Adding ability to live poll from loki to generate metrics

[kushagar]

so we have a use case where we are running nginx inside kubernetes and we want to generate metrics from logs but we don't to run exporter in as a side car for each nginx. we already have promtail running on every node so we are planning to live poll logs from their and generate metrics from it. so my question is , would this be a useful functionality to add to this exporter here in opensource too?