Fluentd
1.0
1.0
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  • Plugin Development
    • How to Write Input Plugin
    • How to Write Base Plugin
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    • How to Write Filter Plugin
    • How to Write Formatter Plugin
    • How to Write Output Plugin
    • How to Write Parser Plugin
    • How to Write Storage Plugin
    • How to Write Service Discovery Plugin
    • How to Write Tests for Plugin
    • Configuration Parameter Types
    • Upgrade Plugin from v0.12
  • Plugin Helper API
    • Plugin Helper: Child Process
    • Plugin Helper: Compat Parameters
    • Plugin Helper: Event Emitter
    • Plugin Helper: Event Loop
    • Plugin Helper: Extract
    • Plugin Helper: Formatter
    • Plugin Helper: Inject
    • Plugin Helper: Parser
    • Plugin Helper: Record Accessor
    • Plugin Helper: Server
    • Plugin Helper: Socket
    • Plugin Helper: Storage
    • Plugin Helper: Thread
    • Plugin Helper: Timer
    • Plugin Helper: Http Server
    • Plugin Helper: Service Discovery
  • Troubleshooting Guide
  • Appendix
    • Update from v0.12 to v1
    • td-agent v2 vs v3 vs v4
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On this page
  • Example Configuration
  • Plugin Helpers
  • Parameters
  • @type
  • tag
  • port
  • bind
  • source_hostname_key
  • source_address_key
  • message_length_limit
  • remove_newline
  • receive_buffer_size
  • <transport> Section
  • <parse> Section
  • Code Example
  • FAQ
  • How to prevent request drop?
  • How to receive binary data that contains newline bytes

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  1. Input Plugins

udp

PreviousforwardNexttcp

Last updated 5 months ago

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The in_udp Input plugin enables Fluentd to accept UDP payload.

It is included in Fluentd's core.

Example Configuration

<source>
  @type udp
  tag mytag # required
  <parse>
    @type regexp
    expression /^(?<field1>\d+):(?<field2>\w+)$/
  </parse>
  port 20001               # optional. 5160 by default
  bind 0.0.0.0             # optional. 0.0.0.0 by default
  message_length_limit 1MB # optional. 4096 bytes by default
</source>

Plugin Helpers

Parameters

@type

The value must be udp.

tag

type
default
version

string

required parameter

0.14.0

The tag of the output events.

port

type
default
version

integer

5160

0.14.0

The port to listen to. (default: 5160)

bind

type
default
version

string

0.0.0.0 (all addresses)

0.14.0

The bind address to listen to.

source_hostname_key

type
default
version

string

nil (no adding hostname)

0.14.10

The field name of the client's hostname. If it is set, the client's hostname will be set to its key.

If you set the following configuration:

source_hostname_key client_host

then the client's hostname is set to client_host field i.e.:

{
    ...
    "foo": "bar",
    "client_host": "client.hostname.org"
}

source_address_key

type
default
version

string

nil (no adding source address)

1.4.2

The field name for the client's IP address. If you set this option, Fluentd automatically adds the remote address to each data record.

For example, if you have the following configuration:

<source>
  @type udp
  source_address_key client_addr
  # ...
</source>

You will get something like this:

{
    ...
    "client_addr": "192.168.10.10"
    ...
}

message_length_limit

type
default
version

size

4096

0.14.14

The maximum number of bytes for the message.

remove_newline

type
default
version

bool

true

0.14.23

Removes the newline from the end of the incoming payload.

receive_buffer_size

type
default
version

size

nil

1.0.1

This is a deprecated parameter. Use receive_buffer_size in <transport> section instead.

The max size of socket receive buffer. This is used in SO_RCVBUF socket option.

<transport> Section

type
default
available values
version

enum

udp

udp

1.18.0

<parse> Section

required
multi
version

true

false

0.14.10

in_udp uses the parser plugin to parse the payload.

For more details:

Code Example

Here is a Ruby example to send an event to in_udp:

require 'socket'

us = UDPSocket.open
sa = Socket.pack_sockaddr_in(5160, '127.0.0.1')

# This example uses json payload.
# In in_udp configuration, need to configure "@type json" in "<parse>"
us.send('{"k":"v1"}', 0, sa)
us.send('{"k":"v2"}', 0, sa)
us.close

FAQ

How to prevent request drop?

If in_udp gets lots of packets within 1 sec, some packets are dropped. For example, you can see bigger RcvbufErrors number via netstat -su.

How to receive binary data that contains newline bytes

If you are trying to receive binary data containing '\r' (0x0d) or '\n' (0x0a), you need to tweak remove_newline to prevent Fluentd from corrupting payloads.

For example, suppose you intend to receive packets which contain the following data:

\xa9test\ntest (0xa9, 0x74, 0x65, 0x73, 0x74, 0xa, 0x74, 0x65, 0x73, 0x74)

you need to be careful that the default behaviour of Fluentd is to trim the 6th byte (0x0a) from payload. If you do not want this behaviour, please configure remove_newline to false.

Refer to the article for the basic structure and syntax of the configuration file.

For <parse>, refer to .

We have observed drastic performance improvements on Linux, with proper kernel parameter settings (e.g. net.core.rmem_max parameter). If you have high-volume UDP traffic, please make sure to follow instructions.

See .

This section is for some general transport configurations. See for all supported parameters.

This means that in_udp with one process cannot handle such traffic loads. Try .

If this article is incorrect or outdated, or omits critical information, please . is an open-source project under . All components are available under the Apache 2 License.

Configuration File
Parse Section
Before Installing Fluentd
server
parser
extract
compat_parameters
Common Parameters
Config: Transport Section
Parser Plugin Overview
Parse Section Configurations
multi workers
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