Prometheus label values API: add rest action#144958
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Implements the REST handler for GET /_prometheus/api/v1/label/{name}/values,
wiring together the plan builder and response listener. Registers the action
in PrometheusPlugin and adds integration tests.
felixbarny
added
>non-issue
v9.4.0
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elasticsearchmachine
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Pinging @elastic/es-storage-engine (Team:StorageEngine) |
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| // Optional limit; default to DEFAULT_LIMIT to avoid unbounded ESQL scans | ||
| int limit = request.paramAsInt(LIMIT_PARAM, DEFAULT_LIMIT); |
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Do we need the default limit? TS transpilation should lead to the respective limits being applied?
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TimeSeriesAggregate does not fit here: it requires _tsid/tbucket groupings and TimeSeriesAggregateFunction aggregates, while we are doing a plain deduplication (GROUP BY label). With a regular Aggregate, AddImplicitLimit's isTsAggregate check is false, so without the explicit default ESQL would cap at 1,000 rows and emit a "No limit defined" header warning. The DEFAULT_LIMIT = 10_000 is needed.
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How can users adjust it? For the other limits, we use cluster settings.
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There’s a limit query parameter for the api
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So it's possible to request 10b results? We should probably add an upper bound and control it through a cluster setting. That can happen in a follow-up.
This reverts commit 3eabbfa.
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This broke compilation of |
Implements the REST handler for GET /_prometheus/api/v1/label/{name}/values,
wiring together the plan builder and response listener. Registers the action
in PrometheusPlugin and adds integration tests.
This reverts commit 3eabbfa.
4 participants
Adds
PrometheusLabelValuesRestAction, the REST handler forGET /_prometheus/api/v1/label/{name}/values. It wires together the plan builder and response listener from the prerequisite PRs and registers the action with the Prometheus plugin. Integration tests are covered byPrometheusLabelValuesRestIT.This is part of a stack implementing the Prometheus label values API endpoint:
Stacking order