# OpenTelemetry

The OpenTelemetry plugin allows you to ingest telemetry data as per the OTLP specification, from various OpenTelemetry exporters, the OpenTelemetry Collector, or Fluent Bit's OpenTelemetry output plugin.

## Configuration <a href="#configuration" id="configuration"></a>

| Key                        | Description                                                                                                                                     | default |
| -------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------- | ------- |
| listen                     | The address to listen on                                                                                                                        | 0.0.0.0 |
| port                       | The port for Fluent Bit to listen on                                                                                                            | 4318    |
| tag\_key                   | Specify the key name to overwrite a tag. If set, the tag will be overwritten by a value of the key.                                             |         |
| raw\_traces                | Route trace data as a log message                                                                                                               | false   |
| buffer\_max\_size          | Specify the maximum buffer size in KB to receive a JSON message.                                                                                | 4M      |
| buffer\_chunk\_size        | This sets the chunk size for incoming incoming JSON messages. These chunks are then stored/managed in the space available by buffer\_max\_size. | 512K    |
| successful\_response\_code | It allows to set successful response code. `200`, `201` and `204` are supported.                                                                | 201     |

Important note: Raw traces means that any data forwarded to the traces endpoint (`/v1/traces`) will be packed and forwarded as a log message, and will NOT be processed by Fluent Bit. The traces endpoint by default expects a valid protobuf encoded payload, but you can set the `raw_traces` option in case you want to get trace telemetry data to any of Fluent Bit's supported outputs.

## Getting started

The OpenTelemetry plugin currently supports the following telemetry data types:

| Type    | HTTP/JSON     | HTTP/Protobuf |
| ------- | ------------- | ------------- |
| Logs    | Stable        | Stable        |
| Metrics | Unimplemented | Stable        |
| Traces  | Unimplemented | Stable        |

A sample config file to get started will look something like the following:

```
[INPUT]
	name opentelemetry
	listen 127.0.0.1
	port 4318

[OUTPUT]
	name stdout
	match *
```

With the above configuration, Fluent Bit will listen on port `4318` for data. You can now send telemetry data to the endpoints `/v1/metrics`, `/v1/traces`, and `/v1/logs` for metrics, traces, and logs respectively.

A sample curl request to POST json encoded log data would be:

```
curl --header "Content-Type: application/json" --request POST --data '{"resourceLogs":[{"resource":{},"scopeLogs":[{"scope":{},"logRecords":[{"timeUnixNano":"1660296023390371588","body":{"stringValue":"{\"message\":\"dummy\"}"},"traceId":"","spanId":""}]}]}]}'   http://0.0.0.0:4318/v1/logs
```