[julianocosta89]

Description

Adds the missing piece of the exemplars MVP from perses/perses#3445: an optional enableExemplars toggle on the PrometheusTimeSeriesQuery spec, rendered as an Auto / On / Off button group in the query editor (same pattern as the existing instant toggle).

Semantics:

• Auto (field unset): follow the exemplars.enable setting of the selected datasource — the behavior introduced with the MVP.
• On: fetch exemplars for this query, even when the rest of the panel would not show them otherwise (still gated by the datasource toggle).
• Off: skip the exemplars request for this query, even when the datasource has exemplars enabled.

A per-query On cannot override a datasource-level off: the effective flag is datasource.exemplars.enable === true && (spec.enableExemplars ?? true) && !isInstant — exemplars stay a datasource opt-in feature, and they are only fetched for range queries (the exemplars API is range-based).

Editor UX:

• The button group sits next to the Range/Instant/Auto query-type group.
• It is disabled when exemplars are disabled on the selected datasource (helper text: "Exemplars (disabled on the datasource)") or when the query is instant ("not available for instant queries"), with the state-aware message color so a misconfiguration is visible at a glance.

Also included:

• enableExemplars?: bool in the plugin CUE schema.
• EnableExemplars(bool) option on the Go SDK query builder (mirroring Instant).

Screenshots

Query editor with the Exemplars Auto/On/Off toggle:

Full panel editor context:

Testing

• Unit tests for getTimeSeriesData: enableExemplars: false suppresses the exemplar request even when the datasource enables them; enableExemplars: true does not bypass a datasource-level off; instant queries never fetch exemplars (pre-existing behavior, kept intact).
• tsc --noEmit, oxlint and oxfmt are clean.

[AntoineThebaud]

Thanks @julianocosta89 for following-up on this 🙏 could you just shrink the legend control to make room for these new controls, to avoid using more vertical space for this query form, something like this mockup:

[Gladorme]

Strange to have the same style of inputs. But not the same display (exemplar having a label but not query type) 😕

[AntoineThebaud]

Strange to have the same style of inputs. But not the same display (exemplar having a label but not query type) 😕

Well query type controls are quite self explanatory I think, at a glance you understand what "range" and "instant" are related to, so the label isn't mandatory for user comprehension, and adding a "Query type" label in front would consume too much space in the current state imho. But if we want to have similar look & feel across the 2 controls maybe we could go with dropdown+label for each? Like we have for the Query Type dropdown that comes first in the form (oh y btw "Query type" is already taken then 😅 )

[julianocosta89]

@AntoineThebaud here are the new screenshots:

[Copilot]

🟡 Changes recommended

The exemplars controls remain enabled with misleading helper text for Auto queries on instant-mode panels, and the On/Off/Auto group lacks an accessible name and exposed selected state.

2 open issues

• Resolve effective query mode for exemplar controls · New
• Add accessible labels and selected states to mode controls · New

What changed in this PR

Adds per-query exemplar control to Prometheus time-series queries while preserving datasource opt-in and range-query restrictions.

Changes:

• Adds an Auto/On/Off editor control with datasource and instant-query availability messaging.
• Applies the per-query flag when fetching exemplars and tests opt-out and datasource gating.
• Exposes the optional setting in the TypeScript model, CUE schema, and Go SDK.

File	Description
prometheus/​src/​plugins/​prometheus-time-series-query/​time-series-query-model.ts	Defines the optional enableExemplars field.
prometheus/​src/​plugins/​prometheus-time-series-query/​query-editor-model.ts	Adds immediate-update state handling for the toggle.
prometheus/​src/​plugins/​prometheus-time-series-query/​PrometheusTimeSeriesQueryEditor.tsx	Adds exemplar controls and availability messages.
prometheus/​src/​plugins/​prometheus-time-series-query/​plugin.test.ts	Tests per-query opt-out and datasource gating.
prometheus/​src/​plugins/​prometheus-time-series-query/​get-time-series-data.ts	Includes the query setting in exemplar request gating.
prometheus/​sdk/​go/​query/​query.go	Adds the optional serialized Go field.
prometheus/​sdk/​go/​query/​options.go	Adds the EnableExemplars builder option.
prometheus/​schemas/​prometheus-time-series-query/​query.cue	Allows the optional boolean in query configuration.

_{Review effort: Balanced}

[Copilot]

🔵 Needs a closer look

The exemplar documentation still incorrectly promises a datasource override and fetching for every range query, and must clarify per-query Auto/On/Off behavior and datasource and range-query requirements.

No open issues 🎉

2 previously missed issues

In code that hasn't changed since last review

Correct EnableExemplars datasource override documentation

prometheus/​sdk/​go/​query/​options.go:71

EnableExemplars(true) cannot enable fetching when the datasource disables exemplars, so this documentation incorrectly promises an override. Document that datasource opt-in remains required, omission follows the datasource setting, and false skips fetching. The same correction is needed in prometheus/src/plugins/prometheus-time-series-query/time-series-query-model.ts:28–30.

Update exemplar docs for the per-query Auto/On/Off option

prometheus/​src/​plugins/​prometheus-time-series-query/​get-time-series-data.ts:129

This changes the documented behavior: docs/prometheus/README.md:137 still says an enabled datasource fetches exemplars with every range query, which is no longer true when enableExemplars is false. Please update the exemplar guide and query model documentation to describe the per-query Auto/On/Off option and clarify that On still requires an enabled datasource and a range query.

2 resolved since last review

• Add accessible labels and selected states to mode controls
• Resolve effective query mode for exemplar controls

_{Review effort: Balanced}

[julianocosta89]

@Gladorme and @AntoineThebaud anything missing here?

The latest screenshots are here: #877 (comment)

[AntoineThebaud]

@Gladorme and @AntoineThebaud anything missing here?

The latest screenshots are here: #877 (comment)

Sorry for the delay on this topic @julianocosta89, I will have time tomorrow to review this one & #876 as well

[julianocosta89]

@AntoineThebaud Any chance you are attending KubeCon?!

[AntoineThebaud]

@julianocosta89 not the current NA edition but I should be there at the next EU one in 2027

[AntoineThebaud]

LGTM