werkdock: ordered mounts with --tmpfs, images verb, :rw accepted

Session C groundwork: Werkator's git-metadata mask needs a tmpfs BETWEEN binds (ro-bind .git, tmpfs .git/werkator, bind workspace), so -v and --tmpfs now collect into one ordered mount list and RunSpec carries Mounts instead of Binds. --tmpfs DEST is the docker flag of the same name. `werkdock images` lists loaded image names one per line, so a consumer can check existence through the CLI. -v accepts the explicit :rw docker default instead of refusing it. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
2026-09-01 15:39:31 +02:00
parent 263245d49e
commit a2da6454f7
9 changed files with 236 additions and 66 deletions
@@ -27,6 +27,8 @@ func Main(args []string) int {
 		return runCmd(args[1:])
 	case "load":
 		return loadCmd(args[1:])
+	case "images":
+		return imagesCmd(args[1:])
 	case "doctor":
 		return doctorCmd(args[1:])
 	case "version", "--version":
@@ -49,11 +51,13 @@ Network, uid, /proc, /dev, and /tmp come from the host by contract.
 Usage:
  werkdock run [flags] IMAGE COMMAND [ARG...]   run a command in a sandbox
  werkdock load -i ARCHIVE [--name NAME]        import a rootfs archive as an image
+  werkdock images                               list loaded images, one name per line
  werkdock doctor [TARGET_DIR]                  check whether this host can run sandboxes
  werkdock version                              print the version

 Run flags:
-  -v, --volume SRC:DEST[:ro]   bind mount (repeatable, applied in order)
+  -v, --volume SRC:DEST[:ro]   bind mount (repeatable; -v and --tmpfs apply in flag order)
+      --tmpfs DEST             empty tmpfs at DEST (repeatable)
  -e, --env KEY=VALUE          set an environment variable (KEY alone copies it from the host)
  -w, --workdir DIR            working directory inside the sandbox (default /)
      --rm                     remove the instance afterwards (currently required)
@@ -0,0 +1,35 @@
+package cli
+
+import (
+	"flag"
+	"fmt"
+	"io"
+
+	"werkdock/internal/store"
+)
+
+// imagesCmd prints the loaded image names, one per line — machine-usable
+// (Werkator checks image existence through it) and close enough to
+// `docker images --format '{{.Repository}}'`.
+func imagesCmd(args []string) int {
+	fs := flag.NewFlagSet("images", flag.ContinueOnError)
+	fs.SetOutput(io.Discard)
+	if err := fs.Parse(args); err != nil {
+		return fail(err)
+	}
+	if len(fs.Args()) != 0 {
+		return fail(fmt.Errorf("unexpected argument %q", fs.Args()[0]))
+	}
+	st, err := store.Default()
+	if err != nil {
+		return fail(err)
+	}
+	names, err := st.List()
+	if err != nil {
+		return fail(err)
+	}
+	for _, name := range names {
+		fmt.Println(name)
+	}
+	return 0
+}
@@ -16,7 +16,7 @@ import (
 // runOptions is the parsed form of `werkdock run` flags, separated from
 // execution so the parsing is testable and a later daemon can reuse it.
 type runOptions struct {
-	Volumes []engine.Bind
+	Mounts  []engine.Mount
 	Env     []engine.EnvVar
 	Workdir string
 	Remove  bool
@@ -39,7 +39,7 @@ func runCmd(args []string) int {
 	}
 	spec := engine.RunSpec{
 		RootFS:  rootfs,
-		Binds:   hostBinds(opts.Volumes),
+		Mounts:  hostMounts(opts.Mounts),
 		Env:     opts.Env,
 		Workdir: opts.Workdir,
 		Command: opts.Command,
@@ -52,15 +52,15 @@ func runCmd(args []string) int {
 	return code
 }

-// hostBinds prepends the host mounts the contract prescribes: DNS comes
+// hostMounts prepends the host mounts the contract prescribes: DNS comes
 // from the host, so /etc/resolv.conf is bound read-only when it exists —
-// before the user binds, so an explicit bind over /etc wins.
-func hostBinds(volumes []engine.Bind) []engine.Bind {
-	var binds []engine.Bind
+// before the user mounts, so an explicit mount over /etc wins.
+func hostMounts(mounts []engine.Mount) []engine.Mount {
+	var all []engine.Mount
 	if fi, err := os.Stat("/etc/resolv.conf"); err == nil && fi.Mode().IsRegular() {
-		binds = append(binds, engine.Bind{Source: "/etc/resolv.conf", Dest: "/etc/resolv.conf", ReadOnly: true})
+		all = append(all, engine.Mount{Mode: engine.MountRoBind, Source: "/etc/resolv.conf", Dest: "/etc/resolv.conf"})
 	}
-	return append(binds, volumes...)
+	return append(all, mounts...)
 }

