UNS (Output)

Works exclusively with UMH Core

1 Quick-start (99 % of users)

pipeline:
  processors:
    - tag_processor:            # or Bloblang / Node-RED JS
        defaults: |
          // Minimal example
          msg.meta.location_path = "enterprise.plant1.machiningArea.cnc-line.cnc5.plc123";
          msg.meta.data_contract = "_historian";
          msg.meta.tag_name      = "value";
          // tag_processor now auto-creates msg.meta.umh_topic
          return msg;

output:
  uns: {}                       # nothing else needed on UMH Core. Will automatically use msg.meta.umh_topic from the tag_processor and write to the internal redpanda.

Open the Tag Browser (Management Console → Unified Namespace) to watch the live values.

2 - Optional overrides

output:
  uns:
    umh_topic:      "${! meta(\"umh_topic\") }"   # Must follow `umh.v1.<…>` naming. If not specified, will take the `umh_topic` from the metadata fields (e.g., from msg.meta.umh_topic)
    bridged_by:     "umh-core"                    # Traceability header. Default `umh-core`; overridden automatically by protocol-converters inside UMH Core.

3 - What the plugin does behind the scenes

1. Batching 100 messages or 100 ms – whichever comes first.

2. Sanitising Illegal chars in the key become "_".

3. Kafka/Redpanda Each message will be stored in the Kafka topic umh.messages with the Kafka key of the umh_topic

4. Headers All Benthos metadata (except kafka_*) plus bridged_by are forwarded as Kafka headers.

5. Topic check If umh.messages is missing the plugin creates it (1 partition, compact,delete).

Troubleshooting / FAQs

• "topic is not set or is empty" – your pipeline never wrote msg.meta.umh_topic. Add a tag_processor (auto) or a Bloblang line:meta umh_topic = "umh.v1.demo.plant1.line1._historian.temperature"

• I am not using umh-core, but I still want to use the uns output plugin. How can I do that? - there is a configuration variable called broker_address which you can point to any redpanda broker.