Replace @timestamp with actual timestamp from log file

#------------------------------ Log prospector --------------------------------
- input_type: log
 file is defined twice as this can lead to unexpected behaviour.
  paths:
    - /var/log/my-log.json


  ### JSON configuration

  # Decode JSON options. Enable this if your logs are structured in JSON.
  # JSON key on which to apply the line filtering and multiline settings. This key
  # must be top level and its value must be string, otherwise it is ignored. If
  # no text key is defined, the line filtering and multiline features cannot be used.
  #json.message_key:
  json.message_key: message

  # By default, the decoded JSON is placed under a "json" key in the output document.
  # If you enable this setting, the keys are copied top level in the output document.
  #json.keys_under_root: false
  json.keys_under_root: true

  # If keys_under_root and this setting are enabled, then the values from the decoded
  # JSON object overwrite the fields that Filebeat normally adds (type, source, offset, etc.)
  # in case of conflicts.
  #json.overwrite_keys: false

  # If this setting is enabled, Filebeat adds a "json_error" key in case of JSON
  # unmarshaling errors or when a text key is defined in the configuration but cannot
  # be used.
  #json.add_error_key: false

 
#------------------------------- Redis output ---------------------------------
output.redis:
  # Boolean flag to enable or disable the output module.
  enabled: true

  # The list of Redis servers to connect to. If load balancing is enabled, the
  # events are distributed to the servers in the list. If one server becomes
  # unreachable, the events are distributed to the reachable servers only.
  hosts: ["10.10.10.20"]

  # The Redis port to use if hosts does not contain a port number. The default
  # is 6379.
  #port: 6379

  # The name of the Redis list or channel the events are published to. The
  # default is filebeat.
  #key: filebeat
  key: my-test

I've omitted most commented out lines.