go(utils): add command util for printing output with stdout pipe

go/commands/yarn.go

@@ -0,0 +1,15 @@
+package commands
+
+import (
+	"ocl/portainer-devtool/utils"
+)
+
+// RunClient starts the portainer client
+func RunPortainerClient(workdir string) error {
+	err := utils.RunCommandWithStdoutPipe(workdir, "yarn")
+	if err != nil {
+		return err
+	}
+
+	return utils.RunCommandWithStdoutPipe(workdir, "yarn", "start:client")
+}

go/utils/command.go

@@ -0,0 +1,45 @@
+package utils
+
+import (
+	"bufio"
+	"fmt"
+	"os/exec"
+)
+
+func RunCommandWithStdoutPipe(workdir, progName string, args ...string) error {
+	cmd := exec.Command(progName, args...)
+	cmd.Dir = workdir
+	out, err := cmd.StdoutPipe()
+	if err != nil {
+		return err
+	}
+
+	scanner := bufio.NewScanner(out)
+	go func() {
+		counter := 0
+		for scanner.Scan() {
+			if counter > 10 {
+				// Swallow the output
+				if counter%50 == 0 {
+					fmt.Printf("output %d lines in total.\n", counter)
+				}
+				counter++
+				continue
+			}
+			PrintOutput("", scanner.Bytes())
+			counter++
+		}
+	}()
+
+	err = cmd.Start()
+	if err != nil {
+		return err
+	}
+
+	err = cmd.Wait()
+	if err != nil {
+		return err
+	}
+
+	return nil
+}