node-red-contrib-metric-per-topic v0.2.0

Metric per Topic Node

Count and calculate the payload metric per topic within given interval.

Input

• Payload

  If the payload is numeric the node calculate the metric per topic. Otherwise the node only count the messages per topic.

• Control the node

  In case you want information about current message count without resetting the counter, then send message with topic "mpt-control" and payload "report". To distinguish between measure and report messages you can use msg.isReset property. This can be useful for displaying message count to a graph.

Output

The node has two outputs.

• Output 1 will generate summary message on every interval. The payload is an object with the min, max, avg, sum and count per topic.
• Output 2 will repeat incoming (non-control) messages. It can be used to continue your flow.

Outputschema

{
  "payload": {
    "<topicname1>": {
      "count": 3,
      "sum": 8,
      "numcount": 2,
      "avg": 4,
      "min": 3,
      "max": 5
    },
    "<topicname2>": {
      "count": 4
    },
    ...
  },
  "totalMessageCount": 39,
  "totalMessageInterval": 15,
}

Intervals

Messages are counted on regular intervals when a measuring message arrives. You can choose between two types of measuring message generators:

INTERNAL: uses built-in generator. You can specify interval and units (seconds / minutes / hours). Intervals can be aligned to the system clock EXTERNAL: in this case you are responsible of generating measuring messages. The topic should be "mpt-control" and the payload should be "measure".