Elapsed time between consecutive logs

Elastic Stack Logstash
1

I know a quite similar question was raised in Time between timestamp but a clear answer wasn't given there.

I would like to calculate the difference between every consecutive logs timestamp and insert the result as a new field in the latter log.
I guess the elapsed filter is my best bet, but I am rather new to logstash and I couldn't find out how I should do it.
Any help would be appreciated.

2

i don't think you could do that with the elapsed filter because for him an event can only be a start event for the timer OR an end event.

I think your only possibility will be the ruby filter.

3

Any idea on how can I get the timestamp of the previous log with ruby? With that the problem should be solved.

4

You can saved it in a variable of the ruby plugin (needs worker set to 1 like the elapsed plugin to give always the correct value)
it should be something like this:

ruby {
    ruby {
        init => "$last_time = 0.0;"
        code => "event.set('elapsed_time', event.get('@timestamp').to_f-$last_time); $last_time = event.get('@timestamp').to_f;"
    }
}

untested because i didn't have a test system handy where i can test this

EDIT: ok i have tested it now there where some errors in there that i have now fixed and it has now a higher precision (not only down to 1s)

5

Thank you for the help. It seems to work fine.

6

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