DStream::reactiveStatelessEngine

Syntax

DStream::reactiveStatelessEngine(metrics)

Arguments

metrics is a vector of dictionaries, specifying the calculation formulas and their dependencies. Each dictionary has the following key-value pairs:
  • "outputName"->productName:metricName

  • "formula"-><expression>

    The value of formula is a metacode expression defining the formula for calculation, which can reference other variables. For example, the expression can be <A*B>, and A and B are precedent variables for this formula.

  • Key-value pairs specifying the precedent variable locations used in the formula above. For exmaple, for <A*B>, specify:

    • "A"->productName:metricName
    • "B"->productName:metricName

    The productName and metricName uniquely specify the location of the variable, which can be the input or output table.

Examples

if (!existsCatalog("orca")) {
	createCatalog("orca")
}
go
use catalog orca


// If a stream graph with the same name already exists, destroy it first.
// dropStreamGraph('engine')

g = createStreamGraph('engine')

metrics = array(ANY, 0, 0)
metric1 = dict(STRING,ANY)
// product_B:value=product_A:factor1+product_A:factor2+product_B:factor1
metric1["outputName"] = `product_B:`value
metric1["formula"] = <A+B+C>
metric1["A"] = `product_A:`factor1
metric1["B"] = `product_A:`factor2
metric1["C"] = `product_B:`factor1
metrics.append!(metric1)
// product_C:value=product_B:value*product_C:factor1
metric2 = dict(STRING, ANY)
metric2["outputName"] =`product_C:`value
metric2["formula"] = <A*B>
metric2["A"] = `product_B:`value 
metric2["B"] = `product_C:`factor1
metrics.append!(metric2)

g.source("input", 1000:0, `product`factor`value, [STRING, STRING, DOUBLE])
.reactiveStatelessEngine(metrics)
.sink("output")
g.submit()
go

products = take("product_A", 2)
factors = ["factor1", "factor2"]
values = [1.0, 2.0]
tmp = table(products as product, factors as factor, values as value)
appendOrcaStreamTable("input", tmp)

products = take("product_B", 1)
factors = take("factor1", 1)
values = take(1.0, 1)
tmp = table(products as product, factors as factor, values as value)
appendOrcaStreamTable("input", tmp)


select * from orca_table.output
productName metricName metricsResults
product_B value
product_C value
product_B value 4
product_C value