How to use id and eventTime default values in custom event grid topic?

Question

How to use id and eventTime default values in custom event grid topic?

JR 0

I am trying to understand how the highlighted statement works when creating custom event grid topic.

IdandEventTimeNotMapped

According to the description, a value will be generated if you do not put any mapping in id or eventTime. Presumably, it should be the default value assigned but when I publish the following json data, It does not generate any id or eventTime.

Test Data:
[{
	"subject":"TestSubject",
	"topic":"TestTopic",
	"eventType":"TestEventType",
	"dataVersion":"",
	"metadataVersion":"",
	"data":
		{"test":"test"}
}]

Publish Output:
[{
	\"subject\":\"TestSubject\",
	\"topic\":\"TestTopic\",
	\"eventType\":\"TestEventType\",
	\"dataVersion\":\"\",
	\"metadataVersion\":\"\",
	\"data\":
		{\"test\":\"test\"}
}]


Test Data with Id and eventTime:
[{
	"id":null,
	"subject":"TestSubject",
	"topic":"TestTopic",
	"eventType":"TestEventType",
	"eventTime":null,
	"dataVersion":"",
	"metadataVersion":"",
	"data":
		{"test":"test"}
}]

Publish Output 2:
[{\"id\":null,
\"subject\":\"TestSubject\",
\"topic\":\"TestTopic\",
\"eventType\":\"TestEventType\",
\"eventTime\":null,
\"dataVersion\":\"\",
\"metadataVersion\":\"\",
\"data\":{\"test\":\"test\"}}]

MayankBargali-MSFT 70,986 Reputation points Moderator

2023-01-27T05:13:43.6966667+00:00

Hi @JR

Following up to see if Roman answer clears things up. Do let us know if you have any queries.

Please 'Accept as answer' and ‘Upvote’ if it helped so that it can help others in the community looking for help on similar topics.

1 answer

Your answer

MayankBargali-MSFT 70,986 Reputation points Moderator

2023-01-27T05:13:43.6966667+00:00

Hi @JR

Following up to see if Roman answer clears things up. Do let us know if you have any queries.

Please 'Accept as answer' and ‘Upvote’ if it helped so that it can help others in the community looking for help on similar topics.

Answer 1

Roman Kiss 2,246

Hi,

The custom input schema mapping allows to map the properties like is shown on the following screen snippet:

customtopic

Note, that the properties id and eventTime cannot have a default value explicitly like it is possible for other ones. In the case, when the value of that properties is null (included their mapped fields), the value will be generated by AEG.

The following examples show a usage of the above custom input schema with EventGridSchema output:

Input_1:

[  
 {
    "data":{
      "make":"Ducati",
      "model":"Monster"
    }
  }
]

Output_1:

{
  "id":"3cd673e8-062a-4302-b0f6-85d0a61abe3b",
  "eventTime":"2023-01-25T07:19:55.2640365Z",
  "eventType":"myDefaultEventType",
  "dataVersion":"myDefaultDataVersion",
  "metadataVersion":"1",
  "topic":"############",
  "subject":"myDefaultSubject",
  "data":{
    "data":{
      "make":"Ducati",
      "model":"Monster"
    }
  }
}

Input_2:

[
  {
    "myId":"1234567890",
    "data":{
      "make":"Ducati",
      "model":"Monster"
    }
  }
]

Output_2:

{
  "id":"1234567890",
  "eventTime":"2023-01-25T07:29:28.6468959Z",
  "eventType":"myDefaultEventType",
  "dataVersion":"myDefaultDataVersion",
  "metadataVersion":"1",
  "topic":"##################",
  "subject":"myDefaultSubject",
  "data":{
    "myId":"1234567890",
    "data":{
      "make":"Ducati",
      "model":"Monster"
    }
  }
}

Input_3:

[
  {
    "myId":null,
    "data":{
      "make":"Ducati",
      "model":"Monster"
    }
  }
]

Output_3:

