Add language field to metadata

cli/daemon/apps/apps.go

@@ -351,6 +351,14 @@ func (i *Instance) Experiments(environ []string) (*experiments.Set, error) {
 	return experiments.FromAppFileAndEnviron(exp, environ)
 }
 
+func (i *Instance) Lang() appfile.Lang {
+	appFile, err := appfile.ParseFile(filepath.Join(i.root, appfile.Name))
+	if err != nil {
+		return appfile.LangGo
+	}
+	return appFile.Lang
+}
+
 // GlobalCORS returns the CORS configuration for the app which
 // will be applied against all API gateways into the app
 func (i *Instance) GlobalCORS() (appfile.CORS, error) {

cli/daemon/daemon.go

@@ -102,7 +102,7 @@ func (s *Server) GenClient(ctx context.Context, params *daemonpb.GenClientReques
 		}
 
 		// Parse the app to figure out what infrastructure is needed.
-		bld := builderimpl.Resolve(expSet)
+		bld := builderimpl.Resolve(app.Lang(), expSet)
 		defer fns.CloseIgnore(bld)
 		parse, err := bld.Parse(ctx, builder.ParseParams{
 			Build:       builder.DefaultBuildInfo(),

cli/daemon/db.go

@@ -53,7 +53,7 @@ func (s *Server) dbConnectLocal(ctx context.Context, req *daemonpb.DBConnectRequ
 	}
 
 	// Parse the app to figure out what infrastructure is needed.
-	bld := builderimpl.Resolve(expSet)
+	bld := builderimpl.Resolve(app.Lang(), expSet)
 	defer fns.CloseIgnore(bld)
 	parse, err := bld.Parse(ctx, builder.ParseParams{
 		Build:       builder.DefaultBuildInfo(),
@@ -176,7 +176,7 @@ func (s *Server) DBProxy(params *daemonpb.DBProxyRequest, stream daemonpb.Daemon
 		}
 
 		// Parse the app to figure out what infrastructure is needed.
-		bld := builderimpl.Resolve(expSet)
+		bld := builderimpl.Resolve(app.Lang(), expSet)
 		defer fns.CloseIgnore(bld)
 		parse, err := bld.Parse(ctx, builder.ParseParams{
 			Build:       builder.DefaultBuildInfo(),
@@ -274,7 +274,7 @@ func (s *Server) DBReset(req *daemonpb.DBResetRequest, stream daemonpb.Daemon_DB
 	}
 
 	// Parse the app to figure out what infrastructure is needed.
-	bld := builderimpl.Resolve(expSet)
+	bld := builderimpl.Resolve(app.Lang(), expSet)
 	defer fns.CloseIgnore(bld)
 	parse, err := bld.Parse(stream.Context(), builder.ParseParams{
 		Build:       builder.DefaultBuildInfo(),

cli/daemon/debug.go

@@ -43,7 +43,7 @@ func (s *Server) DumpMeta(ctx context.Context, req *daemonpb.DumpMetaRequest) (*
 		UncommittedChanges: vcsRevision.Uncommitted,
 	}
 
-	bld := builderimpl.Resolve(expSet)
+	bld := builderimpl.Resolve(app.Lang(), expSet)
 	defer fns.CloseIgnore(bld)
 	parse, err := bld.Parse(ctx, builder.ParseParams{
 		Build:       buildInfo,

cli/daemon/export/export.go

@@ -50,7 +50,7 @@ func Docker(ctx context.Context, app *apps.Instance, req *daemonpb.ExportRequest
 		UncommittedChanges: vcsRevision.Uncommitted,
 	}
 
-	bld := builderimpl.Resolve(expSet)
+	bld := builderimpl.Resolve(app.Lang(), expSet)
 	defer fns.CloseIgnore(bld)
 	parse, err := bld.Parse(ctx, builder.ParseParams{
 		Build:       buildInfo,

cli/daemon/run/check.go

@@ -57,7 +57,7 @@ func (mgr *Manager) Check(ctx context.Context, p CheckParams) (buildDir string,
 		UncommittedChanges: vcsRevision.Uncommitted,
 	}
 
-	bld := builderimpl.Resolve(expSet)
+	bld := builderimpl.Resolve(p.App.Lang(), expSet)
 	defer fns.CloseIgnore(bld)
 	parse, err := bld.Parse(ctx, builder.ParseParams{
 		Build:       buildInfo,

cli/daemon/run/exec_script.go

@@ -74,7 +74,7 @@ func (mgr *Manager) ExecScript(ctx context.Context, p ExecScriptParams) (err err
 	parseOp := tracker.Add("Building Encore application graph", start)
 	topoOp := tracker.Add("Analyzing service topology", start)
 
