How to get debug information when developing tick script for kapacitor?

Question

I am wondering if during tickscript development, there is any opportunity to dump the stream state after passing through the processing node (log to the file, stdout)?

Answer 1

I am able to dump data from within a tick script into a separate database...

stream
    |from()
        .database('telegraf')
        .measurement('cpu')
        .groupBy(*)
        .where(lambda: "cpu" == 'cpu-total')
    |eval( lambda: 100.0 - "usage_idle" )
        .as('usage_util')
        .keep()
        .quiet()
    |InfluxDBOut()
        .create()
        .database('debugging')

Then I use Chronograf explorer to view the results...

Answer 2

I found it useful putting |httpOut('id') for debugging purposes. Later you can access http://kapacitor-host:9092/kapacitor/v1/tasks/<task_id>/<httpOut_id> and see what data is passing through that node.

Answer 3

Kapacitor has a Log Node that allows you to dump the stream state to the Kapacitor log files.

In use, it would look something like the following:

stream.from()...
  |window()
      .period(10s)
      .every(10s)
  |log()
  |count('value')