How do I format numbers within Bosun templates?

Question

In a Bosun template, is it possible to format the output of an evaluated variable from the alert to less decimal places of precision?

Simple Example:

template test_template{
    subject = test
    body = {{.Eval .Alert.Vars.average_runtime}} seconds
}
alert test_alert{
    template test_template
    $average_runtime = avg(q("avg:metric_name", "24h",""))
    crit = $average_runtime > 150.0
}

Results in

190.71165892385326 seconds

in the template body, which is unnecessarily precise. Ideally I would like to see:

190.71 seconds

Answer 1

In go templates you can use printf to format output according to whatever format string you want. This snippet works for me:

template test_template{
  subject = test
  body = {{printf "%.3f" (.Eval .Alert.Vars.average_runtime)}} seconds
}

alert test_alert{
  template = test_template
  $average_runtime = 1234.5678999
  crit = 1
}