select channel with error handling

concurrency/goroutine_leak/main.go

@@ -20,6 +20,7 @@ goroutines in some sort of organized fashion.
 **/
 
 func main() {
+	resourceLeak()
 	cancellationSignal()
 }
 

concurrency/select_error_handling/main.go

@@ -0,0 +1,65 @@
+package main
+
+import (
+	"fmt"
+	"time"
+
+	"github.com/davecgh/go-spew/spew"
+)
+
+func main() {
+	if err := selectWithErrorDemo(); err != nil {
+		spew.Dump(err)
+	}
+	time.Sleep(time.Second * 5)
+}
+
+func selectWithErrorDemo() error {
+	// start update race and market
+	count, errChan, doneChan := 2, make(chan error), make(chan bool)
+
+	go func() {
+		// update race
+		if err := doFirstThing(); err != nil {
+			errChan <- err
+		} else {
+			doneChan <- true
+			fmt.Println("Finish First Go Routine")
+		}
+
+	}()
+
+	go func() {
+		// update market
+		if err := doSecondThing(); err != nil {
+			errChan <- err
+		} else {
+			doneChan <- true
+			fmt.Println("Finish Second Go Routine")
+		}
+	}()
+
+	for i := 0; i < count; i++ {
+		select {
+		case err := <-errChan:
+			return err
+		case d := <-doneChan:
+			spew.Dump(i, d)
+		}
+	}
+	return nil
+}
+
+func doFirstThing() error {
+	time.Sleep(time.Second * 2)
+	fmt.Println("Exectue Do First")
+	return nil
+
+}
+
+func doSecondThing() error {
+	time.Sleep(time.Second * 1)
+	fmt.Println("Exectue Do Second")
+	// return errors.New("Error In Second")
+	return nil
+}