{
  "id":"a3592f1d-e4e9-4b21-b295-5efa33dacdc3",
  "eventTime":"2023-01-25T07:31:35.3012037Z",
  "eventType":"myDefaultEventType",
  "dataVersion":"myDefaultDataVersion",
  "metadataVersion":"1",
  "topic":"##################",
  "subject":"myDefaultSubject",
  "data":{
    "myId":null,
    "data":{
      "make":"Ducati",
      "model":"Monster"
    }
  }
}

Thanks

Roman

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JReyes 5 Reputation points

2023-01-30T21:02:41.3866667+00:00
Thanks for the comment @Roman Kiss , I actually tried the scenarios in your examples prior to posting this question. So I mapped the id with id and eventTime with eventTime.

Input 1:

{ "topic": "test", "subject": "test", "id": null, "eventType": "test", "eventTime": "", "data": { "test": "test" } }

Output 1:

{ "topic": "test", "subject": "test", "id": null, "eventType": "test", "eventTime": "", "data": { "test": "test" } }

Input 2:

{ "topic": "test", "subject": "test", "eventType": "test", "data": { "test": "test" } }

Output 2:

{ "topic": "test", "subject": "test", "eventType": "test", "data": { "test": "test" } }

I also tried mapping id with Id but the same results. It just publishes the same json I passed in the parameters. I got the publish results from the subscriber webhook so I am quite certain it is the actual json that was published.
Roman Kiss 2,246 Reputation points

2023-02-01T21:45:44.9466667+00:00

What's your input event schema on the custom topic?

It looks like, the input schema is not a custom input schema.

Thanks

Roman
JReyes 5 Reputation points

2023-02-06T13:08:17.62+00:00

Hi @Roman Kiss , I tried the exact examples you did in the attached images by mapping the input schema (with "my" prefixes) to a custom event grid topic. The output is on the right side captured by the subscriber webhook. I selected the custom event grid in the subscriber webhook.

Roman Kiss 2,246

Hi,

Could you post your inputSchemaMapping property object?

Go to your Custom Event Grid Topic on the Azure portal and click on the Export template. On the right pane you will get the full ARM template for this resource, where you should see the inputSchemaMapping property,

The following screen snippet shows an inputSchemaMapping property of my custom event grid topic from the above example:

"inputSchemaMapping": {
   "properties": {
      "id": {
             "sourceField": "myId"
            },
      "topic": {},
      "eventTime": {
             "sourceField": "myEventTime"
             },
       "eventType": {
             "sourceField": "myEventType",
             "defaultValue": "myDefaultEventType"
             },
        "subject": {
             "sourceField": "mySubject",
             "defaultValue": "myDefaultSubject"
             },
        "dataVersion": {
             "sourceField": "myDataVersion",
             "defaultValue": "myDefaultDataVersion"
             }
         },
   "inputSchemaMappingType": "Json"
 }

Note, that the inputSchemaMapping property of your custom event grid topic (Topic Endpoint) should be the same as my.

Thanks

Roman

JReyes 5 Reputation points

2023-02-06T17:02:04.5166667+00:00

They're the same except the default values. BTW, I overlooked the duplicate properties in your output example because of using EventGridSchema. Like in your 2nd example, the "id" in the first level is set but you still have "myId" property under "data".

The subscriber webhook in my example is also a custom event schema because I only need to use the default in "id" and "eventTime" from the event grid topic while the same time avoiding duplicate properties under the "data".

Currently I just set it programmatically like in the following example.

https://msftplayground.com/2017/08/azure-event-grid-custom-events/
Roman Kiss 2,246 Reputation points

2023-02-07T08:48:11.33+00:00

Hi @JReyes,

Basically, the AEG makes a transformation from custom input schema to the EventGrid schema and CloudEvent schema such as a wrapping the input event to the well-know schema with a capability for mapping some properties.

Beside that two transformations, the AEG supports also by-passing a custom input schema to the custom output (delivery) schema. Note, that this is not a transformation, the input event message is delivered in the "as it is" manner. That's your case and I hope the AEG team will update documentation about the custom input schema for more clear.

Thanks

Roman

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How to use id and eventTime default values in custom event grid topic?

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