Add loki maximum lines config provisioning

[sergeyshaykhullin]

I need a way to set default maximum lines for provisioned Loki datasource

Here:

Now it is hardcoded if i understand correct

grafana/pkg/tsdb/loki/loki.go

Line 147 in fbd8dc5

//Currently hard coded as not used - applies to log queries

[ivanahuckova]

Hello @sergeyshaykhullin ! As you can see in the documentation, you can customize maxLines.

Now it is hardcoded if i understand correct

This is code that is currently used ONLY for alerting where we support only metrics loki queries, therefore line limit is not used there. The code trough which dashboard and explore queries are run is here:

https://github.com/grafana/grafana/blob/main/public/app/plugins/datasource/loki/datasource.ts#L151

[sergeyshaykhullin]

Thanks!