buffered channel demo

concurrency/subtasks/main.go

@@ -0,0 +1,41 @@
+package main
+
+// https://medium.com/capital-one-developers/buffered-channels-in-go-what-are-they-good-for-43703871828
+
+// One common pattern for goroutines is fan-out. When you want to apply the same data to multiple algorithms,
+// you can launch a goroutine for each subtask, and then gather the data back in when they are done.
+// For example, you might want to process the same data via multiple scoring algorithms and return back
+// all of the scores or pull data from multiple microservices to compose a single page. A buffered channel is an
+// ideal way to gather the data back from your subtasks.
+
+func main() {
+
+}
+
+type Evaluator func(interface{}) (interface{}, error)
+
+func DivideAndConquer(data interface{}, evaluators []Evaluator) ([]interface{}, []error) {
+	gather := make(chan interface{}, len(evaluators))
+	errors := make(chan error, len(evaluators))
+	for _, v := range evaluators {
+		go func(e Evaluator) {
+			result, err := e(data)
+			if err != nil {
+				errors <- err
+			} else {
+				gather <- result
+			}
+		}(v)
+	}
+	out := make([]interface{}, 0, len(evaluators))
+	errs := make([]error, 0, len(evaluators))
+	for range evaluators {
+		select {
+		case r := <-gather:
+			out = append(out, r)
+		case e := <-errors:
+			errs = append(errs, e)
+		}
+	}
+	return out, errs
+}