docs for logs deletion feature (#3826)

* docs for logs deletion feature

* update doc

Co-authored-by: Karen Miller <84039272+KMiller-Grafana@users.noreply.github.com>

Co-authored-by: Karen Miller <84039272+KMiller-Grafana@users.noreply.github.com>

docs/sources/configuration/_index.md

@@ -1613,6 +1613,9 @@ compacts index shards to more performant forms.
 
 # The total amount of worker to use to delete chunks.
 [retention_delete_worker_count: <int> | default = 150]
+
+# Allow cancellation of delete request until duration after they are created. Data would be deleted only after delete requests have been older than this duration. Ideally this should be set to at least 24h.
+[delete_request_cancel_period: <duration> | default = 24h]
 ```
 
 ## limits_config

docs/sources/operations/storage/_index.md

@@ -23,6 +23,7 @@ For more information:
 
 1. [Table Manager](table-manager/)
 1. [Retention](retention/)
+1. [Logs Deletion](logs-deletion/)
 
 ## Supported Stores
 

docs/sources/operations/storage/logs-deletion.md

@@ -0,0 +1,91 @@
+---
+title: Log Entry Deletion
+weight: 60
+---
+# Log Entry Deletion
+
+_This feature is experimental. It is only supported for the BoltDB Shipper index store._
+
+Loki supports the deletion of log entries from specified streams.
+Log entries that fall within a specified time window are those that will be deleted.
+
+The Compactor component exposes REST endpoints that process delete requests.
+Hitting the endpoint specifies the streams and the time window.
+The deletion of the log entries takes place after a configurable cancellation time period expires.
+
+Log entry deletion relies on configuration of the custom logs retention workflow as defined in [Compactor](../retention#compactor). The Compactor looks at unprocessed requests which are past their cancellation period to decide whether a chunk is to be deleted or not.
+
+## Configuration
+
+Enable log entry deletion by setting `retention_enabled` to true in the Compactor's configuration. See the example in [Retention Configuration](../retention#retention-configuration).
+
+A delete request may be canceled within a configurable cancellation period. Set the `delete_request_cancel_period` in the Compactor's YAML configuration or on the command line when invoking Loki. Its default value is 24h.
+
+## Compactor endpoints
+
+The Compactor exposes endpoints to allow for the deletion of log entries from specified streams.
+
+### Request log entry deletion
+
+```
+POST /loki/api/admin/delete
+PUT /loki/api/admin/delete
+```
+
+Query parameters:
+
+* `match[]=<series_selector>`: Repeated label matcher argument that identifies the streams from which to delete. At least one `match[]` argument must be provided.
+* `start=<rfc3339 | unix_timestamp>`: A timestamp that identifies the start of the time window within which entries will be deleted. If not specified, defaults to 0, the Unix Epoch time.
+* `end=<rfc3339 | unix_timestamp>`: A timestamp that identifies the end of the time window within which entries will be deleted. If not specified, defaults to the current time.
+
+A 204 response indicates success.
+
+Sample form of a cURL command:
+```
+curl -X POST \
+  '<compactor_addr>/loki/api/admin/delete?match[]={foo="bar"}&start=1591616227&end=1591619692' \
+  -H 'x-scope-orgid: <tenant-id>'
+```
+
+### List delete requests
+
+List the existing delete requests using the following API:
+
+```
+GET /loki/api/admin/delete
+```
+
+Sample form of a cURL command:
+
+```
+curl -X GET \
+  <compactor_addr>/loki/api/admin/delete \
+  -H 'x-scope-orgid: <orgid>'
+```
+
+This endpoint returns both processed and unprocessed requests. It does not list canceled requests, as those requests will have been removed from storage.
+
+### Request cancellation of a delete request
+
+Loki allows cancellation of delete requests until the requests are picked up for processing. It is controlled by the `delete_request_cancel_period` YAML configuration or the equivalent command line option when invoking Loki.
+
+Cancel a delete request using this Compactor endpoint:
+
+```
+POST /loki/api/admin/cancel_delete_request
+PUT /loki/api/admin/cancel_delete_request
+```
+
+Query parameters:
+
+* `request_id=<request_id>`: Identifies the delete request to cancel; IDs are found using the `delete` endpoint.
+
+A 204 response indicates success.
+
+Sample form of a cURL command:
+
+```
+curl -X POST \
+  '<compactor_addr>/loki/api/admin/cancel_delete_request?request_id=<request_id>' \
+  -H 'x-scope-orgid: <tenant-id>'
+```