The alter filter allows you to do general alterations to fields that are not included in the normal mutate filter.
NOTE: The functionality provided by this plugin is likely to be merged into the ‘mutate’ filter in future versions.
filter {
alter {
add_field => ... # hash (optional), default: {}
add_tag => ... # array (optional), default: []
coalesce => ... # array (optional)
condrewrite => ... # array (optional)
condrewriteother => ... # array (optional)
remove_field => ... # array (optional), default: []
remove_tag => ... # array (optional), default: []
}
}
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 {
alter {
add_field => { "foo_%{somefield}" => "Hello world, from %{host}" }
}
}
# You can also add multiple fields at once:
filter {
alter {
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 {
alter {
add_tag => [ "foo_%{somefield}" ]
}
}
# You can also add multiple tags at once:
filter {
alter {
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).
Sets the value of field_name to the first nonnull expression among its arguments.
Example:
filter {
alter {
coalesce => [
"field_name", "value1", "value2", "value3", ...
]
}
}
Change the content of the field to the specified value if the actual content is equal to the expected one.
Example:
filter {
alter {
condrewrite => [
"field_name", "expected_value", "new_value",
"field_name2", "expected_value2, "new_value2",
....
]
}
}
Change the content of the field to the specified value if the content of another field is equal to the expected one.
Example:
filter {
alter {
condrewriteother => [
"field_name", "expected_value", "field_name_to_change", "value",
"field_name2", "expected_value2, "field_name_to_change2", "value2",
....
]
}
}
Only handle events without all/any (controlled by exclude_any config option) of these tags. Optional.
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 {
alter {
remove_field => [ "foo_%{somefield}" ]
}
}
# You can also remove multiple fields at once:
filter {
alter {
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 {
alter {
remove_tag => [ "foo_%{somefield}" ]
}
}
# You can also remove multiple tags at once:
filter {
alter {
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.
Only handle events with all/any (controlled by include_any config option) of these tags. Optional.
Note that all of the specified routing options (type,tags.exclude_tags,include_fields,exclude_fields) must be met in order for the event to be handled by the filter. The type to act on. If a type is given, then this filter will only act on messages with the same type. See any input plugin’s “type” attribute for more. Optional.