The scrape manage receiver's channel now just saves the target sets
and another backgorund runner updates the scrape loops every 5 seconds.
This is so that the scrape manager doesn't block the receiving channel
when it does the long background reloading of the scrape loops.
Active and dropped targets are now saved in each scrape pool instead of
the scrape manager. This is mainly to avoid races when getting the
targets via the web api.
When reloading the scrape loops now happens in parallel to speed up the
final disared state and this also speeds up the prometheus's shutting
down.
Also updated some funcs signatures in the web package for consistency.
Signed-off-by: Krasi Georgiev <kgeorgie@redhat.com>
This adds a per-target cache of scraped metadata. The metadata is only
available for the lifecycle of the attached target. An API endpoint allows
to select metadata by metric name and a label selection of targets.
Signed-off-by: Fabian Reinartz <freinartz@google.com>
Fix race by properly locking access to scrape pools. Use separate mutex for information needed by UI so that UI isn't blocked when targets are being updated.