-	bld := builderimpl.Resolve(expSet)
+	bld := builderimpl.Resolve(p.App.Lang(), expSet)
 	defer fns.CloseIgnore(bld)
 	vcsRevision := vcs.GetRevision(p.App.Root())
 	buildInfo := builder.BuildInfo{

cli/daemon/run/run.go

@@ -314,7 +314,7 @@ func (r *Run) buildAndStart(ctx context.Context, tracker *optracker.OpTracker, i
 	}
 
 	if r.Builder == nil {
-		r.Builder = builderimpl.Resolve(expSet)
+		r.Builder = builderimpl.Resolve(r.App.Lang(), expSet)
 	}
 
 	vcsRevision := vcs.GetRevision(r.App.Root())

cli/daemon/run/tests.go

@@ -39,7 +39,7 @@ func (mgr *Manager) Test(ctx context.Context, params TestParams) (err error) {
 	if err != nil {
 		return err
 	}
-	bld := builderimpl.Resolve(expSet)
+	bld := builderimpl.Resolve(params.App.Lang(), expSet)
 	defer fns.CloseIgnore(bld)
 
 	spec, err := mgr.testSpec(ctx, bld, expSet, params.TestSpecParams)
@@ -95,7 +95,7 @@ func (mgr *Manager) TestSpec(ctx context.Context, params TestSpecParams) (*TestS
 	if err != nil {
 		return nil, err
 	}
-	bld := builderimpl.Resolve(expSet)
+	bld := builderimpl.Resolve(params.App.Lang(), expSet)
 	defer fns.CloseIgnore(bld)
 
 	spec, err := mgr.testSpec(ctx, bld, expSet, &params)

cli/daemon/userfacing.go

@@ -46,7 +46,7 @@ func (s *Server) genUserFacing(ctx context.Context, app *apps.Instance) error {
 		UncommittedChanges: vcsRevision.Uncommitted,
 	}
 
-	bld := builderimpl.Resolve(expSet)
+	bld := builderimpl.Resolve(app.Lang(), expSet)
 	defer fns.CloseIgnore(bld)
 
 	parse, err := bld.Parse(ctx, builder.ParseParams{

e2e-tests/app_test.go

@@ -212,7 +212,7 @@ func testBuild(t testing.TB, appRoot string, env []string) (*builder.ParseResult
 		t.Fatal(err)
 	}
 
-	bld := builderimpl.Resolve(expSet)
+	bld := builderimpl.Resolve("", expSet)
 	defer fns.CloseIgnore(bld)
 	ctx := context.Background()
 

pkg/appfile/appfile.go

@@ -19,6 +19,13 @@ import (
 // (which is usually the Git repository root).
 const Name = "encore.app"
 
+type Lang string
+
+const (
+	LangGo Lang = "go"
+	LangTS Lang = "typescript"
+)
+
 // File is a parsed encore.app file.
 type File struct {
 	// ID is the encore.dev app id for the app.
@@ -32,6 +39,10 @@ type File struct {
 	// Do not use these features in production without consulting the Encore team.
 	Experiments []experiments.Name `json:"experiments,omitempty"`
 
+	// Lang is the language the app is written in.
+	// If empty it defaults to Go.
+	Lang Lang `json:"lang"`
+
 	// Configure global CORS settings for the application which
 	// will be applied to all API gateways into the application.
 	GlobalCORS *CORS `json:"global_cors,omitempty"`
@@ -111,6 +122,15 @@ func Parse(data []byte) (*File, error) {
 		return nil, fmt.Errorf("appfile.Parse: %v", err)
 	}
 
+	switch f.Lang {
+	case LangGo, LangTS:
+	// Do nothing
+	case "":
+		f.Lang = LangGo
+	default:
+		return nil, fmt.Errorf("appfile.Parse: invalid lang %q", f.Lang)
+	}
+
 	// Parse deprecated fields into the new Build struct.
 	f.Build.CgoEnabled = f.Build.CgoEnabled || f.CgoEnabled
 	if f.Build.Docker.BaseImage == "" {

pkg/builder/builderimpl/builders.go

@@ -2,13 +2,14 @@ package builderimpl
 
 import (
 	"encore.dev/appruntime/exported/experiments"
+	"encr.dev/pkg/appfile"
 	"encr.dev/pkg/builder"
 	"encr.dev/v2/tsbuilder"
 	"encr.dev/v2/v2builder"
 )
 
-func Resolve(expSet *experiments.Set) builder.Impl {
-	if experiments.TypeScript.Enabled(expSet) {
+func Resolve(lang appfile.Lang, expSet *experiments.Set) builder.Impl {
+	if lang == appfile.LangTS || experiments.TypeScript.Enabled(expSet) {
 		return tsbuilder.New()
 	}
 	return v2builder.BuilderImpl{}