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package flow_test
import (
"context"
"fmt"
"log"
"cuelang.org/go/cue"
"cuelang.org/go/cue/cuecontext"
"cuelang.org/go/tools/flow"
)
func Example() {
ctx := cuecontext.New()
v := ctx.CompileString(`
a: {
input: "world"
output: string
}
b: {
input: a.output
output: string
}
`)
if err := v.Err(); err != nil {
log.Fatal(err)
}
controller := flow.New(nil, v, ioTaskFunc)
if err := controller.Run(context.Background()); err != nil {
log.Fatal(err)
}
// Output:
// setting a.output to "hello world"
// setting b.output to "hello hello world"
}
func ioTaskFunc(v cue.Value) (flow.Runner, error) {
inputPath := cue.ParsePath("input")
input := v.LookupPath(inputPath)
if !input.Exists() {
return nil, nil
}
return flow.RunnerFunc(func(t *flow.Task) error {
inputVal, err := t.Value().LookupPath(inputPath).String()
if err != nil {
return fmt.Errorf("input not of type string")
}
outputVal := fmt.Sprintf("hello %s", inputVal)
fmt.Printf("setting %s.output to %q\n", t.Path(), outputVal)
return t.Fill(map[string]string{
"output": outputVal,
})
}), nil
}
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