Filtering by header content

[ErykCh]

Hi, I would like to be able to filter using data in header. For example.

Message has in the header key: metadata and value for this key: {"source":"SUMPTIONBUCKETS"}

I would like to put in the filter return header.metadata.source == 'SUMPTIONBUCKETS' to get this message.

[rikimaru0345]

That should already be possible.

Try this as filter code: return headers["metadata"].source == "SUMPTIONBUCKETS";

[ErykCh]

Thanks.

It's nice if it was added to the tooltip visible after hovering over Parameters and Examples.

Because this is difficult to guess without analyzing the source code.

[ErykCh]

And I think doing return header.metadata.source == 'SUMPTIONBUCKETS'; instead return headers["metadata"].source == "SUMPTIONBUCKETS"; it would be consistent with the other parameters and more readable.

[rikimaru0345]

I think both types of access should already work. (If not, it might be a bug in the interpreter)

I'll add headers and a few examples to the help things at the bottom 👍

[ErykCh]

Yes, return headers.metadata.source == 'SUMPTIONBUCKETS' works. I used header instead of headers.

But I'm not able to retrieve data when value is directly under a key in headers. So I have key: isDeleted value: boolean key: schemaVersion value: String key: exportDuration value: integer

and the following do not work return headers.isDeleted == false return !headers.isDeleted return headers["isDeleted"] == false return !headers["isDeleted"]

return headers.schemaVersion == 'v2.3.0'

but the numbers work (I have correct results):

return headers.exportDuration > 200

[rikimaru0345]

Glad to hear that property-access works.

But the other issue (maybe it's because it is a boolean or something??) is definitely a bug. I will put it on my list and find out what's going on when I have some time 👍

[twmb]

@rikimaru0345 was this resolved?

[weeco]

This may be a problem in the backend too. To be investigated.

[armsargis]

Hi in the code: backend/pkg/kafka/consumer.go:287

vm.Set("headers", args.HeadersByKey)

And HeadersByKey is defined as:

HeadersByKey map[string][]byte

So it seems that during evaluation, it is interpreted as an Array in JavaScript. When I try:

String.fromCharCode.apply(null, headers.eventId) == '18216' it works as expected. Also, the condition:

headers.eventId instanceOf Array returns true

[armsargis]

Probably converting map values to strings should be fine:

vm.Set("headers", convertToStringValues(args.HeadersByKey))

func convertToStringValues(data map[string][]byte) map[string]string {
	converted := make(map[string]string, len(data))
	for key, byteValue := range data {
		converted[key] = string(byteValue)
	}

	return converted
}

However, this means the documentation should be updated accordingly and, if type conversion is needed, it should be done in JavaScript itself.