:plugin: log4j
:type: input

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:version: %VERSION%
:release_date: %RELEASE_DATE%
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:include_path: ../../../../logstash/docs/include
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[id="plugins-{type}s-{plugin}"]

=== Log4j input plugin

include::{include_path}/plugin_header.asciidoc[]

==== Deprecation Notice

NOTE: This plugin is deprecated. It is recommended that you use filebeat to collect logs from log4j.

The following section is a guide for how to migrate from SocketAppender to use filebeat.

To migrate away from log4j SocketAppender to using filebeat, you will need to make 3 changes:

1) Configure your log4j.properties (in your app) to write to a local file.
2) Install and configure filebeat to collect those logs and ship them to Logstash
3) Configure Logstash to use the beats input.

.Configuring log4j for writing to local files

In your log4j.properties file, remove SocketAppender and replace it with RollingFileAppender. 

For example, you can use the following log4j.properties configuration to write daily log files.

    # Your app's log4j.properties (log4j 1.2 only)
    log4j.rootLogger=daily
    log4j.appender.daily=org.apache.log4j.rolling.RollingFileAppender
    log4j.appender.daily.RollingPolicy=org.apache.log4j.rolling.TimeBasedRollingPolicy
    log4j.appender.daily.RollingPolicy.FileNamePattern=/var/log/your-app/app.%d.log
    log4j.appender.daily.layout = org.apache.log4j.PatternLayout
    log4j.appender.daily.layout.ConversionPattern=%d{YYYY-MM-dd HH:mm:ss,SSSZ} %p %c{1}:%L - %m%n

Configuring log4j.properties in more detail is outside the scope of this migration guide.

.Configuring filebeat

Next,
https://www.elastic.co/guide/en/beats/filebeat/current/filebeat-installation.html[install
filebeat]. Based on the above log4j.properties, we can use this filebeat
configuration:

    # filebeat.yml
    filebeat:
      prospectors:
        -
          paths:
            - /var/log/your-app/app.*.log
          input_type: log
    output:
      logstash:
        hosts: ["your-logstash-host:5000"]

For more details on configuring filebeat, see 
https://www.elastic.co/guide/en/beats/filebeat/current/filebeat-configuration.html[the filebeat configuration guide].

.Configuring Logstash to receive from filebeat

Finally, configure Logstash with a beats input:

    # logstash configuration
    input {
      beats {
        port => 5000
      }
    }

It is strongly recommended that you also enable TLS in filebeat and logstash
beats input for protection and safety of your log data..

For more details on configuring the beats input, see
https://www.elastic.co/guide/en/logstash/current/plugins-inputs-beats.html[the logstash beats input documentation].

==== Description

Read events over a TCP socket from a Log4j SocketAppender. This plugin works only with log4j version 1.x.

Can either accept connections from clients or connect to a server,
depending on `mode`. Depending on which `mode` is configured,
you need a matching SocketAppender or a SocketHubAppender
on the remote side.

One event is created per received log4j LoggingEvent with the following schema:

* `timestamp` => the number of milliseconds elapsed from 1/1/1970 until logging event was created.
* `path` => the name of the logger
* `priority` => the level of this event
* `logger_name` => the name of the logger
* `thread` => the thread name making the logging request
* `class` => the fully qualified class name of the caller making the logging request.
* `file` => the source file name and line number of the caller making the logging request in a colon-separated format "fileName:lineNumber".
* `method` => the method name of the caller making the logging request.
* `NDC` => the NDC string
* `stack_trace` => the multi-line stack-trace

Also if the original log4j LoggingEvent contains MDC hash entries, they will be merged in the event as fields.

[id="plugins-{type}s-{plugin}-options"]
==== Log4j Input Configuration Options

This plugin supports the following configuration options plus the <<plugins-{type}s-{plugin}-common-options>> described later.

[cols="<,<,<",options="header",]
|=======================================================================
|Setting |Input type|Required
| <<plugins-{type}s-{plugin}-host>> |<<string,string>>|No
| <<plugins-{type}s-{plugin}-mode>> |<<string,string>>, one of `["server", "client"]`|No
| <<plugins-{type}s-{plugin}-port>> |<<number,number>>|No
| <<plugins-{type}s-{plugin}-proxy_protocol>> |<<boolean,boolean>>|No
|=======================================================================

Also see <<plugins-{type}s-{plugin}-common-options>> for a list of options supported by all
input plugins.

&nbsp;

[id="plugins-{type}s-{plugin}-host"]
===== `host` 

  * Value type is <<string,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.

[id="plugins-{type}s-{plugin}-mode"]
===== `mode` 

  * 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.

[id="plugins-{type}s-{plugin}-port"]
===== `port` 

  * Value type is <<number,number>>
  * Default value is `4560`

When mode is `server`, the port to listen on.
When mode is `client`, the port to connect to.

[id="plugins-{type}s-{plugin}-proxy_protocol"]
===== `proxy_protocol` 

  * Value type is <<boolean,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



[id="plugins-{type}s-{plugin}-common-options"]
include::{include_path}/{type}.asciidoc[]