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".