Configure Loki deletion plan when using TSDB or BoltDB shipper as index store

Big Bang currently has no deletion plan in Loki. This was discovered when validating the Loki / Deletion dashboard. Related to issue - set default log retention length.

Log entry deletion
Grafana Loki supports the deletion of log entries from a specified stream. Log entries that fall within a specified time window and match an optional line filter are those that will be deleted.

Log entry deletion is supported only when TSDB or BoltDB shipper is configured as the index store.

May also want to consider adding documentation for instructions with how to curl a POST to trigger deletion of stream (?). Something like curl -g -X POST 'http://localhost:15090/loki/api/v1/delete?query={label="YYY"}&start=1591616227' -H 'X-Scope-OrgID: 1' from shell in Loki Gateway container.

Resources:

• Loki - Storage/Log entry deletion
• Loki - Storage/Log entry deletion#configuration for implementation details