mutate

If this filter is successful, add any arbitrary fields to this event. Field names can be dynamic and include parts of the event using the %{field}.

Example:

    filter {
      mutate {
        add_field => { "foo_%{somefield}" => "Hello world, from %{host}" }
      }
    }
[source,ruby]
    # You can also add multiple fields at once:
    filter {
      mutate {
        add_field => {
          "foo_%{somefield}" => "Hello world, from %{host}"
          "new_field" => "new_static_value"
        }
      }
    }

If the event has field "somefield" == "hello" this filter, on success, would add field foo_hello if it is present, with the value above and the %{host} piece replaced with that value from the event. The second example would also add a hardcoded field.

If this filter is successful, add arbitrary tags to the event. Tags can be dynamic and include parts of the event using the %{field} syntax.

Example:

    filter {
      mutate {
        add_tag => [ "foo_%{somefield}" ]
      }
    }
[source,ruby]
    # You can also add multiple tags at once:
    filter {
      mutate {
        add_tag => [ "foo_%{somefield}", "taggedy_tag"]
      }
    }

If the event has field "somefield" == "hello" this filter, on success, would add a tag foo_hello (and the second example would of course add a taggedy_tag tag).

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.

If the conversion type is boolean, the acceptable values are:

If a value other than these is provided, it will pass straight through and log a warning message.

Valid conversion targets are: integer, float, string, and boolean.

Example:

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

Convert a string field by applying a regular expression and a replacement. If the field is not a string, 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 an array with a separator character. Does nothing on non-array fields.

Example:

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

Convert a string to its lowercase equivalent.

Example:

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

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" }
      }
    }

Call the filter flush method at regular interval. Optional.

Remove one or more fields.

Example:

    filter {
      mutate {
        remove => [ "client" ]  # Removes the 'client' field
      }
    }

This option is deprecated, instead use remove_field option available in all filters.

If this filter is successful, remove arbitrary fields from this event. Fields names can be dynamic and include parts of the event using the %{field} Example:

    filter {
      mutate {
        remove_field => [ "foo_%{somefield}" ]
      }
    }
[source,ruby]
    # You can also remove multiple fields at once:
    filter {
      mutate {
        remove_field => [ "foo_%{somefield}", "my_extraneous_field" ]
      }
    }

If the event has field "somefield" == "hello" this filter, on success, would remove the field with name foo_hello if it is present. The second example would remove an additional, non-dynamic field.

If this filter is successful, remove arbitrary tags from the event. Tags can be dynamic and include parts of the event using the %{field} syntax.

Example:

    filter {
      mutate {
        remove_tag => [ "foo_%{somefield}" ]
      }
    }
[source,ruby]
    # You can also remove multiple tags at once:
    filter {
      mutate {
        remove_tag => [ "foo_%{somefield}", "sad_unwanted_tag"]
      }
    }

If the event has field "somefield" == "hello" this filter, on success, would remove the tag foo_hello if it is present. The second example would remove a sad, unwanted tag as well.

Rename one or more fields.

Example:

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

Replace a field with a new value. 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 a field to an array using a separator character. Only works on string fields.

Example:

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

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

Example:

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

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" }
      }
    }

Convert a string to its uppercase equivalent.

Example:

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