universe vendoring

Rather than injecting universe at runtime, this change will vendor
alpha.dagger.io in `cue.mod` directly.

Fixes #700

Signed-off-by: Andrea Luzzardi <aluzzardi@gmail.com>

state/state.go

@@ -1,5 +1,10 @@
 package state
 
+import (
+	"context"
+	"path"
+)
+
 // Contents of an environment serialized to a file
 type State struct {
 	// State path
@@ -28,11 +33,26 @@ func (s *State) Source() Input {
 	w := s.Workspace
 	// FIXME: backward compatibility
 	if mod := s.Plan.Module; mod != "" {
-		w = mod
+		w = path.Join(w, mod)
 	}
 	return DirInput(w, []string{}, []string{})
 }
 
+// VendorUniverse vendors the latest (built-in) version of the universe into the
+// environment's `cue.mod`.
+// FIXME: This has nothing to do in `State` and should be tied to a `Workspace`.
+// However, since environments could point to different modules before, we have
+// to handle vendoring on a per environment basis.
+func (s *State) VendorUniverse(ctx context.Context) error {
+	w := s.Workspace
+	// FIXME: backward compatibility
+	if mod := s.Plan.Module; mod != "" {
+		w = path.Join(w, mod)
+	}
+
+	return vendorUniverse(ctx, w)
+}
+
 type Plan struct {
 	Module  string `yaml:"module,omitempty"`
 	Package string `yaml:"package,omitempty"`

state/workspace.go

@@ -12,6 +12,7 @@ import (
 
 	"github.com/rs/zerolog/log"
 	"go.dagger.io/dagger/keychain"
+	"go.dagger.io/dagger/stdlib"
 	"gopkg.in/yaml.v3"
 )
 
@@ -51,6 +52,11 @@ func Init(ctx context.Context, dir string) (*Workspace, error) {
 	if err := os.Mkdir(path.Join(daggerRoot, envDir), 0755); err != nil {
 		return nil, err
 	}
+
+	if err := vendorUniverse(ctx, root); err != nil {
+		return nil, err
+	}
+
 	return &Workspace{
 		Path: root,
 	}, nil
@@ -335,3 +341,63 @@ func (w *Workspace) cleanPackageName(ctx context.Context, pkg string) (string, e
 
 	return p, nil
 }
+
+func cueModInit(ctx context.Context, p string) error {
+	lg := log.Ctx(ctx)
+
+	mod := path.Join(p, "cue.mod")
+	if err := os.Mkdir(mod, 0755); err != nil {
+		if !errors.Is(err, os.ErrExist) {
+			return err
+		}
+	}
+
+	modFile := path.Join(mod, "module.cue")
+	if _, err := os.Stat(modFile); err != nil {
+		if !errors.Is(err, os.ErrNotExist) {
+			return err
+		}
+
+		lg.Debug().Str("mod", p).Msg("initializing cue.mod")
+
+		if err := os.WriteFile(modFile, []byte("module: \"\"\n"), 0600); err != nil {
+			return err
+		}
+	}
+
+	if err := os.Mkdir(path.Join(mod, "usr"), 0755); err != nil {
+		if !errors.Is(err, os.ErrExist) {
+			return err
+		}
+	}
+	if err := os.Mkdir(path.Join(mod, "pkg"), 0755); err != nil {
+		if !errors.Is(err, os.ErrExist) {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func vendorUniverse(ctx context.Context, p string) error {
+	// ensure cue module is initialized
+	if err := cueModInit(ctx, p); err != nil {
+		return err
+	}
+
+	// add universe to `.gitignore`
+	if err := os.WriteFile(
+		path.Join(p, "cue.mod", "pkg", ".gitignore"),
+		[]byte(fmt.Sprintf("# dagger universe\n%s\n", stdlib.PackageName)),
+		0600,
+	); err != nil {
+		return err
+	}
+
+	log.Ctx(ctx).Debug().Str("mod", p).Msg("vendoring universe")
+	if err := stdlib.Vendor(ctx, p); err != nil {
+		return err
+	}
+
+	return nil
+}