Working with key:value arrays

Elastic Stack Logstash
1

Good day !

Accordingly to my logstash configuration I get a message with an array consists of key:value pairs.

I have to mutate it on a very special way adding two fields and put there the key and the value . For example

An incoming message looks like:

"22.114":"1234,88","22.456":"345"

So the mutated one should look as

"Field1":"22.114","Field2":"1234,88"
"Field1":"22.456","Field2":"345"

I guess that I should use ruby but it is unclear to me how to use it to get the result.
Any help would be appreciated.

Thanks

2

It is unclear what you want to do. Do you want two events each containing [Field1] and [Field2]?

3

I have an event looks like an array of key:value pairs . I want to transform it into multiple events ,where each of them consists of two fields . A first field value is the key from array and a second field value is the value from array.
Sure , based on my example I want to transform the array into 2 events with those 2 fields

4

Your values contain commas, so a simple mutate+split will incorrectly parse the [message]. Luckily, a kv filter parses it correctly

kv { field_split => "," value_split => ":" trim_key => '"' target => "[@metadata][kvData]" }
    ruby {
        code => '
            kvData = event.get("[@metadata][kvData]")
            if kvData
                data = []
                kvData.each { |k, v|
                    data << { "Field1" => k, "Field2" => v }
                }
                event.set("someField", data)
            end
        '
    }
    split { field => "someField" }

You can move the results to the top level using this code.

I think using a kv filter is fragile, and I would do it in ruby.

    ruby {
        code => '
            matches = event.get("message").scan(/"([^"]*)":"([^"]*)"(,|$)/)
            data = []
            matches.each_index { |x|
                data << { "Field1" => matches[x][0], "Field2" => matches[x][1] }
            }
            event.set("someField", data)
        '
    }
    split { field => "someField" }

Although that regexp may not be any less fragile than the kv filter :smiley:

1 Like
5

Thanks a lot ! It is the thing I have been looking for !

6

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