Return annotations (warnings and infos) from PromQL queries
This generalizes the warnings we have already used before (but only for problems with remote read) as "annotations".
Annotations can be warnings or infos (the latter could be false positives). We do not treat them different in the API for now and return them all as "warnings". It would be easy to distinguish them and return infos separately, should that appear useful in the future.
The new annotations are then used to create a lot of warnings or infos during PromQL evaluations. Partially these are things we have wanted for a long time (e.g. inform the user that they have applied `rate` to a metric that doesn't look like a counter), but the new native histograms have created even more needs for those annotations (e.g. if a query tries to aggregate float numbers with histograms).
The annotations added here are not yet complete. A prominent example would be a warning about a range too short for a rate calculation. But such a warnings is more tricky to create with good fidelity and we will tackle it later.
Another TODO is to take annotations into account when evaluating recording rules.
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Signed-off-by: Jeanette Tan <jeanette.tan@grafana.com>
* remote/read_handler: pool input to Marshal()
Use a sync.Pool to reuse byte slices between calls to Marshal() in the
remote read handler.
Signed-off-by: Giedrius Statkevičius <giedrius.statkevicius@vinted.com>
* remote: add microbenchmark for remote read handler
Signed-off-by: Giedrius Statkevičius <giedrius.statkevicius@vinted.com>
Signed-off-by: Giedrius Statkevičius <giedrius.statkevicius@vinted.com>
This creates a new `model` directory and moves all data-model related
packages over there:
exemplar labels relabel rulefmt textparse timestamp value
All the others are more or less utilities and have been moved to `util`:
gate logging modetimevfs pool runtime
Signed-off-by: beorn7 <beorn@grafana.com>
* Move remote read handler to remote package.
This follows the pattern I started with the remote write handler. The api/v1 package is getting pretty cluttered. Moving code to other packages helps reduce this size and also makes it reusable - eg Cortex doesn't do streaming remote writes yet, and will very soon.
Signed-off-by: Tom Wilkie <tom.wilkie@gmail.com>
* Deal with a nil remoteReadHandler for tests.
Signed-off-by: Tom Wilkie <tom.wilkie@gmail.com>
* Remove the global metrics.
Signed-off-by: Tom Wilkie <tom.wilkie@gmail.com>
* Fix test.
Signed-off-by: Tom Wilkie <tom.wilkie@gmail.com>
* Review feedback.
Signed-off-by: Tom Wilkie <tom.wilkie@gmail.com>
