Clean up applet initialization (#1036)

* Clean up applet initialization

* Previously you would a `runtime.Applet{}`, optionally set some fields
  on it, and then call its `Load` function. That function would set some
  other fields, and it was all kind of a mess.

  Replace all this with a `runtime.NewApplet()` function that accepts
  various options.

* Get rid of the distinction between "filename" and "ID" for an applet.
  Each applet now only has an ID.

* Replace Starlark thread initializers with explicit options or other
  alternatives. For example, `Run()` now accepts a `context.Context`,
  and there is a `WithPrintFunc` option.

Minor:

* Upgrade to Go 1.22.2.

* Replace deprecated usages of `io/ioutil` and `pkg/errors`.

* Fix lint errors

* Add a function for running Starlark tests

.github/workflows/main.yml

@@ -16,7 +16,7 @@ jobs:
       - name: Set up Go
         uses: actions/setup-go@v4
         with:
-          go-version: "1.21"
+          go-version: "1.22.2"
 
       - name: Install buildifier
         run: make install-buildifier
@@ -36,7 +36,7 @@ jobs:
       - name: Install Go
         uses: actions/setup-go@v4
         with:
-          go-version: "1.21"
+          go-version: "1.22.2"
 
       - name: Install Node
         uses: actions/setup-node@v3
@@ -158,7 +158,7 @@ jobs:
       - name: Install Go
         uses: actions/setup-go@v4
         with:
-          go-version: "1.21"
+          go-version: "1.22.2"
 
       - name: Fetch Release Artifacts
         uses: actions/download-artifact@v3

.github/workflows/pull-request.yml

@@ -14,7 +14,7 @@ jobs:
       - name: Set up Go
         uses: actions/setup-go@v4
         with:
-          go-version: "1.21"
+          go-version: "1.22.2"
 
       - name: Install buildifier
         run: make install-buildifier
@@ -34,7 +34,7 @@ jobs:
       - name: Install Go
         uses: actions/setup-go@v4
         with:
-          go-version: "1.21"
+          go-version: "1.22.2"
 
       - name: Install Node
         uses: actions/setup-node@v3

cmd/community/loadapp.go

@@ -2,11 +2,10 @@ package community
 
 import (
 	"fmt"
-	"io/ioutil"
+	"os"
 	"strings"
 
 	"github.com/spf13/cobra"
-	"go.starlark.net/starlark"
 	"tidbyt.dev/pixlet/runtime"
 )
 
@@ -26,7 +25,7 @@ func LoadApp(cmd *cobra.Command, args []string) error {
 		return fmt.Errorf("script file must have suffix .star: %s", script)
 	}
 
-	src, err := ioutil.ReadFile(script)
+	src, err := os.ReadFile(script)
 	if err != nil {
 		return fmt.Errorf("failed to read file %s: %w", script, err)
 	}
@@ -35,16 +34,7 @@ func LoadApp(cmd *cobra.Command, args []string) error {
 	runtime.InitHTTP(cache)
 	runtime.InitCache(cache)
 
-	// Remove the print function from the starlark thread.
-	initializers := []runtime.ThreadInitializer{}
-	initializers = append(initializers, func(thread *starlark.Thread) *starlark.Thread {
-		thread.Print = func(thread *starlark.Thread, msg string) {}
-		return thread
-	})
-
-	applet := runtime.Applet{}
-	err = applet.LoadWithInitializers("", script, src, nil, initializers...)
-	if err != nil {
+	if _, err := runtime.NewApplet(script, src, runtime.WithPrintDisabled()); err != nil {
 		return fmt.Errorf("failed to load applet: %w", err)
 	}
 

cmd/community/validateicons.go

@@ -46,8 +46,7 @@ func ValidateIcons(cmd *cobra.Command, args []string) error {
 		return thread
 	})
 
-	applet := runtime.Applet{}
-	err = applet.LoadWithInitializers("", args[0], src, nil, initializers...)
+	applet, err := runtime.NewApplet(args[0], src, runtime.WithPrintDisabled())
 	if err != nil {
 		return fmt.Errorf("failed to load applet: %w", err)
 	}
@@ -69,7 +68,7 @@ func ValidateIcons(cmd *cobra.Command, args []string) error {
 		}
 
 		if _, ok := icons.IconsMap[field.Icon]; !ok {
-			return fmt.Errorf("app '%s' contains unknown icon: '%s'", applet.Filename, field.Icon)
+			return fmt.Errorf("app '%s' contains unknown icon: '%s'", applet.ID, field.Icon)
 		}
 	}
 

