"last metrics" are not reported to Datadog - Artillery exits

[anroots]

The last metrics of an Artillery test (past ~15 secs?) are not reported to Datadog - Artillery main process exits before this is done. It is especially obvious with a short test, for example:

# test.yaml
config:
  target: https://sqroot.eu
  phases:
    - duration: 3
      arrivalRate: 2
      name: "First stage"
  plugins:
    datadog:
      # Custom hostname (leave blank if not desired)
      host: 'test-host'
      # Custom metric prefix (defaults to 'artillery.')
      prefix: 'artillery.'
      # Additional tags for all metrics
      tags:
        - 'mode:test'
scenarios:
  - flow:
      - get:
          url: /

Running it...

$ DEBUG=metrics,plugin:datadog DATADOG_API_KEY=secret ./node_modules/.bin/artillery run test.yaml

... results in no metrics in Datadog.

Increasing the test duration to 20 seconds results in metrics reported. Probably a bug in the way the done event is handled or data is flushed.

Both versions 0.1 and 0.2 are affected -- needs investigation.

[anroots]

Note to self: consider making flush interval configurable.