CORAL WIKI
Actors
Getting started
Overview
StatsActor
The StatsActor (statistics actor) is a Coral Actor that gathers a single real valued measurement from a stream of events. It saves a number of statistics as state.
Creating a StatsActor
The creation JSON of the stats actor (see Coral Actor) has "type": "stats".
The params value is a JSON with a single field:
| field | type | required | description |
|---|---|---|---|
field |
string | yes | the name of the field in the trigger-JSON to monitor |
Example
{
"data": {
"type": "actors",
"attributes": {
"type": "stats",
"params": {
"field": "amount"
},
"group": {
"by": "tag"
}
}
}
}This will create a statistics component monitoring the field amount. Each different value for the field tag will have a separate state.
Trigger
The StatsActor only does useful work if the trigger is connected.
The actor gathers values supplied by the field specified in the parameters.
Emit
The StatsActor emits nothing. Only the state provides information.
State
The StatsActor keeps the following summary statistics as state:
| field | type | description |
|---|---|---|
count |
integer | number of values processed |
avg |
float | the average value |
sd |
float | the (population) standard deviation |
min |
float | the minimum value |
max |
float | the maximum value |
The state is updated every time a value for the specified field is encountered in the trigger.
Note that when no events have occurred the count is zero, and other fields are undefined. This is represented as null in the JSON representation of the state.
Collect
The StatsActor does not collect state from other actors.
Timer
The StatsActor does not provide timer actions.