processor_opentelemetry_envelope: add new processor docs

Signed-off-by: Eduardo Silva <[email protected]>

Author: edsiper

SUMMARY.md

@@ -130,9 +130,10 @@
   * [Logfmt](pipeline/parsers/logfmt.md)
   * [Decoders](pipeline/parsers/decoders.md)
 * [Processors](pipeline/processors/README.md)
-  * [Labels](pipeline/processors/labels.md)
   * [Content Modifier](pipeline/processors/content-modifier.md)
+  * [Labels](pipeline/processors/labels.md)
   * [Metrics Selector](pipeline/processors/metrics-selector.md)
+  * [OpenTelemetry Envelope](pipeline/processors/opentelemetry-envelope.md)
   * [SQL](pipeline/processors/sql.md)
 * [Filters](pipeline/filters/README.md)
   * [AWS Metadata](pipeline/filters/aws-metadata.md)

pipeline/processors/opentelemetry-envelope.md

@@ -0,0 +1,165 @@
+# OpenTelemetry Envelope
+
+The _OpenTelemetry Envelope` processor is used to transform your data to be compatible with the OpenTelemetry Log schema. If your data was __not__ generated by [OpenTelemetry input](../inputs/opentelemetry.md) and your backend or destination for your logs expects to be in an OpenTelemetry schema.
+
+![](/imgs/processor_opentelemetry_envelope.png)
+
+## Configuration Parameters
+
+The processor does not provide any extra configuration parameter, it can be used directly in your _processors_ Yaml directive.
+
+## Usage Example
+
+In this example, we will use the Dummy input plugin to generate a sample message per second, right after is created the processor `opentelemetry_envelope` is used to transform the data to be compatible with the OpenTelemetry Log schema. The output is sent to the standard output and also to an OpenTelemetry collector which is receiving data in port 4318.
+
+
+__fluent-bit.yaml__
+
+```yaml
+service:
+  flush: 1
+  log_level: info
+
+pipeline:
+  inputs:
+    - name: dummy
+      dummy: '{"message": "Hello World"}'
+
+      processors:
+        logs:
+          - name: opentelemetry_envelope
+
+  outputs:
+    - name : stdout
+      match: '*'
+
+    - name: opentelemetry
+      match: '*'
+      host: 127.0.0.1
+      port: 4318
+```
+
+__otel-collector.yaml__
+
+```yaml
+receivers:
+  otlp:
+    protocols:
+      http:
+        endpoint: 127.0.0.1:4318
+
+exporters:
+  file:
+    path: out.json
+  logging:
+    loglevel: info
+
+service:
+  telemetry:
+    logs:
+      level: debug
+  pipelines:
+    logs:
+      receivers: [otlp]
+      exporters: [file, logging]
+```
+
+ You will notice in the standard output of FLuent Bit will print the raw representation of the schema, however, the OpenTelemetry collector will receive the data in the OpenTelemetry Log schema.
+
+Inspecting the output file `out.json` you will see the data in the OpenTelemetry Log schema:
+
+
+```json
+{
+  "resourceLogs": [
+    {
+      "resource": {},
+      "scopeLogs": [
+        {
+          "scope": {},
+          "logRecords": [
+            {
+              "timeUnixNano": "1722904188085758000",
+              "body": {
+                "stringValue": "dummy"
+              },
+              "traceId": "",
+              "spanId": ""
+            }
+          ]
+        }
+      ]
+    }
+  ]
+}
+```
+
+While OpenTelemetry Envelope enrich your logs with the Schema, you might be interested into take a step further and use the [Content Modifier](../processors/content-modifier.md) processor to modify the content of your logs. Here is a quick example that will allow you to add some resource and scope attributes to your logs:
+
+```yaml
+service:
+  flush: 1
+  log_level: info
+
+pipeline:
+  inputs:
+    - name: dummy
+      dummy: '{"message": "Hello World"}'
+
+      processors:
+        logs:
+          - name: opentelemetry_envelope
+
+          - name: content_modifier
+            context: otel_resource_attributes
+            action: upsert
+            key: service.name
+            value: my-service
+
+  outputs:
+    - name : stdout
+      match: '*'
+
+    - name: opentelemetry
+      match: '*'
+      host: 127.0.0.1
+      port: 4318
+```
+
+The collector JSON output will look like this:
+
+```json
+{
+  "resourceLogs": [
+    {
+      "resource": {
+        "attributes": [
+          {
+            "key": "service.name",
+            "value": {
+              "stringValue": "my-service"
+            }
+          }
+        ]
+      },
+      "scopeLogs": [
+        {
+          "scope": {},
+          "logRecords": [
+            {
+              "timeUnixNano": "1722904465173450000",
+              "body": {
+                "stringValue": "Hello World"
+              },
+              "traceId": "",
+              "spanId": ""
+            }
+          ]
+        }
+      ]
+    }
+  ]
+}
+```
+
+For more details about further processing, read the [Content Modifier](../processors/content-modifier.md) processor documentation.