JavaScript resolver function reference for EventBridge data source - Amazon AppSync
RequestResponsePutEvents field
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JavaScript resolver function reference for EventBridge data source

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

Request

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

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.

The result will have the following type definition:

type PutEventsResult = {
  Entries: {
    ErrorCode: string
    ErrorMessage: string
    EventId: string
  }[]
  FailedEntry: 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.

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 field

  • 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 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" : []
}