Support exemplars like datapoints on Logql metrics queries in Loki

[ajitpatil]

Loki datasource already supports linking specific fields like traceId to Jaeger datasource. It shows as a link on a popup in raw logs view. But similar feature could be added with exemplar-like datapoints on the time-series panels with log metrics queries in Loki datasource.

[liguozhong]

grafana issue: <Loki: Show log samples for metric queries>
grafana/grafana#52088

[ajitpatil]

@liguozhong Thanks for linking this feature request to that.

[liguozhong]

This feature is great, I very much hope that loki can implement the feature mentioned in this issue. This can make loki more powerful and can realize powerful feature such as LogReduce. Our team needs this LogReduce feature very much. We raised related issues 2 years ago. But it has not been realized for a long time.

What do you want from Loki in 2021? ：
#3119 (comment)

https://help.sumologic.com/docs/search/logreduce/detect-patterns-with-logreduce/

[liguozhong]

@liguozhong Thanks for linking this feature request to that.

Hi, @ajitpatil，Thans for the detailed picture design.
I submit a PR to support the http api. If this PR is successfully merged, you need to file an issue in the github of grafana/grafana to support the display of exemplars data including explore and panel in the grafana UI. This issue will be a long process, looking forward to having this powerful feature.

#7974