Tcp input plugin
editTcp input plugin
edit- Plugin version: v6.4.3
- Released on: 2024-10-16
- Changelog
For other versions, see the Versioned plugin docs.
Getting help
editFor questions about the plugin, open a topic in the Discuss forums. For bugs or feature requests, open an issue in Github. For the list of Elastic supported plugins, please consult the Elastic Support Matrix.
Description
editRead events over a TCP socket.
Like stdin and file inputs, each event is assumed to be one line of text.
Can either accept connections from clients or connect to a server,
depending on mode
.
Accepting log4j2 logs
editLog4j2 can send JSON over a socket, and we can use that combined with our tcp input to accept the logs.
First, we need to configure your application to send logs in JSON over a socket. The following log4j2.xml accomplishes this task.
Note, you will want to change the host
and port
settings in this
configuration to match your needs.
<Configuration> <Appenders> <Socket name="Socket" host="localhost" port="12345"> <JsonLayout compact="true" eventEol="true" /> </Socket> </Appenders> <Loggers> <Root level="info"> <AppenderRef ref="Socket"/> </Root> </Loggers> </Configuration>
To accept this in Logstash, you will want tcp input and a date filter:
input { tcp { port => 12345 codec => json } }
and add a date filter to take log4j2’s timeMillis
field and use it as the
event timestamp
filter { date { match => [ "timeMillis", "UNIX_MS" ] } }
Event Metadata and the Elastic Common Schema (ECS)
editIn addition to decoding the events, this input will add metadata about the TCP connection itself to each event. This can be helpful when applications are configured to send events directly to this input’s TCP listener without including information about themselves.
Historically, this metadata was added to a variety of non-standard top-level fields, which had the potential to create confusion and schema conflicts downstream. With ECS compatibility mode, we can ensure a pipeline still has access to this metadata throughout the event’s lifecycle without polluting the top-level namespace.
Metadata Group | ecs: v1 , v8 |
ecs: disabled |
---|---|---|
Source Metadata from the TCP connection on which events are being received, including the sender’s name, ip, and outbound port. |
[@metadata][input][tcp][source][name] |
[host] |
[@metadata][input][tcp][source][ip] |
[@metadata][ip_address] |
|
[@metadata][input][tcp][source][port] |
[port] |
|
Proxy Metadata from a proxied TCP connection.
Available when receiving events by proxy and
|
[@metadata][input][tcp][proxy][ip] |
[proxy_host] |
[@metadata][input][tcp][proxy][port] |
[proxy_port] |
|
SSL Subject Metadata from a secured TCP
connection. Available when |
[@metadata][input][tcp][ssl][subject] |
[sslsubject] |
For example, the Elastic Common Schema reserves the top-level host
field for information about the host on which the event happened.
If an event is missing this metadata, it can be copied into place from the source TCP connection metadata that has been added to the event:
filter { if [@metadata][input][tcp][source] and ![host] { mutate { copy => { "[@metadata][input][tcp][source][name]" => "[host][name]" "[@metadata][input][tcp][source][ip]" => "[host][ip]" } } } }
Tcp Input Configuration Options
editThis plugin supports the following configuration options plus the Common options described later.
Setting | Input type | Required |
---|---|---|
No |
||
No |
||
No |
||
string, one of |
No |
|
Yes |
||
No |
||
a valid filesystem path |
Deprecated |
|
a valid filesystem path |
No |
|
No |
||
No |
||
string, one of |
No |
|
Deprecated |
||
No |
||
No |
||
a valid filesystem path |
No |
|
No |
||
No |
||
string, one of |
No |
|
Deprecated |
||
No |
Also see Common options for a list of options supported by all input plugins.
dns_reverse_lookup_enabled
edit- Value type is boolean
-
Default value is
true
It is possible to avoid DNS reverse-lookups by disabling this setting. If disabled, the address metadata that is added to events will contain the source address as-specified at the TCP layer and IPs will not be resolved to hostnames.
ecs_compatibility
edit- Value type is string
-
Supported values are:
-
disabled
: unstructured connection metadata added at root level -
v1
,v8
: structured connection metadata added under[@metadata][input][tcp]
-
-
Default value depends on which version of Logstash is running:
-
When Logstash provides a
pipeline.ecs_compatibility
setting, its value is used as the default -
Otherwise, the default value is
disabled
.
-
When Logstash provides a
Controls this plugin’s compatibility with the Elastic Common Schema (ECS). The value of this setting affects the placement of a TCP connection’s metadata on events.
host
edit- Value type is string
-
Default value is
"0.0.0.0"
When mode is server
, the address to listen on.
When mode is client
, the address to connect to.
mode
edit-
Value can be any of:
server
,client
-
Default value is
"server"
Mode to operate in. server
listens for client connections,
client
connects to a server.
port
edit- This is a required setting.
- Value type is number
- There is no default value for this setting.
When mode is server
, the port to listen on.
When mode is client
, the port to connect to.
proxy_protocol
edit- Value type is boolean
-
Default value is
false
Proxy protocol support, only v1 is supported at this time http://www.haproxy.org/download/1.5/doc/proxy-protocol.txt
ssl_cert
editDeprecated in 6.4.0.
Replaced by ssl_certificate
- Value type is path
- There is no default value for this setting.
Path to certificate in PEM format. This certificate will be presented to the connecting clients.
ssl_certificate
edit- Value type is path
- There is no default value for this setting.