 // parseRun parses the docker-shaped run flags. Docker flags whose
@@ -69,10 +69,16 @@ func hostBinds(volumes []engine.Bind) []engine.Bind {
 func parseRun(args []string, getenv func(string) string) (*runOptions, error) {
 	fs := flag.NewFlagSet("run", flag.ContinueOnError)
 	fs.SetOutput(io.Discard)
-	var volumes, envs stringList
+	var envs stringList
 	opts := &runOptions{}
-	fs.Var(&volumes, "v", "bind mount SRC:DEST[:ro]")
-	fs.Var(&volumes, "volume", "bind mount SRC:DEST[:ro]")
+	// -v and --tmpfs collect into ONE ordered list: bwrap layers mounts in
+	// order, so a tmpfs between two binds (the git-metadata mask) must stay
+	// between them.
+	volumes := &mountFlag{mounts: &opts.Mounts}
+	tmpfs := &mountFlag{mounts: &opts.Mounts, tmpfs: true}
+	fs.Var(volumes, "v", "bind mount SRC:DEST[:ro]")
+	fs.Var(volumes, "volume", "bind mount SRC:DEST[:ro]")
+	fs.Var(tmpfs, "tmpfs", "empty tmpfs at DEST")
 	fs.Var(&envs, "e", "environment variable KEY=VALUE")
 	fs.Var(&envs, "env", "environment variable KEY=VALUE")
 	fs.StringVar(&opts.Workdir, "w", "", "working directory inside the sandbox")
@@ -101,13 +107,6 @@ func parseRun(args []string, getenv func(string) string) (*runOptions, error) {
 	}
 	opts.Image = rest[0]
 	opts.Command = rest[1:]
-	for _, v := range volumes {
-		bind, err := parseVolume(v)
-		if err != nil {
-			return nil, err
-		}
-		opts.Volumes = append(opts.Volumes, bind)
-	}
 	for _, e := range envs {
 		opts.Env = append(opts.Env, parseEnv(e, getenv))
 	}
@@ -117,25 +116,54 @@ func parseRun(args []string, getenv func(string) string) (*runOptions, error) {
 	return opts, nil
 }

-func parseVolume(v string) (engine.Bind, error) {
+func parseVolume(v string) (engine.Mount, error) {
 	parts := strings.Split(v, ":")
 	if len(parts) < 2 || len(parts) > 3 {
-		return engine.Bind{}, fmt.Errorf("invalid volume %q, expected SRC:DEST[:ro]", v)
+		return engine.Mount{}, fmt.Errorf("invalid volume %q, expected SRC:DEST[:ro]", v)
 	}
-	bind := engine.Bind{Source: parts[0], Dest: parts[1]}
+	mount := engine.Mount{Mode: engine.MountBind, Source: parts[0], Dest: parts[1]}
 	if len(parts) == 3 {
-		if parts[2] != "ro" {
-			return engine.Bind{}, fmt.Errorf("invalid volume option %q in %q, only 'ro' is supported", parts[2], v)
+		switch parts[2] {
+		case "ro":
+			mount.Mode = engine.MountRoBind
+		case "rw":
+			// docker accepts :rw as the explicit default; so do we
+		default:
+			return engine.Mount{}, fmt.Errorf("invalid volume option %q in %q, only 'ro' and 'rw' are supported", parts[2], v)
 		}
-		bind.ReadOnly = true
 	}
-	if !filepath.IsAbs(bind.Source) {
-		return engine.Bind{}, fmt.Errorf("volume source must be an absolute path: %s", bind.Source)
+	if !filepath.IsAbs(mount.Source) {
+		return engine.Mount{}, fmt.Errorf("volume source must be an absolute path: %s", mount.Source)
 	}
-	if !filepath.IsAbs(bind.Dest) {
-		return engine.Bind{}, fmt.Errorf("volume destination must be an absolute path: %s", bind.Dest)
+	if !filepath.IsAbs(mount.Dest) {
+		return engine.Mount{}, fmt.Errorf("volume destination must be an absolute path: %s", mount.Dest)
 	}
-	return bind, nil
+	return mount, nil
+}
+
+// mountFlag appends -v/--volume and --tmpfs values to one shared,
+// ordered mount list.
+type mountFlag struct {
+	mounts *[]engine.Mount
+	tmpfs  bool
+}
+
+func (f *mountFlag) String() string { return "" }
+
+func (f *mountFlag) Set(v string) error {
+	if f.tmpfs {
+		if !filepath.IsAbs(v) {
+			return fmt.Errorf("tmpfs destination must be an absolute path: %s", v)
+		}
+		*f.mounts = append(*f.mounts, engine.Mount{Mode: engine.MountTmpfs, Dest: v})
+		return nil
+	}
+	mount, err := parseVolume(v)
+	if err != nil {
+		return err
+	}
+	*f.mounts = append(*f.mounts, mount)
+	return nil
 }

