The prometheus text format requires metrics endpoints respond with the
content-type 'text/plain; version=0.0.4'. Without this, newer versions
of prometheus fail to scrape the metrics endpoint and report an error.
It's possible to work around this by setting the
'fallback_scrape_protocol' setting in the prometheus scrape target
configuration, but this revision sets the content type appropriately to
avoid this in the first place.
This adds standard OAuth2 client credentials and bearer token support as
well as scope-based authorization checks for REST API clients. Note that
this initial implementation should not be used in production and that
the access token limit has not been implemented yet.
Signed-off-by: Michael Mayer <michael@photoprism.app>
Expose a new API which can be scraped by prometheus to gather useful
metrics from an instance. The new endpoint exposes photoprism build
version information, golang version, edition and various count metrics.
