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>
Extends the parser to allow retrieving metadata.
The lexer now yields proper tokens that are fed into a hand-written
parser on top.
Signed-off-by: Fabian Reinartz <freinartz@google.com>
This commit avoids passing the full scrape configuration down to the
scrape loop to fix data races when the scrape configuration is being
reloaded.
Signed-off-by: Simon Pasquier <spasquie@redhat.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.
The semantics of honor_labels are that if a target exposes
and empty label it will override the target labels. This PR
fixes that by once again distinguishing between empty labels
and missing labels in this one use case.
Beyond that empty labels should be pruned and not added to storage,
which this also fixes.
Fixes#3841
