docs: Clarify config for console decision logger

Clarify the requirements/caveats for using the local decision logger
and include a blurb on the decision log.

Signed-off-by: Patrick East <east.patrick@gmail.com>

docs/content/configuration.md

@@ -312,7 +312,7 @@ services:
 | `decision_logs.reporting.max_delay_seconds` | `int64` | No (default: `600`) | Maximum amount of time to wait between uploads. |
 | `decision_logs.mask_decision` | `string` | No (default: `system/log/mask`) | Set path of masking decision. |
 | `decision_logs.plugin` | `string` | No | Use the named plugin for decision logging. If this field exists, the other configuration fields are not required. |
-| `decision_logs.console` | `boolean` | No (default: `false`) | Log the decisions locally at `info` level to the console. If enabled a `service` or `plugin` _must_ be specified | 
+| `decision_logs.console` | `boolean` | No (default: `false`) | Log the decisions locally at `info` level to the console. When enabled alongside a remote decision logging API the `service` must be configured, the default `service` selection will be disabled. | 
 
 ## Discovery
 

docs/content/decision-logs.md

@@ -69,6 +69,21 @@ Decision log updates contain the following fields:
 | `[_].metrics` | `object` | Key-value pairs of [performance metrics](../rest-api#performance-metrics). |
 | `[_].erased` | `array[string]` | Set of JSON Pointers specifying fields in the event that were erased. |
 
+
+## Local Decision Logs
+
+Local console logging of decisions can be enabled via the `console` config option.
+This does not require any remote server. Example of minimal config to enable:
+
+```yaml
+decision_logs:
+    console: true
+```
+
+This will dump all decision through the OPA logging system at the `info` level. See
+[Configuration Reference](../configuration) for more details.
+
+
 ## Masking Sensitive Data
 
 Policy queries may contain sensitive information in the `input` document that