Expect

Testing records to ensure they contain an expected key and values

The expect filter plugin lets you validate that records match certain criteria in their structure, like validating that a key exists or it has a specific value.

For a detailed explanation of its usage and use cases, see Validating and your Data and Structure.

Configuration parameters

The plugin supports the following configuration parameters:

Property	Description
key_exists	Check if a key with a given name exists in the record.
key_not_exists	Check if a key doesn't exist in the record.
key_val_is_null	Check that the value of the key is NULL.
key_val_is_not_null	Check that the value of the key is NOT NULL.
key_val_eq	Check that the value of the key equals the given value in the configuration.
action	Action to take when a rule doesn't match. Available options are warn , exit or result_key. On warn, a warning message is sent to the logging layer when a mismatch of the key* rules is found. Using exit makes Fluent Bit exit with status code 255. result_key adds a matching result to each record.
result_key	Specify a key name for the matching result added when action is set to result_key.