Path to certificate in PEM format. This certificate will be presented to the other part of the TLS connection.
ssl_certificate_authorities
edit- Value type is array
-
Default value is
[]
Validate client certificate or certificate chain against these authorities. You can define multiple files or paths. All the certificates will be read and added to the trust store.
ssl_cipher_suites
edit- Value type is string
- Default value includes all cipher suites enabled by the JDK and depends on JDK configuration
Supported cipher suites vary depending on Java version used, and entries look like TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384
.
For more information, see Oracle’s JDK SunJSSE provider documentation and
the table of supported Java cipher suite names.
To check the supported cipher suites locally run the following script: $LS_HOME/bin/ruby -e 'p javax.net.ssl.SSLServerSocketFactory.getDefault.getSupportedCipherSuites'
.
ssl_client_authentication
edit-
Value can be any of:
none
,optional
,required
-
Default value is
required
Controls the server’s behavior in regard to requesting a certificate from client connections:
none
disables the client authentication. required
forces a client to present a certificate, while optional
requests a client certificate
but the client is not required to present one.
When mutual TLS is enabled (optional
or required
), the certificate presented by the client must be signed by trusted
ssl_certificate_authorities
(CAs).
Please note that the server does not validate the client certificate CN (Common Name) or SAN (Subject Alternative Name).
This setting can be used only if mode
is server
and ssl_certificate_authorities
is set.
ssl_enable
editDeprecated in 6.4.0.
Replaced by ssl_enabled
- Value type is boolean
-
Default value is
false
Enable SSL (must be set for other ssl_
options to take effect).
ssl_enabled
edit- Value type is boolean
-
Default value is
false
Enable SSL (must be set for other ssl_
options to take effect).
ssl_extra_chain_certs
edit- Value type is array
-
Default value is
[]
An Array of paths to extra X509 certificates. These are used together with the certificate to construct the certificate chain presented to the client.
ssl_key
edit- Value type is path
- There is no default value for this setting.
The path to the private key corresponding to the specified certificate (PEM format).
ssl_key_passphrase
edit- Value type is password
-
Default value is
nil
SSL key passphrase for the private key.
ssl_supported_protocols
edit- Value type is string
-
Allowed values are:
'TLSv1.1'
,'TLSv1.2'
,'TLSv1.3'
-
Default depends on the JDK being used. With up-to-date Logstash, the default is
['TLSv1.2', 'TLSv1.3']
.'TLSv1.1'
is not considered secure and is only provided for legacy applications.
List of allowed SSL/TLS versions to use when establishing a secure connection.
If you configure the plugin to use 'TLSv1.1'
on any recent JVM, such as the one packaged with Logstash,
the protocol is disabled by default and needs to be enabled manually by changing jdk.tls.disabledAlgorithms
in
the $JDK_HOME/conf/security/java.security configuration file. That is, TLSv1.1
needs to be removed from the list.
ssl_verification_mode
edit-
Value can be any of:
full
,none
-
Default value is
full
Defines how to verify the certificates presented by another party in the TLS connection:
full
validates that the server certificate has an issue date that’s within
the not_before and not_after dates; chains to a trusted Certificate Authority (CA), and
has a hostname or IP address that matches the names within the certificate.
none
performs no certificate validation.
This setting can be used only if mode
is client
.
Setting certificate verification to none
disables many security benefits of SSL/TLS, which is very dangerous. For more information on disabling certificate verification please read https://www.cs.utexas.edu/~shmat/shmat_ccs12.pdf
ssl_verify
editDeprecated in 6.4.0.
Replaced by ssl_client_authentication
and ssl_verification_mode
- Value type is boolean
-
Default value is
true
Verify the identity of the other end of the SSL connection against the CA.
For input, sets the field sslsubject
to that of the client certificate.
Common options
editThese configuration options are supported by all input plugins:
Setting | Input type | Required |
---|---|---|
No |
||
No |
||
No |
||
No |
||
No |
||
No |
codec
edit- Value type is codec
-
Default value is
"line"
The codec used for input data. Input codecs are a convenient method for decoding your data before it enters the input, without needing a separate filter in your Logstash pipeline.
enable_metric
edit- Value type is boolean
-
Default value is
true
Disable or enable metric logging for this specific plugin instance by default we record all the metrics we can, but you can disable metrics collection for a specific plugin.
id
edit- Value type is string
- There is no default value for this setting.
Add a unique ID
to the plugin configuration. If no ID is specified, Logstash will generate one.
It is strongly recommended to set this ID in your configuration. This is particularly useful
when you have two or more plugins of the same type, for example, if you have 2 tcp inputs.
Adding a named ID in this case will help in monitoring Logstash when using the monitoring APIs.
input { tcp { id => "my_plugin_id" } }
Variable substitution in the id
field only supports environment variables
and does not support the use of values from the secret store.
tags
edit- Value type is array
- There is no default value for this setting.
Add any number of arbitrary tags to your event.
This can help with processing later.
type
edit- Value type is string
- There is no default value for this setting.
Add a type
field to all events handled by this input.
Types are used mainly for filter activation.
The type is stored as part of the event itself, so you can also use the type to search for it in Kibana.
If you try to set a type on an event that already has one (for example when you send an event from a shipper to an indexer) then a new input will not override the existing type. A type set at the shipper stays with that event for its life even when sent to another Logstash server.