Fix 100% CPU usage issue

Author: liamg

pkg/terminal/lazycopy.go

@@ -0,0 +1,38 @@
+package terminal
+
+import (
+	"io"
+	"time"
+)
+
+const BackOffReadInitialSleepDuration = time.Millisecond
+const BackOffReadMaxSleepDuration = time.Millisecond * 16
+
+// similar to io.Copy with sleep when no data is received
+func lazyCopy(dst io.Writer, src io.Reader) error {
+
+	buffer := make([]byte, 4096)
+
+	backOffDelay := BackOffReadInitialSleepDuration
+
+	for {
+		size, err := src.Read(buffer)
+		if size > 0 {
+			if _, err := dst.Write(buffer[:size]); err != nil {
+				return err
+			}
+			backOffDelay = BackOffReadInitialSleepDuration
+		}
+		if err != nil {
+			return err
+		}
+		if size == 0 {
+			// if there was no data to read, wait a little while before trying again
+			time.Sleep(backOffDelay)
+			backOffDelay = backOffDelay * 2
+			if backOffDelay > BackOffReadMaxSleepDuration {
+				backOffDelay = BackOffReadMaxSleepDuration
+			}
+		}
+	}
+}

pkg/terminal/terminal.go

@@ -2,7 +2,6 @@ package terminal
 
 import (
 	"fmt"
-	"io"
 	"os"
 	"os/exec"
 	"os/signal"
@@ -126,9 +125,9 @@ func (t *Terminal) Run() error {
 	defer func() { _ = terminal.Restore(int(os.Stdin.Fd()), oldState) }() // Best effort.
 
 	// Copy stdin to the pty and the pty to stdout.
-	go func() { _, _ = io.Copy(t.pty, os.Stdin) }()
-	go func() { _, _ = io.Copy(os.Stdout, t.proxy) }()
-	_, _ = io.Copy(t.proxy, t.pty)
+	go func() {  _ = lazyCopy(t.pty, os.Stdin) }()
+	go func() {  _ = lazyCopy(os.Stdout, t.proxy) }()
+	_ = lazyCopy(t.proxy, t.pty)
 	fmt.Printf("\r\n")
 	return nil
 }