add support for plain text in payload (i.e. no JSON)

[jpmens]

this permits something like condition: event.payload == 'hello' for an MQTT publish with a payload consisting of the word "hello"

mosquitto_pub -t anomaly-data-out -m hello

[jpmens]

Rulebook fragment:

    - name: Say hello
      condition: event.payload == 'hello'
      action:
        run_module:
           name: debug
           module_args:
              msg: "Hello there from MQTT!"

[kubealex]

thank you @jpmens for the suggestion!

i have a couple of concerns about this:

• Are you aware of a use case where a plain text payload could make sense? (it would require per-string parsing)
• Couldn't this open up to potential errors for malformed json payload?

For the second one, my biggest fear is that if for any reason the source generates a malformed json payload, it would still be accepted as plaintext, increasing the debug time.

Let me know what you think :)

[jpmens]

I don't disagree that this opens the case for JSON not being parsed properly, but on the flip side, debugging that can be just as hard as having an incorrect element in the published JSON. :)

There have been several IoT devices which post plain text payloads, and adding support for plain text arguably makes it simpler for people to test.