Settings filter

• type: producer_consumer
• input: any kind of message
• output: same message type as input

This is a producer and consumer block that filters messages that get rejected by the filter script.

This block supports Lua 5.2 scripts ( luerl scripting engine is used under the hood). The incoming message will be provided to the script as message.

Properties

• script: The Lua script used to filter incoming messages. (required, string)

script

script

The Lua script that will determine if the message has to be discarded or allowed through. The script must return boolean value. When the returned value is true, the input massage passes through the filter to the next block in the pipeline. On the other hand, when the returning value is false, the message is dropped. If the return value is invalid or if an error occurs, the message is also dropped.

An example script would be

"""
return message.data > 0;
"""

If the message data is greater than zero, the returned value will be true allowing the message to preceed onward.

See also luerl documentation.

Examples

The following example uses filter to drop any message that does not contain test as message key

[...]
| filter
    .script("""
            return string.find(message.key, "test") ~= nil;
            """)
[...]