From fef9154ea4c587679539c30b7c255fde084e965f Mon Sep 17 00:00:00 2001
From: David Sauer <davedamoon@gmail.com>
Date: Thu, 17 Feb 2022 17:22:02 +0100
Subject: [PATCH] stop 'kubectl port-forward' when the parent process (d8s)
 exits

---
 pkg/run.go | 53 +++++++++++++++++++++++++++++++++++------------------
 pkg/up.go  |  7 +++----
 2 files changed, 38 insertions(+), 22 deletions(-)

diff --git a/pkg/run.go b/pkg/run.go
index 7b99853f..5920c2df 100644
--- a/pkg/run.go
+++ b/pkg/run.go
@@ -2,6 +2,7 @@ package d8s
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"log"
 	"net"
@@ -32,12 +33,11 @@ func Run(ctx context.Context, allowContext string, command []string) error {
 		return fmt.Errorf("select free local port: %v", err)
 	}
 
-	go portForwardForever(ctx, localPort, dindPort)
-
-	err = awaitPortOpen(ctx, localPort)
+	cancel, err := startPortForward(ctx, localPort, dindPort)
 	if err != nil {
-		return fmt.Errorf("wait for port forward to start: %v", err)
+		return fmt.Errorf("starting port-forward: %v", err)
 	}
+	defer cancel()
 
 	// execute command
 	err = executeCommand(ctx, command, fmt.Sprintf("tcp://127.0.0.1:%d", localPort))
@@ -85,23 +85,40 @@ func freePort() (int, error) {
 	return l.Addr().(*net.TCPAddr).Port, nil
 }
 
-func portForwardForever(ctx context.Context, localPort, dindPort int) {
-	err := portForward(ctx, localPort, dindPort)
-	if err != nil {
-		log.Printf("port forward failed: %v", err)
-	}
-
-	for {
-		select {
-		case <-ctx.Done():
-			return
-		case <-time.After(10 * time.Millisecond):
-			err := portForward(ctx, localPort, dindPort)
-			if err != nil {
-				log.Printf("port forward failed: %v", err)
+func startPortForward(ctx context.Context, localPort, dindPort int) (func(), error) {
+	ctx, cancel := context.WithCancel(ctx)
+	done := make(chan interface{})
+
+	go func() {
+		defer func() {
+			done <- struct{}{}
+		}()
+
+		for {
+			select {
+			case <-ctx.Done():
+				return
+			case <-time.After(10 * time.Millisecond):
+				err := portForward(ctx, localPort, dindPort)
+				isDone := len(ctx.Done()) > 0 || errors.Is(ctx.Err(), context.Canceled)
+
+				if err != nil && !isDone {
+					log.Printf("port forward failed: %v", err)
+				}
 			}
 		}
+	}()
+
+	err := awaitPortOpen(ctx, localPort)
+	if err != nil {
+		cancel()
+		return nil, fmt.Errorf("wait for port forward to start: %v", err)
 	}
+
+	return func() {
+		cancel()
+		<-done
+	}, nil
 }
 
 func portForward(ctx context.Context, localPort, dinnerPort int) error {
diff --git a/pkg/up.go b/pkg/up.go
index c28a398a..c82aa5a5 100644
--- a/pkg/up.go
+++ b/pkg/up.go
@@ -39,12 +39,11 @@ func Up(ctx context.Context, allowContext string, command []string) error {
 		return fmt.Errorf("select free local port: %v", err)
 	}
 
-	go portForwardForever(ctx, localPort, dindPort)
-
-	err = awaitPortOpen(ctx, localPort)
+	cancel, err := startPortForward(ctx, localPort, dindPort)
 	if err != nil {
-		return fmt.Errorf("wait for port forward to start: %v", err)
+		return fmt.Errorf("starting port-forward: %v", err)
 	}
+	defer cancel()
 
 	// execute command
 	err = executeCommand(ctx, command, fmt.Sprintf("tcp://127.0.0.1:%d", localPort))