Disconnect between input and query schema when transforms

[awestendorf]

Transforms are very powerful and allow for turning unique stat names into histograms. For example:

'auth_counts' : {
  'type': 'histogram',
  'match' : '^stats_counts\.auth\.[a-zA-Z0-9]+$',
  'transform' : lambda k,v: ('.'.join(k.split('.')[:-1]), k.split('.')[-1]) if int(v) else (None,None),
  ...
}

Turns stats of the form:
stats_counts.auth.abcd0987 1 1234567890

Into a histogram of {"abcd0987":+1} under the key stats_counts.auth. The problem is that you'd query that stat as stats_counts.auth which does not match the regular expression. One could add a second regex to match on that, but that would be capture incorrect data on the input side.