Event bridge rule to filter event for not empty array

Question

I have an EventBridge event in a pattern similar to below.

{
  "version": "0",
  "id": "816c9de5-517b-a18a-1190-e3e3c2f51f92",
  "detail-type": "ProductTableEvent",
  "source": "pi-data",
  "account": "751354400372",
  "time": "2022-07-07T05:58:26Z",
  "region": "eu-west-1",
  "resources": [],
  "detail": {
    "data": {
      "new": {
        "Gtin": "01234567",
        "NoIngredientsNeeded": 1,
        "DeliveryCostIncluded": 0,
        "MaximumOrder": 0,
        "ProductSegment": "Vardag",
        "StoreProducts": [],
      }
    }
  }
}

And I want to write an event pattern that get triggers when the storeProducts List is not empty.

As not empty is not same as checking for null, I cant use anything-but rule that checks for null. So none of the below rules works here.

  InsertProductRule:
    Type: 'AWS::Events::Rule'
    Properties:
      EventBusName: commerce
      EventPattern:
        source:
          - "my-source"
        detail
          data: 
            new:  
              StoreProducts:
                - exists: true
                - anything-but: []

Any idea how to do it?

Thank you very much!

Paolo · Accepted Answer · 2022-07-08 11:57:54Z

4

You can use the following pattern:

{
  "source": ["pi-data"],
  "detail": {
    "data": {
      "new": {
        "StoreProducts": [{ "exists": true }]
      }
    }
  }
}

this will be triggered when StoreProducts is not an empty list.

When StoreProducts is an empty list:

When StoreProducts is not an empty list:

edited Jul 8, 2022 at 11:57

answered Jul 7, 2022 at 18:20

Paolo

26.6k8 gold badges51 silver badges88 bronze badges

Sign up to request clarification or add additional context in comments.

4 Comments

Chathuri Gunawardhana Over a year ago

No. exists true only check whether StoreProducts property exists. In my case it exists. It is just an empty list.

Paolo Over a year ago

@ChathuriGunawardhana you are mistaken. Test the pattern I gave you in the EventBridge pattern editor

Chathuri Gunawardhana Over a year ago

yes you are right. Trigger skips the empty list with exists filter. I was so caught on phrase "Exists matching works on the presence or absence of a field in the JSON of the event" and was trying to get it work with both exists and anything-but but never tried just with exists. Thank you very much!

Alex Alexiuc Over a year ago

I tried this rule for an array of objects and it doesn't work. Is there a different patter for array of primitives or objects?

Collectives™ on Stack Overflow

Event bridge rule to filter event for not empty array

1 Answer 1

4 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

4 Comments

Your Answer

Sign up or log in

Post as a guest

Related