cmd/profile.go

@@ -2,8 +2,8 @@ package cmd
 
 import (
 	"bytes"
+	"context"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"strings"
 	"time"
@@ -97,7 +97,7 @@ func profile(cmd *cobra.Command, args []string) error {
 }
 
 func ProfileApp(script string, config map[string]string) (*pprof_profile.Profile, error) {
-	src, err := ioutil.ReadFile(script)
+	src, err := os.ReadFile(script)
 	if err != nil {
 		return nil, fmt.Errorf("failed to read file %s: %w", script, err)
 	}
@@ -106,15 +106,7 @@ func ProfileApp(script string, config map[string]string) (*pprof_profile.Profile
 	runtime.InitHTTP(cache)
 	runtime.InitCache(cache)
 
-	// Remove the print function from the starlark thread.
-	initializers := []runtime.ThreadInitializer{}
-	initializers = append(initializers, func(thread *starlark.Thread) *starlark.Thread {
-		thread.Print = func(thread *starlark.Thread, msg string) {}
-		return thread
-	})
-
-	applet := runtime.Applet{}
-	err = applet.LoadWithInitializers("", script, src, nil, initializers...)
+	applet, err := runtime.NewApplet(script, src, runtime.WithPrintDisabled())
 	if err != nil {
 		return nil, fmt.Errorf("failed to load applet: %w", err)
 	}
@@ -124,7 +116,7 @@ func ProfileApp(script string, config map[string]string) (*pprof_profile.Profile
 		return nil, fmt.Errorf("error starting profiler: %w", err)
 	}
 
-	_, err = applet.Run(config, initializers...)
+	_, err = applet.RunWithConfig(context.Background(), config)
 	if err != nil {
 		_ = starlark.StopProfile()
 		return nil, fmt.Errorf("error running script: %w", err)

cmd/render.go

@@ -4,18 +4,15 @@ import (
 	"context"
 	"fmt"
 	"image"
-	"io/ioutil"
 	"os"
 	"strings"
 	"time"
 
 	"github.com/spf13/cobra"
-	"go.starlark.net/starlark"
 
 	"tidbyt.dev/pixlet/encode"
 	"tidbyt.dev/pixlet/globals"
 	"tidbyt.dev/pixlet/runtime"
-	"tidbyt.dev/pixlet/starlarkutil"
 )
 
 var (
@@ -106,45 +103,37 @@ func render(cmd *cobra.Command, args []string) error {
 		config[split[0]] = strings.Join(split[1:], "=")
 	}
 
-	src, err := ioutil.ReadFile(script)
+	src, err := os.ReadFile(script)
 	if err != nil {
 		return fmt.Errorf("failed to read file %s: %w", script, err)
 	}
 
 	// Remove the print function from the starlark thread if the silent flag is
 	// passed.
-	initializers := []runtime.ThreadInitializer{}
+	var opts []runtime.AppletOption
 	if silenceOutput {
-		initializers = append(initializers, func(thread *starlark.Thread) *starlark.Thread {
-			thread.Print = func(thread *starlark.Thread, msg string) {}
-			return thread
-		})
+		opts = append(opts, runtime.WithPrintDisabled())
 	}
 
-	// Timeout?
+	ctx := context.Background()
 	if timeout > 0 {
-		initializers = append(initializers, func(thread *starlark.Thread) *starlark.Thread {
-			ctx, _ := context.WithTimeoutCause(
-				context.Background(),
-				time.Duration(timeout)*time.Millisecond,
-				fmt.Errorf("timeout after %dms", timeout),
-			)
-			starlarkutil.AttachThreadContext(ctx, thread)
-			return thread
-		})
+		ctx, _ = context.WithTimeoutCause(
+			ctx,
+			time.Duration(timeout)*time.Millisecond,
+			fmt.Errorf("timeout after %dms", timeout),
+		)
 	}
 
 	cache := runtime.NewInMemoryCache()
 	runtime.InitHTTP(cache)
 	runtime.InitCache(cache)
 
-	applet := runtime.Applet{}
-	err = applet.LoadWithInitializers("", script, src, nil, initializers...)
+	applet, err := runtime.NewApplet(script, src, opts...)
 	if err != nil {
 		return fmt.Errorf("failed to load applet: %w", err)
 	}
 
-	roots, err := applet.Run(config, initializers...)
+	roots, err := applet.RunWithConfig(ctx, config)
 	if err != nil {
 		return fmt.Errorf("error running script: %w", err)
 	}
@@ -200,7 +189,7 @@ func render(cmd *cobra.Command, args []string) error {
 	if outPath == "-" {
 		_, err = os.Stdout.Write(buf)
 	} else {
-		err = ioutil.WriteFile(outPath, buf, 0644)
+		err = os.WriteFile(outPath, buf, 0644)
 	}
 
 	if err != nil {

docs/gen_widget_imgs.go

@@ -4,9 +4,10 @@ package main
 // documentation.
 
