Document filters as processors

SUMMARY.md

@@ -147,6 +147,7 @@
   * [Metrics Selector](pipeline/processors/metrics-selector.md)
   * [OpenTelemetry Envelope](pipeline/processors/opentelemetry-envelope.md)
   * [SQL](pipeline/processors/sql.md)
+  * [Filters as processors](pipeline/processors/filters.md)
   * [Conditional processing](pipeline/processors/conditional-processing.md)
 * [Filters](pipeline/filters/README.md)
   * [AWS Metadata](pipeline/filters/aws-metadata.md)

pipeline/processors/README.md

@@ -19,6 +19,7 @@ Fluent Bit offers the following processors:
 - [OpenTelemetry Envelope](opentelemetry-envelope.md): Transform logs into an
   OpenTelemetry-compatible format.
 - [SQL](sql.md): Use SQL queries to extract log content.
+- [Filters](filters.md): Any filter can be used as a processor.
 
 ## Features
 

pipeline/processors/filters.md

@@ -0,0 +1,24 @@
+# Filters as processors
+
+Any Fluent Bit [filter](../filters/README.md) can be used as a processor.
+
+## Grep example
+
+In this example, the [Grep](../filters/grep.md) filter is used as an output processor that sends log records only if they match a specified regular expression.
+
+{% code title="fluent-bit.yaml" %}
+```yaml
+pipeline:
+  inputs:
+    - name: tail
+      path: lines.txt
+      parser: json
+  outputs:
+    - name: stdout
+      match: '*'
+      processors:
+        logs:
+          - name: grep
+            regex: log aa
+```
+{% endcode %}