Add fast support for macOS

Updates #52

Still no good support for multi user systems but I think that's fine
for now.

Author: nhooyr

codeserver.go

@@ -3,9 +3,12 @@ package main
 import (
 	"context"
 	"io"
+	"net"
 	"net/http"
 	"os"
+	"os/exec"
 	"path/filepath"
+	"runtime"
 	"strings"
 	"time"
 
@@ -82,6 +85,25 @@ func codeServerPort(cntName string) (string, error) {
 	)
 
 	for ctx.Err() == nil {
+		if runtime.GOOS == "darwin" {
+			// macOS uses port forwarding instead of host networking so netstat stuff below will not work
+			// as it will find the port inside the container, which we already know is 8443.
+			cmd := exec.CommandContext(ctx, "docker", "port", cntName, "8443")
+			var out []byte
+			out, err = cmd.CombinedOutput()
+			if err != nil {
+				continue
+			}
+
+			addr := strings.TrimSpace(string(out))
+			_, port, err = net.SplitHostPort(addr)
+			if err != nil {
+				return "", xerrors.Errorf("invalid address from docker port: %q", string(out))
+			}
+
+			return port, nil
+		}
+
 		port, err = codeserver.Port(cntName)
 		if err == nil {
 			return port, nil

internal/codeserver/proc.go

@@ -130,7 +130,7 @@ func parseNetTCPStats(out []byte) ([]*netStat, error) {
 	for _, line := range lines {
 		fields := strings.Fields(string(bytes.TrimSpace(line)))
 		if len(fields) != 3 {
-			return nil, xerrors.Errorf("line formatted incorrectly: %s", line)
+			return nil, xerrors.Errorf("line formatted incorrectly: %q", line)
 		}
 
 		var stat netStat

project.go

@@ -3,7 +3,6 @@ package main
 import (
 	"context"
 	"fmt"
-	"net"
 	"os"
 	"path/filepath"
 	"strings"
@@ -247,7 +246,7 @@ func (p *project) open() error {
 		return err
 	}
 
-	u := "http://localhost:" + port
+	u := "http://127.0.0.1:" + port
 
 	flog.Info("opening %v", u)
 	return browserapp.Open(u)

runner.go

@@ -4,10 +4,10 @@ import (
 	"context"
 	"fmt"
 	"github.com/docker/go-connections/nat"
+	"log"
 	"os"
 	"path/filepath"
 	"runtime"
-	"strconv"
 	"strings"
 	"time"
 
@@ -70,17 +70,26 @@ func (r *runner) runContainer(image string) error {
 		return err
 	}
 
+	containerAddr := "localhost"
+	containerPort := r.port
+	if runtime.GOOS == "darwin" {
+		// See justification below.
+		containerPort = "8443"
+		containerAddr = "0.0.0.0"
+	}
 	// We want the code-server logs to be available inside the container for easy
 	// access during development, but also going to stdout so `docker logs` can be used
 	// to debug a failed code-server startup.
-	cmd := "cd " + projectDir +
-		"; code-server --host 127.0.0.1" +
-		" --port " + r.port +
-		" --data-dir ~/.config/Code --extensions-dir ~/.vscode/extensions --allow-http --no-auth 2>&1 | tee " + containerLogPath
+	cmd := fmt.Sprintf(`set -euxo pipefail || exit 1
+cd %v
+code-server --host %v --port %v --data-dir ~/.config/Code --extensions-dir ~/.vscode/extensions --allow-http --no-auth 2>&1 | tee %v
+`, projectDir, containerAddr, containerPort, containerLogPath)
 	if r.testCmd != "" {
 		cmd = r.testCmd + "\n exit 1"
 	}
 
+	log.Printf("%q", cmd)
+
 	var envs []string
 	sshAuthSock, exists := os.LookupEnv("SSH_AUTH_SOCK")
 	if exists {
@@ -101,10 +110,9 @@ func (r *runner) runContainer(image string) error {
 			projectLocalDirLabel: r.projectLocalDir,
 			projectNameLabel:     r.projectName,
 		},
-		Env: []string{
-			"EXT_UID=" + strconv.Itoa(os.Getuid()),
-		},
-		User: "root",
+		// The user inside has uid 1000. This works even on macOS where the default user has uid 501.
+		// See https://stackoverflow.com/questions/43097341/docker-on-macosx-does-not-translate-file-ownership-correctly-in-volumes
+		User: "",
 	}
 
 	err = r.addImageDefinedLabels(image, containerConfig.Labels)
@@ -129,9 +137,12 @@ func (r *runner) runContainer(image string) error {
 		},
 	}
 
+	// macOS does not support host networking.
+	// See https://github.com/docker/for-mac/issues/2716
 	if runtime.GOOS == "darwin" {
+		portSpec := fmt.Sprintf("127.0.0.1:%v:%v/tcp", r.port, "8443")
 		hostConfig.NetworkMode = ""
-		exposed, bindings, err := nat.ParsePortSpecs([]string{fmt.Sprintf("%v:%v/tcp", r.port, r.port)})
+		exposed, bindings, err := nat.ParsePortSpecs([]string{portSpec})
 		if err != nil {
 			return xerrors.Errorf("failed to parse port spec: %w", err)
 		}