `version` field defines the version that the template uses. This field is required. The value `2018-05-29` is the only version supported for the EventBridge mapping templates.
+ **Operation**

  The only supported operation is `PutEvents`. This operation allows you to add custom events to your event bus.
+ **Events**

  An array of events that will be added to the event bus. This array should have an allocation of 1 - 10 items.

  The `Event` object has the following fields:
  + `"source"`: A string that defines the source of the event.
  + `"detail"`: A JSON object that you can use to attach information about the event. This field can be an empty map ( `{ }` ).
  + `"detailType`: A string that identifies the type of event.
  + `"resources"`: A JSON array of strings that identifies resources involved in the event. This field can be an empty array.
  + `"time"`: The event timestamp provided as a string. This should follow the [RFC3339](https://www.rfc-editor.org/rfc/rfc3339.txt) timestamp format.

The snippets below are some examples of valid `Event` objects:

**Example 1**

```
{
    "source" : "source1",
    "detail" : {
        "key1" : [1,2,3,4],
        "key2" : "strval"
    },
    "detailType" : "sampleDetailType",
    "resources" : ["Resouce1", "Resource2"],
    "time" : "2022-01-10T05:00:10Z"
}
```

**Example 2**

```
{
    "source" : "source1",
    "detail" : {},
    "detailType" : "sampleDetailType"
}
```

**Example 3**

```
{
    "source" : "source1",
    "detail" : {
        "key1" : 1200
    },
    "detailType" : "sampleDetailType",
    "resources" : []
}
```