index.asciidoc

Mutate filter plugin

../../../../logstash/docs/include/plugin_header.asciidoc

Description

The mutate filter allows you to perform general mutations on fields. You can rename, replace, and modify fields in your events.

Processing order

Mutations in a config file are executed in this order:

• coerce

• rename

• update

• replace

• convert

• gsub

• uppercase

• capitalize

• lowercase

• strip

• split

• join

• merge

• copy

Important

Each mutation must be in its own code block if the sequence of operations needs to be preserved.

Example:

filter {
    mutate {
        split => { "hostname" => "." }
        add_field => { "shortHostname" => "%{[hostname][0]}" }
    }

    mutate {
        rename => {"shortHostname" => "hostname"}
    }
}

Mutate Filter Configuration Options

This plugin supports the following configuration options plus the [plugins-filters-mutate-common-options] described later.

Setting	Input type	Required
convert	hash	No
copy	hash	No
gsub	array	No
join	hash	No
lowercase	array	No
merge	hash	No
coerce	hash	No
rename	hash	No
replace	hash	No
split	hash	No
strip	array	No
update	hash	No
uppercase	array	No
capitalize	array	No
tag_on_failure	string	No

Also see [plugins-filters-mutate-common-options] for a list of options supported by all filter plugins.

 

convert

• Value type is hash

• There is no default value for this setting.

Convert a field’s value to a different type, like turning a string to an integer. If the field value is an array, all members will be converted. If the field is a hash no action will be taken.

Note

Conversion insights The values are converted using Ruby semantics. Be aware that using float and float_eu converts the value to a double-precision 64-bit IEEE 754 floating point decimal number. In order to maintain precision due to the conversion, you should use a double in the Elasticsearch mappings.

Valid conversion targets, and their expected behaviour with different inputs are:

• integer:

  • strings are parsed; comma-separators are supported (e.g., the string "1,000" produces an integer with value of one thousand); when strings have decimal parts, they are truncated.

  • floats and decimals are truncated (e.g., 3.99 becomes 3, -2.7 becomes -2)

  • boolean true and boolean false are converted to 1 and 0 respectively

• integer_eu:

  • same as integer, except string values support dot-separators and comma-decimals (e.g., "1.000" produces an integer with value of one thousand)

• float:

  • integers are converted to floats

  • strings are parsed; comma-separators and dot-decimals are supported (e.g., "1,000.5" produces a float with value of one thousand and one half)

  • boolean true and boolean false are converted to 1.0 and 0.0 respectively

• float_eu:

  • same as float, except string values support dot-separators and comma-decimals (e.g., "1.000,5" produces a float with value of one thousand and one half)

• string:

  • all values are stringified and encoded with UTF-8

• boolean:

  • integer 0 is converted to boolean false

  • integer 1 is converted to boolean true

  • float 0.0 is converted to boolean false

  • float 1.0 is converted to boolean true

  • strings "true", "t", "yes", "y", "1"`and `"1.0" are converted to boolean true

  • strings "false", "f", "no", "n", "0" and "0.0" are converted to boolean false

  • empty strings are converted to boolean false

  • all other values pass straight through without conversion and log a warning message

  • for arrays each value gets processed separately using rules above

This plugin can convert multiple fields in the same document, see the example below.

Example:

    filter {
      mutate {
        convert => {
          "fieldname" => "integer"
          "booleanfield" => "boolean"
        }
      }
    }

copy

• Value type is hash

• There is no default value for this setting.

Copy an existing field to another field. Existing target field will be overriden.

Example:

    filter {
      mutate {
         copy => { "source_field" => "dest_field" }
      }
    }

gsub

• Value type is array

• There is no default value for this setting.

Match a regular expression against a field value and replace all matches with a replacement string. Only fields that are strings or arrays of strings are supported. For other kinds of fields no action will be taken.

This configuration takes an array consisting of 3 elements per field/substitution.

Be aware of escaping any backslash in the config file.

Example:

    filter {
      mutate {
        gsub => [
          # replace all forward slashes with underscore
          "fieldname", "/", "_",
          # replace backslashes, question marks, hashes, and minuses
          # with a dot "."
          "fieldname2", "[\\?#-]", "."
        ]
      }
    }

join

• Value type is hash

• There is no default value for this setting.

Join an array with a separator character or string. Does nothing on non-array fields.

Example:

   filter {
     mutate {
       join => { "fieldname" => "," }
     }
   }

lowercase

• Value type is array

• There is no default value for this setting.

Convert a string to its lowercase equivalent.

Example:

    filter {
      mutate {
        lowercase => [ "fieldname" ]
      }
    }

merge

• Value type is hash

• There is no default value for this setting.

Merge two fields of arrays or hashes. String fields will be automatically be converted into an array, so:

`array` + `string` will work
`string` + `string` will result in an 2 entry array in `dest_field`
`array` and `hash` will not work

Example:

    filter {
      mutate {
         merge => { "dest_field" => "added_field" }
      }
    }

coerce

• Value type is hash

• There is no default value for this setting.

Set the default value of a field that exists but is null

Example:

    filter {
      mutate {
        # Sets the default value of the 'field1' field to 'default_value'
        coerce => { "field1" => "default_value" }
      }
    }

rename

• Value type is hash

• There is no default value for this setting.

Rename one or more fields.

If the destination field already exists, its value is replaced.

If one of the source fields doesn’t exist, no action is performed for that field. (This is not considered an error; the tag_on_failure tag is not applied.)

When renaming multiple fields, the order of operations is not guaranteed.

Example:

    filter {
      mutate {
        # Renames the 'HOSTORIP' field to 'client_ip'
        rename => { "HOSTORIP" => "client_ip" }
      }
    }

replace

• Value type is hash

• There is no default value for this setting.

Replace the value of a field with a new value, or add the field if it doesn’t already exist. The new value can include %{foo} strings to help you build a new value from other parts of the event.

Example:

    filter {
      mutate {
        replace => { "message" => "%{source_host}: My new message" }
      }
    }

split

• Value type is hash

• There is no default value for this setting.

Split a field to an array using a separator character or string. Only works on string fields.

Example:

    filter {
      mutate {
         split => { "fieldname" => "," }
      }
    }

strip

• Value type is array

• There is no default value for this setting.

Strip whitespace from field. NOTE: this only works on leading and trailing whitespace.

Example:

    filter {
      mutate {
         strip => ["field1", "field2"]
      }
    }

update

• Value type is hash

• There is no default value for this setting.

Update an existing field with a new value. If the field does not exist, then no action will be taken.

Example:

    filter {
      mutate {
        update => { "sample" => "My new message" }
      }
    }

uppercase

• Value type is array

• There is no default value for this setting.

Convert a string to its uppercase equivalent.

Example:

    filter {
      mutate {
        uppercase => [ "fieldname" ]
      }
    }

capitalize

• Value type is array

• There is no default value for this setting.

Convert a string to its capitalized equivalent.

Example:

    filter {
      mutate {
        capitalize => [ "fieldname" ]
      }
    }

tag_on_failure

• Value type is string

• The default value for this setting is _mutate_error

If a failure occurs during the application of this mutate filter, the rest of the operations are aborted and the provided tag is added to the event.

../../../../logstash/docs/include/filter.asciidoc