Merge branch 'thallgren/read-only'

Dockerfile

@@ -1,7 +1,7 @@
-FROM --platform=$BUILDPLATFORM golang:alpine as builder
+FROM --platform=$BUILDPLATFORM golang:alpine AS builder
 
 RUN apk add --no-cache --virtual .build-deps gcc libc-dev
-WORKDIR docker-volume-telemount
+WORKDIR /docker-volume-telemount
 COPY . .
 ARG TARGETOS
 ARG TARGETARCH

pkg/sftp/driver.go

@@ -54,6 +54,7 @@ func (d *driver) Create(r *volume.CreateRequest) (err error) {
 
 	var container, dir, host string
 	var port uint16
+	var readOnly bool
 	for key, val := range r.Options {
 		switch key {
 		case "container":
@@ -68,6 +69,11 @@ func (d *driver) Create(r *volume.CreateRequest) (err error) {
 			} else {
 				port = uint16(pv)
 			}
+		case "ro":
+			readOnly, err = strconv.ParseBool(val)
+			if err != nil {
+				return fmt.Errorf("ro must be a boolean")
+			}
 		default:
 			return fmt.Errorf("illegal option %q", key)
 		}
@@ -88,7 +94,7 @@ func (d *driver) Create(r *volume.CreateRequest) (err error) {
 	}
 	d.lock.Lock()
 	defer d.lock.Unlock()
-	m, err := d.getRemoteMount(host, port)
+	m, err := d.getRemoteMount(host, port, readOnly)
 	if err != nil {
 		return err
 	}
@@ -232,13 +238,20 @@ func (d *driver) Capabilities() *volume.CapabilitiesResponse {
 	return &volume.CapabilitiesResponse{Capabilities: volume.Capability{Scope: "local"}}
 }
 
-func (d *driver) getRemoteMount(host string, port uint16) (*mount, error) {
+func (d *driver) getRemoteMount(host string, port uint16, readOnly bool) (*mount, error) {
 	ps := strconv.Itoa(int(port))
 	key := net.JoinHostPort(host, ps)
 	if m, ok := d.remoteMounts[key]; ok {
-		return m, nil
+		if m.readOnly == readOnly {
+			return m, nil
+		}
+		if m.readOnly {
+			return nil, fmt.Errorf("writable access requested for read-only %s", key)
+		}
+		// Can't let a writable volume pose as read-only
+		return nil, fmt.Errorf("read-only access requested writeable %s", key)
 	}
-	m := newMount(filepath.Join(d.volumePath, host, ps), host, port, func() {
+	m := newMount(filepath.Join(d.volumePath, host, ps), host, port, readOnly, func() {
 		d.lock.Lock()
 		delete(d.remoteMounts, key)
 		d.lock.Unlock()

pkg/sftp/mount.go

@@ -23,24 +23,26 @@ type mount struct {
 	mountPoint string
 	host       string
 	port       uint16
+	readOnly   bool
 	mounted    atomic.Bool
 	done       chan error
 	volumes    map[string]*volumeDir
 	proc       *os.Process
 }
 
-func newMount(mountPoint, host string, port uint16, cancel context.CancelFunc) *mount {
+func newMount(mountPoint, host string, port uint16, readOnly bool, cancel context.CancelFunc) *mount {
 	return &mount{
 		mountPoint: mountPoint,
 		host:       host,
 		port:       port,
+		readOnly:   readOnly,
 		volumes:    make(map[string]*volumeDir),
 		cancel:     cancel,
 	}
 }
 
 func (m *mount) String() string {
-	return fmt.Sprintf("port=%d, mountPoint=%s", m.port, m.mountPoint)
+	return fmt.Sprintf("port=%d, mountPoint=%s, readOnly=%t", m.port, m.mountPoint, m.readOnly)
 }
 
 func (m *mount) addVolume(name, dir string) {
@@ -102,6 +104,9 @@ func (m *mount) mountVolume() error {
 		"-o", "auto_unmount",
 		"-o", "allow_root", // needed to make --docker-run work as docker runs as root
 	}
+	if m.readOnly {
+		sshfsArgs = append(sshfsArgs, "-o", "ro")
+	}
 
 	var sl io.Writer
 	if log.IsDebug() {