django_up or up metric?

[anarcat]

I think it would be great to have a basic up metric in this exporter. It's pretty standard to have this as a mechanism to be able to tell if the exporter works or not.

Right now, for basic availability, i need to revert to something like python_info (which doesn't work in multiproc) or the existence (but not value!) of a metric like django_http_requests_body_total_bytes_bucket, which might not actually exist until the site is hit...