Bloblang interpolation with custom binary plugin

[Arenash13]

Hello,

I have a case where I need to assign messages to a specific Kafka topic in the same style as https://www.benthos.dev/docs/configuration/interpolation#bloblang-queries

output:
  kafka:
    addresses: [ "TODO:6379" ]
    topic: 'dope-${! json("topic") }'

The only difference is that these are binary payloads where I search for specific bytes to determine the route.
I started to write a bloblang plugin but I'm not sure if it works out of the box and if I have to do anything to keep the original payload "untouched".

Is there a specific example I can rely on with similar constraints ?

Thanks in advance

[mihaitodor]

Hey @Arenash13

I started to write a bloblang plugin but I'm not sure if it works out of the box and if I have to do anything to keep the original payload "untouched".

You can simply return the original message similar to the noop processor. See here.

However, depending on the binary format, bloblang should have the required utilities you'd need to do basic binary parsing and comparisons. Have a look at the content() function and then you can use something like the encode() method to get a string representation or slice() to get byte chunks or individual bytes.

[mihaitodor]

PS: Converting to a discussion as per #2026.