At least one of split, replace or merge need to be set for this filter configuration to be valid. If merging does not succeed because destination field is not a string nor []string, gogstash_filter_mutate_error will be added to the event
filter:
- type: mutate
# 2 item array. First item is field to split. Second item is string to split with
split: ["mycommalistvalue", ","]
# 3 item array. First item is field to modify. Second item is value to replace. Third item is new value to replace with.
replace: ["myfield", "oldvalue", "newvalue"]
# 2 item array. First item is field to merge on. Second item is string to add to merged field
merge: ["listofthings", "newitemtoadd"]