 func parseEnv(e string, getenv func(string) string) engine.EnvVar {
@@ -28,12 +28,12 @@ func TestParseRunSupportedFlags(t *testing.T) {
 	if !reflect.DeepEqual(opts.Command, []string{"sh", "-c", "./gradlew build"}) {
 		t.Errorf("command: got %q", opts.Command)
 	}
-	wantVolumes := []engine.Bind{
-		{Source: "/repo", Dest: "/repo"},
-		{Source: "/cache", Dest: "/root/.gradle", ReadOnly: true},
+	wantMounts := []engine.Mount{
+		{Mode: engine.MountBind, Source: "/repo", Dest: "/repo"},
+		{Mode: engine.MountRoBind, Source: "/cache", Dest: "/root/.gradle"},
 	}
-	if !reflect.DeepEqual(opts.Volumes, wantVolumes) {
-		t.Errorf("volumes: got %+v", opts.Volumes)
+	if !reflect.DeepEqual(opts.Mounts, wantMounts) {
+		t.Errorf("mounts: got %+v", opts.Mounts)
 	}
 	if !reflect.DeepEqual(opts.Env, []engine.EnvVar{{Key: "CI", Value: "true"}}) {
 		t.Errorf("env: got %+v", opts.Env)
@@ -96,7 +96,8 @@ func TestParseRunValidation(t *testing.T) {
 		{"no image", []string{"--rm"}, "no image specified"},
 		{"no command", []string{"--rm", "img"}, "no command specified"},
 		{"volume without dest", []string{"--rm", "-v", "/only-src", "img", "true"}, "expected SRC:DEST"},
-		{"volume with bad option", []string{"--rm", "-v", "/a:/b:rw", "img", "true"}, "only 'ro' is supported"},
+		{"volume with bad option", []string{"--rm", "-v", "/a:/b:cached", "img", "true"}, "only 'ro' and 'rw' are supported"},
+		{"relative tmpfs dest", []string{"--rm", "--tmpfs", "rel", "img", "true"}, "absolute"},
 		{"relative volume source", []string{"--rm", "-v", "rel:/b", "img", "true"}, "absolute"},
 		{"relative volume dest", []string{"--rm", "-v", "/a:rel", "img", "true"}, "absolute"},
 		{"relative workdir", []string{"--rm", "-w", "rel", "img", "true"}, "absolute"},
@@ -111,6 +112,39 @@ func TestParseRunValidation(t *testing.T) {
 	}
 }

+func TestParseRunKeepsMountFlagOrderAcrossVolumeAndTmpfs(t *testing.T) {
+	// The git-metadata mask depends on it: ro-bind .git, tmpfs over
+	// .git/werkator, then the workspace bind — in exactly this order.
+	opts, err := parseRun([]string{
+		"--rm",
+		"-v", "/r/.git:/r/.git:ro",
+		"--tmpfs", "/r/.git/werkator",
+		"-v", "/r/ws:/r/ws",
+		"img", "true",
+	}, noEnv)
+	if err != nil {
+		t.Fatal(err)
+	}
+	want := []engine.Mount{
+		{Mode: engine.MountRoBind, Source: "/r/.git", Dest: "/r/.git"},
+		{Mode: engine.MountTmpfs, Dest: "/r/.git/werkator"},
+		{Mode: engine.MountBind, Source: "/r/ws", Dest: "/r/ws"},
+	}
+	if !reflect.DeepEqual(opts.Mounts, want) {
+		t.Errorf("mounts: got %+v", opts.Mounts)
+	}
+}
+
+func TestParseRunAcceptsTheExplicitRwVolumeOption(t *testing.T) {
+	opts, err := parseRun([]string{"--rm", "-v", "/a:/b:rw", "img", "true"}, noEnv)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !reflect.DeepEqual(opts.Mounts, []engine.Mount{{Mode: engine.MountBind, Source: "/a", Dest: "/b"}}) {
+		t.Errorf("mounts: got %+v", opts.Mounts)
+	}
+}
+
 func TestParseRunStopsFlagParsingAtTheImage(t *testing.T) {
 	// Docker semantics: everything after the image belongs to the
 	// command, even if it looks like a flag.