opensearch-docs-cn/_data-prepper/pipelines/configuration/processors/grok.md

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grok

The Grok processor takes unstructured data and utilizes pattern matching to structure and extract important keys.

Configuration

The following table describes options you can use with the Grok processor to structure your data and make your data easier to query.

Option	Required	Type	Description
match	No	Map	Specifies which keys to match specific patterns against. Default value is an empty body.
keep_empty_captures	No	Boolean	Enables preserving null captures. Default value is false.
named_captures_only	No	Boolean	Specifies whether to keep only named captures. Default value is true.
break_on_match	No	Boolean	Specifies whether to match all patterns or stop once the first successful match is found. Default value is true.
keys_to_overwrite	No	List	Specifies which existing keys will be overwritten if there is a capture with the same key value. Default value is [].
pattern_definitions	No	Map	Allows for custom pattern use inline. Default value is an empty body.
patterns_directories	No	List	Specifies the path of directories that contain customer pattern files. Default value is an empty list.
pattern_files_glob	No	String	Specifies which pattern files to use from the directories specified for pattern_directories. Default value is *.
target_key	No	String	Specifies a parent-level key used to store all captures. Default value is null.
timeout_millis	No	Integer	The maximum amount of time during which matching occurs. Setting to 0 disables the timeout. Default value is 30,000.

Metrics

The following table describes common Abstract processor metrics.

Metric name	Type	Description
recordsIn	Counter	Metric representing the ingress of records to a pipeline component.
recordsOut	Counter	Metric representing the egress of records from a pipeline component.
timeElapsed	Timer	Metric representing the time elapsed during execution of a pipeline component.

The Grok processor includes the following custom metrics.

Counter

• grokProcessingMismatch: Records the number of records that did not match any of the patterns specified in the match field.
• grokProcessingMatch: Records the number of records that matched at least one pattern from the match field.
• grokProcessingErrors: Records the total number of record processing errors.
• grokProcessingTimeouts: Records the total number of records that timed out while matching.

Timer

• grokProcessingTime: The time taken by individual records to match against patterns from match. The avg metric is the most useful metric for this timer because it provides you with an average value of the time it takes records to match.