fluent-plugin-opentelemetry

Fluentd input/output plugin to forward OpenTelemetry Protocol data.

Installation

RubyGems

gem install fluent-plugin-opentelemetry

Bundler

gem "fluent-plugin-opentelemetry"

And then execute:

$ bundle

Configuration

Input opentelemetry plugin

To receive data, this plugin requires <http> or <grpc> section, or both.

Root section

parameter	type	description	default
tag	string	The tag of the event	required

tag parameter supports ${type} placeholder and it will be expanded with data type.

• log data
  • ${type} will be replaced to logs
• metric data
  • ${type} will be replaced to metrics
• trace data
  • ${type} will be replaced to traces

This can be used to change the output destination for each message type.

Example:

<source>
  @type opentelemetry

  # Expand to opentelemetry.logs, opentelemetry.metrics, opentelemetry.traces according to received data.
  tag opentelemetry.${type}

  <http>
    bind 127.0.0.1
    port 4318
  </http>
</source>

<http> section

This requires to receive data via HTTP/HTTPS.

parameter	type	description	default
bind	string	The address to bind to	0.0.0.0
port	integer	The port to listen to	4318

<grpc> section

This requires to receive data via gRPC. It needs to install grpc gem manually to use this feature.

Warning

Now, gRPC feature status is experimental.

parameter	type	description	default
bind	string	The address to bind to	0.0.0.0
port	integer	The port to listen to	4317

• <transport> section

Refer Config: Transport Section

Example

<source>
  @type opentelemetry
  tag opentelemetry

  <http>
    bind 0.0.0.0
    port 4318
  </http>

  <grpc>
    bind 0.0.0.0
    port 4317
  </grpc>
</source>

Input opentelemetry_metrics plugin

This plugin emits Fluentd's metric data that conforms to the OpenTelemetry Protocol. To output the data, it requires to use output opentelemetry plugin.

Root section

parameter	type	description	default
tag	string	The tag of the event	required
emit_interval	time	Determine the rate to emit internal metrics as events	60
metric_name_prefix	string	The prefix of metric name	fluentd_

Example

# Emit Fluentd metrics
<source>
  @type opentelemetry_metrics
  tag opentelemetry.fluentd.metrics
  emit_interval 300s
</source>

# Send Fluentd metrics to OpenTelemetry Collector
<match opentelemetry.fluentd.metrics>
  @type opentelemetry

  <http>
    endpoint "https://127.0.0.1:4318"
  </http>
</match>

Output opentelemetry plugin

To send data, this plugin requires <http> or <grpc> section.

<http> section

This requires to send data via HTTP/HTTPS.

parameter	type	description	default
endpoint	string	The endpoint for HTTP/HTTPS request	http://127.0.0.1:4318
proxy	string	The proxy for HTTP/HTTPS request	nil
error_response_as_unrecoverable	bool	Raise UnrecoverableError when the response code is not SUCCESS	true
retryable_response_codes	array	The list of retryable response codes	[429, 502, 503, 504]
read_timeout	integer	The read timeout in seconds	60
write_timeout	integer	The write timeout in seconds	60
connect_timeout	integer	The connect timeout in seconds	60

parameter	type	description	available values	default
compress	enum	The option to compress HTTP request body	text / gzip	text

<grpc> section

This requires to send data via gRPC. It needs to install grpc gem manually to use this feature.

Warning

Now, gRPC feature status is experimental.

parameter	type	description	default
endpoint	string	The endpoint for HTTP/HTTPS request	127.0.0.1:4317

<transport> section

parameter	type	description	default
cert_path	string	Specifies the path of Certificate file	nil
private_key_path	string	Specifies the path of Private Key file	nil
private_key_passphrase	string	Specifies the public CA private key passphrase	nil

parameter	type	description	available values	default
min_version	enum	Specifies the lower bound of the supported SSL/TLS protocol	TLS1_1 / TLS1_2 / TLS1_3	nil
max_version	enum	The endpoint for HTTP/HTTPS request	TLS1_1 / TLS1_2 / TLS1_3	nil

Refer Config: Transport Section

<buffer> section

parameter	type	description	default
chunk_keys	array	Overwrites the default chunk_keys value in this plugin.	tag

Refer Config: Buffer Section

Example

<match opentelemetry.**>
  @type opentelemetry

  <http>
    endpoint "https://127.0.0.1:4318"
  </http>
</match>

Copyright

• Copyright(c) 2025- Shizuo Fujita
• License
  • Apache License, Version 2.0