 import (
+	"context"
 	"fmt"
 	"image"
-	"io/ioutil"
+	"os"
 	"strings"
 
 	"tidbyt.dev/pixlet/encode"
@@ -40,7 +41,7 @@ func Magnify(input image.Image) (image.Image, error) {
 }
 
 func main() {
-	files, err := ioutil.ReadDir(".")
+	files, err := os.ReadDir(".")
 	if err != nil {
 		panic(err)
 	}
@@ -51,7 +52,7 @@ func main() {
 			continue
 		}
 
-		content, err := ioutil.ReadFile(f.Name())
+		content, err := os.ReadFile(f.Name())
 		if err != nil {
 			panic(err)
 		}
@@ -67,13 +68,12 @@ def main():
     return render.Root(child=w)
 `, snippet)
 
-		app := runtime.Applet{}
-		err = app.Load(fmt.Sprintf("id-%s", name), name, []byte(src), nil)
+		app, err := runtime.NewApplet(name, []byte(src))
 		if err != nil {
 			panic(err)
 		}
 
-		roots, err := app.Run(nil)
+		roots, err := app.Run(context.Background())
 		if err != nil {
 			panic(err)
 		}
@@ -83,7 +83,7 @@ def main():
 			panic(err)
 		}
 
-		err = ioutil.WriteFile(fmt.Sprintf("img/widget_%s.gif", name), gif, 0644)
+		err = os.WriteFile(fmt.Sprintf("img/widget_%s.gif", name), gif, 0644)
 		if err != nil {
 			panic(err)
 		}

docs/schema/location/example.star

@@ -1,6 +1,6 @@
+load("encoding/json.star", "json")
 load("render.star", "render")
 load("schema.star", "schema")
-load("encoding/json.star", "json")
 
 DEFAULT_LOCATION = """
 {

docs/schema/locationbased/example.star

@@ -1,6 +1,6 @@
+load("encoding/json.star", "json")
 load("render.star", "render")
 load("schema.star", "schema")
-load("encoding/json.star", "json")
 
 EXAMPLE_LOCATION = """
 {

docs/schema/oauth2/example.star

@@ -1,8 +1,8 @@
+load("encoding/json.star", "json")
 load("http.star", "http")
 load("render.star", "render")
 load("schema.star", "schema")
 load("secret.star", "secret")
-load("encoding/json.star", "json")
 
 OAUTH2_CLIENT_SECRET = secret.decrypt("your-client-secret")
 

docs/schema/photoselect/example.star

@@ -1,6 +1,6 @@
+load("encoding/base64.star", "base64")
 load("render.star", "render")
 load("schema.star", "schema")
-load("encoding/base64.star", "base64")
 
 def main(config):
     encoded = config.get("photo", DEFAULT_PHOTO)

encode/encode.go

@@ -2,9 +2,9 @@ package encode
 
 import (
 	"crypto/sha256"
+	"fmt"
 	"image"
 
-	"github.com/pkg/errors"
 	"github.com/vmihailenco/msgpack/v5"
 
 	"tidbyt.dev/pixlet/render"
@@ -77,7 +77,7 @@ func (s *Screens) Hash() ([]byte, error) {
 
 	j, err := msgpack.Marshal(hashable)
 	if err != nil {
-		return nil, errors.Wrap(err, "marshaling render tree to JSON")
+		return nil, fmt.Errorf("marshaling render tree to JSON: %w", err)
 	}
 
 	h := sha256.Sum256(j)

encode/encode_bench_test.go

@@ -1,6 +1,7 @@
 package encode
 
 import (
+	"context"
 	"testing"
 
 	"tidbyt.dev/pixlet/runtime"
@@ -71,15 +72,13 @@ def main(config):
 `
 
 func BenchmarkRunAndRender(b *testing.B) {
-	app := &runtime.Applet{}
-	err := app.Load("benchid", "benchmark.star", []byte(BenchmarkDotStar), nil)
+	app, err := runtime.NewApplet("benchmark.star", []byte(BenchmarkDotStar))
 	if err != nil {
 		b.Error(err)
 	}
 
-	config := map[string]string{}
 	for i := 0; i < b.N; i++ {
-		roots, err := app.Run(config)
+		roots, err := app.Run(context.Background())
 		if err != nil {
 			b.Error(err)
 		}