Add FxNode render graph playground

Add persistent render graph loadouts, grouped node authoring, code-appending apply behavior, explicit playground lighting, and resilient worker startup.

Amp-Thread-ID: https://ampcode.com/threads/T-01a033d4-0e44-708e-af0e-6166283416ff
Co-authored-by: Heaust Azure <heaust.azure@gmail.com>

server/database.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"crypto/rand"
 	"database/sql"
+	"encoding/json"
 	"errors"
 	"fmt"
 	"math/big"
@@ -17,18 +18,20 @@ import (
 )
 
 const (
-	maximumCodeBytes  = 200 * 1024
-	maximumTitleRunes = 80
+	maximumCodeBytes     = 200 * 1024
+	maximumLoadoutsBytes = 512 * 1024
+	maximumTitleRunes    = 80
 )
 
 var playgroundIDPattern = regexp.MustCompile(`^[a-z0-9]{6,24}$`)
 
 type playground struct {
-	ID        string    `json:"id"`
-	Revision  int       `json:"revision"`
-	Title     string    `json:"title"`
-	Code      string    `json:"code"`
-	CreatedAt time.Time `json:"createdAt"`
+	ID        string          `json:"id"`
+	Revision  int             `json:"revision"`
+	Title     string          `json:"title"`
+	Code      string          `json:"code"`
+	Loadouts  json.RawMessage `json:"loadouts"`
+	CreatedAt time.Time       `json:"createdAt"`
 }
 
 type playgroundStore struct {
@@ -61,16 +64,45 @@ func (store *playgroundStore) initialize() error {
 			revision INTEGER NOT NULL CHECK (revision > 0),
 			title TEXT NOT NULL,
 			code TEXT NOT NULL,
+			loadouts TEXT NOT NULL DEFAULT '[]',
 			created_at TEXT NOT NULL,
 			PRIMARY KEY (id, revision)
 		);
 		CREATE INDEX IF NOT EXISTS playgrounds_created_at
 			ON playgrounds (created_at DESC);
 	`)
+	if err != nil {
+		return err
+	}
+	rows, err := store.Query(`PRAGMA table_info(playgrounds)`)
+	if err != nil {
+		return err
+	}
+	hasLoadouts := false
+	for rows.Next() {
+		var position, notNull, primaryKey int
+		var name, kind string
+		var defaultValue any
+		if err := rows.Scan(&position, &name, &kind, &notNull, &defaultValue, &primaryKey); err != nil {
+			rows.Close()
+			return err
+		}
+		hasLoadouts = hasLoadouts || name == "loadouts"
+	}
+	if err := rows.Err(); err != nil {
+		rows.Close()
+		return err
+	}
+	if err := rows.Close(); err != nil {
+		return err
+	}
+	if !hasLoadouts {
+		_, err = store.Exec(`ALTER TABLE playgrounds ADD COLUMN loadouts TEXT NOT NULL DEFAULT '[]'`)
+	}
 	return err
 }
 
-func (store *playgroundStore) save(ctx context.Context, id, title, code string) (playground, error) {
+func (store *playgroundStore) save(ctx context.Context, id, title, code, loadouts string) (playground, error) {
 	if id != "" && !playgroundIDPattern.MatchString(id) {
 		return playground{}, errors.New("invalid playground id")
 	}
@@ -80,6 +112,16 @@ func (store *playgroundStore) save(ctx context.Context, id, title, code string)
 	if code == "" || len(code) > maximumCodeBytes || !utf8.ValidString(code) {
 		return playground{}, fmt.Errorf("code must contain 1 to %d bytes of UTF-8", maximumCodeBytes)
 	}
+	if loadouts == "" {
+		loadouts = "[]"
+	}
+	if len(loadouts) > maximumLoadoutsBytes || !utf8.ValidString(loadouts) {
+		return playground{}, fmt.Errorf("loadouts must contain at most %d bytes of UTF-8", maximumLoadoutsBytes)
+	}
+	var loadoutList []json.RawMessage
+	if err := json.Unmarshal([]byte(loadouts), &loadoutList); err != nil || loadoutList == nil {
+		return playground{}, errors.New("loadouts must be a JSON array")
+	}
 	if id == "" {
 		var err error
 		id, err = randomPlaygroundID()
@@ -105,11 +147,12 @@ func (store *playgroundStore) save(ctx context.Context, id, title, code string)
 	createdAt := time.Now().UTC().Truncate(time.Millisecond)
 	if _, err := transaction.ExecContext(
 		ctx,
-		`INSERT INTO playgrounds (id, revision, title, code, created_at) VALUES (?, ?, ?, ?, ?)`,
+		`INSERT INTO playgrounds (id, revision, title, code, loadouts, created_at) VALUES (?, ?, ?, ?, ?, ?)`,
 		id,
 		revision,
 		title,
 		code,
+		loadouts,
 		createdAt.Format(time.RFC3339Nano),
 	); err != nil {
 		return playground{}, err
@@ -117,7 +160,10 @@ func (store *playgroundStore) save(ctx context.Context, id, title, code string)
 	if err := transaction.Commit(); err != nil {
 		return playground{}, err
 	}
-	return playground{ID: id, Revision: revision, Title: title, Code: code, CreatedAt: createdAt}, nil
+	return playground{
+		ID: id, Revision: revision, Title: title, Code: code,
+		Loadouts: json.RawMessage(loadouts), CreatedAt: createdAt,
+	}, nil
 }
 
 func (store *playgroundStore) get(ctx context.Context, id string, revision int) (playground, error) {
@@ -125,16 +171,17 @@ func (store *playgroundStore) get(ctx context.Context, id string, revision int)
 		return playground{}, sql.ErrNoRows
 	}
 	var result playground
-	var createdAt string
+	var createdAt, loadouts string
 	err := store.QueryRowContext(
 		ctx,
-		`SELECT id, revision, title, code, created_at FROM playgrounds WHERE id = ? AND revision = ?`,
+		`SELECT id, revision, title, code, loadouts, created_at FROM playgrounds WHERE id = ? AND revision = ?`,
 		id,
 		revision,
-	).Scan(&result.ID, &result.Revision, &result.Title, &result.Code, &createdAt)
+	).Scan(&result.ID, &result.Revision, &result.Title, &result.Code, &loadouts, &createdAt)
 	if err != nil {
 		return playground{}, err
 	}
+	result.Loadouts = json.RawMessage(loadouts)
 	result.CreatedAt, err = time.Parse(time.RFC3339Nano, createdAt)
 	return result, err
 }