Groovy to Painless; get current date time

[rjernst (Ryan Ernst)]

See this previous thread which explains what to do (passing in now through a param):

Painless get date today

Painless intentionally doesn't have any access to now style variables so they can be better cached. The current recommendation is for you to send now style variables in over scripts params. BTW, you should know that this query isn't able to take advantage of the index at all. It'll have to load the @timestamp field for every document and compare it. This much much slower than extracting the day of the week on ingest and adding it to the document.