Log Fields

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Details about the event’s logging mechanism or logging transport.

The log.* fields are typically populated with details about the logging mechanism used to create and/or transport the event. For example, syslog details belong under log.syslog.*.

The details specific to your event source are typically not logged under log.*, but rather in event.* or in other ECS fields.

Log Field Details

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Field Description Level

log.file.path

Full path to the log file this event came from, including the file name. It should include the drive letter, when appropriate.

If the event wasn’t read from a log file, do not populate this field.

type: keyword

example: /var/log/fun-times.log

OTel Badge relation log.file.path

extended

log.level

Original log level of the log event.

If the source of the event provides a log level or textual severity, this is the one that goes in log.level. If your source doesn’t specify one, you may put your event transport’s severity here (e.g. Syslog severity).

Some examples are warn, err, i, informational.

type: keyword

example: error

OTel Badge relation severity_text

core

log.logger

The name of the logger inside an application. This is usually the name of the class which initialized the logger, or can be a custom name.

type: keyword

example: org.elasticsearch.bootstrap.Bootstrap

core

log.origin.file.line

The line number of the file containing the source code which originated the log event.

type: long

example: 42

extended

log.origin.file.name

The name of the file containing the source code which originated the log event.

Note that this field is not meant to capture the log file. The correct field to capture the log file is log.file.path.

type: keyword

example: Bootstrap.java

extended

log.origin.function

The name of the function or method which originated the log event.

type: keyword

example: init

extended

log.syslog

The Syslog metadata of the event, if the event was transmitted via Syslog. Please see RFCs 5424 or 3164.

type: object

extended

log.syslog.appname

The device or application that originated the Syslog message, if available.

type: keyword

example: sshd

extended

log.syslog.facility.code

The Syslog numeric facility of the log event, if available.

According to RFCs 5424 and 3164, this value should be an integer between 0 and 23.

type: long

example: 23

extended

log.syslog.facility.name

The Syslog text-based facility of the log event, if available.

type: keyword

example: local7

extended

log.syslog.hostname

The hostname, FQDN, or IP of the machine that originally sent the Syslog message. This is sourced from the hostname field of the syslog header. Depending on the environment, this value may be different from the host that handled the event, especially if the host handling the events is acting as a collector.

type: keyword

example: example-host

extended

log.syslog.msgid

An identifier for the type of Syslog message, if available. Only applicable for RFC 5424 messages.

type: keyword

example: ID47

extended

log.syslog.priority

Syslog numeric priority of the event, if available.

According to RFCs 5424 and 3164, the priority is 8 * facility + severity. This number is therefore expected to contain a value between 0 and 191.

type: long

example: 135

extended

log.syslog.procid

The process name or ID that originated the Syslog message, if available.

type: keyword

example: 12345

extended

log.syslog.severity.code

The Syslog numeric severity of the log event, if available.

If the event source publishing via Syslog provides a different numeric severity value (e.g. firewall, IDS), your source’s numeric severity should go to event.severity. If the event source does not specify a distinct severity, you can optionally copy the Syslog severity to event.severity.

type: long

example: 3

extended

log.syslog.severity.name

The Syslog numeric severity of the log event, if available.

If the event source publishing via Syslog provides a different severity value (e.g. firewall, IDS), your source’s text severity should go to log.level. If the event source does not specify a distinct severity, you can optionally copy the Syslog severity to log.level.

type: keyword

example: Error

extended

log.syslog.structured_data

Structured data expressed in RFC 5424 messages, if available. These are key-value pairs formed from the structured data portion of the syslog message, as defined in RFC 5424 Section 6.3.

type: flattened

extended

log.syslog.version

The version of the Syslog protocol specification. Only applicable for RFC 5424 messages.

type: keyword

example: 1

extended