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,
}

Field	Description
count	Count of all messages with the same topic
numcount	Count of all messages with numeric payload with the same topic

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".