feat(scripts): support external file embedding

Reviewed-on: #8

cmd/relspec/assets.go

@@ -0,0 +1,214 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"path/filepath"
+
+	"github.com/spf13/cobra"
+
+	"git.warky.dev/wdevs/relspecgo/pkg/assetloader"
+	"git.warky.dev/wdevs/relspecgo/pkg/pgsql"
+)
+
+var (
+	assetsDir          string
+	assetsConn         string
+	assetsIgnoreErrors bool
+)
+
+var assetsCmd = &cobra.Command{
+	Use:   "assets",
+	Short: "Load and execute asset manifests against a database",
+	Long: `Load local binary and text asset files into a PostgreSQL database.
+
+Assets are described by YAML manifests (assets.yaml) colocated with the files.
+Each manifest entry specifies the file to load and the SQL call to execute.
+File bytes are bound as native pgx parameters — never as SQL text literals —
+so binary files stay byte-exact with no size or encoding limitations.
+
+Manifests must live in directories that follow the naming pattern used by
+relspec scripts:
+  {priority}_{sequence}_{name}/   or   {priority}-{sequence}-{name}/
+
+This allows asset-loading steps to be ordered correctly alongside SQL scripts
+in a migrate-apply pipeline.
+
+Manifest format (assets.yaml):
+  - file: invoice.md
+    call: |
+      INSERT INTO org.filepointer (rid_owner, filename, contenttype, jsonstore)
+      VALUES (1, :filename, 'text/markdown', jsonb_build_object('content', :bytes::text))
+  - file: logo.png
+    call: UPDATE branding SET logo = :bytes WHERE id = 1
+    params:
+      owner_id: "42"
+
+Built-in placeholders:
+  :bytes    — the file's raw content as bytea
+  :filename — the base name of the file (string)
+  :any_key  — a static value declared in the entry's params map`,
+}
+
+var assetsListCmd = &cobra.Command{
+	Use:   "list",
+	Short: "List asset manifests from a directory",
+	Long: `List all asset manifest entries from a directory in execution order.
+
+The directory is scanned recursively for assets.yaml files located in
+directories that follow the {priority}_{sequence}_{name} naming convention.
+
+Example:
+  relspec assets list --dir ./sql`,
+	RunE: runAssetsList,
+}
+
+var assetsExecuteCmd = &cobra.Command{
+	Use:   "execute",
+	Short: "Execute asset manifests against a database",
+	Long: `Execute asset manifest entries from a directory against a PostgreSQL database.
+
+Asset manifests are executed in order: Priority (ascending), Sequence (ascending),
+Directory name (alphabetical). By default, execution stops on the first error.
+Use --ignore-errors to continue even when individual entries fail.
+
+PostgreSQL Connection String Examples:
+  postgres://username:password@localhost:5432/database_name
+  postgresql://user:pass@host/dbname?sslmode=disable
+
+Examples:
+  relspec assets execute --dir ./sql \
+                         --conn "postgres://user:pass@localhost:5432/mydb"
+
+  relspec assets execute --dir ./sql \
+                         --conn "postgres://localhost/mydb" \
+                         --ignore-errors`,
+	RunE: runAssetsExecute,
+}
+
+func init() {
+	assetsListCmd.Flags().StringVar(&assetsDir, "dir", "", "Directory to scan for asset manifests (required)")
+	if err := assetsListCmd.MarkFlagRequired("dir"); err != nil {
+		fmt.Fprintf(os.Stderr, "Error marking dir flag as required: %v\n", err)
+	}
+
+	assetsExecuteCmd.Flags().StringVar(&assetsDir, "dir", "", "Directory to scan for asset manifests (required)")
+	assetsExecuteCmd.Flags().StringVar(&assetsConn, "conn", "", "PostgreSQL connection string (required)")
+	assetsExecuteCmd.Flags().BoolVar(&assetsIgnoreErrors, "ignore-errors", false, "Continue executing even if entries fail")
+	if err := assetsExecuteCmd.MarkFlagRequired("dir"); err != nil {
+		fmt.Fprintf(os.Stderr, "Error marking dir flag as required: %v\n", err)
+	}
+	if err := assetsExecuteCmd.MarkFlagRequired("conn"); err != nil {
+		fmt.Fprintf(os.Stderr, "Error marking conn flag as required: %v\n", err)
+	}
+
+	assetsCmd.AddCommand(assetsListCmd)
+	assetsCmd.AddCommand(assetsExecuteCmd)
+}
+
+func runAssetsList(cmd *cobra.Command, args []string) error {
+	fmt.Fprintf(os.Stderr, "\n=== Asset Manifests List ===\n")
+	fmt.Fprintf(os.Stderr, "Directory: %s\n\n", assetsDir)
+
+	items, err := assetloader.ScanDir(assetsDir)
+	if err != nil {
+		return fmt.Errorf("scanning directory: %w", err)
+	}
+
+	if len(items) == 0 {
+		fmt.Fprintf(os.Stderr, "No asset manifests found.\n\n")
+		return nil
+	}
+
+	fmt.Fprintf(os.Stderr, "Found %d asset entry(ies) in execution order:\n\n", len(items))
+	fmt.Fprintf(os.Stderr, "%-4s %-10s %-8s %-20s %s\n", "No.", "Priority", "Sequence", "Dir", "File")
+	fmt.Fprintf(os.Stderr, "%-4s %-10s %-8s %-20s %s\n", "----", "--------", "--------", "--------------------", "----")
+
+	for i, item := range items {
+		fmt.Fprintf(os.Stderr, "%-4d %-10d %-8d %-20s %s\n",
+			i+1,
+			item.Priority,
+			item.Sequence,
+			item.DirName,
+			filepath.Base(item.Entry.File),
+		)
+	}
+
+	fmt.Fprintf(os.Stderr, "\n")
+	return nil
+}
+
+func runAssetsExecute(cmd *cobra.Command, args []string) error {
+	fmt.Fprintf(os.Stderr, "\n=== Asset Manifests Execution ===\n")
+	fmt.Fprintf(os.Stderr, "Started at: %s\n", getCurrentTimestamp())
+	fmt.Fprintf(os.Stderr, "Directory: %s\n", assetsDir)
+	fmt.Fprintf(os.Stderr, "Database:  %s\n\n", maskPassword(assetsConn))
+
+	fmt.Fprintf(os.Stderr, "[1/2] Scanning asset manifests...\n")
+
+	items, err := assetloader.ScanDir(assetsDir)
+	if err != nil {
+		return fmt.Errorf("scanning directory: %w", err)
+	}
+
+	if len(items) == 0 {
+		fmt.Fprintf(os.Stderr, "      No asset manifests found. Nothing to execute.\n\n")
+		return nil
+	}
+
+	fmt.Fprintf(os.Stderr, "      ✓ Found %d asset entry(ies)\n\n", len(items))
+
+	fmt.Fprintf(os.Stderr, "[2/2] Executing assets in order (Priority → Sequence → Dir)...\n\n")
+
+	ctx := context.Background()
+	conn, err := pgsql.Connect(ctx, assetsConn, "assets-execute")
+	if err != nil {
+		return fmt.Errorf("connecting to database: %w", err)
+	}
+	defer conn.Close(ctx)
+
+	successCount := 0
+	var failures []struct {
+		item assetloader.Item
+		err  error
+	}
+
+	for _, item := range items {
+		name := filepath.Base(item.Entry.File)
+		fmt.Printf("Executing asset: %s (Priority=%d, Sequence=%d, Dir=%s)\n",
+			name, item.Priority, item.Sequence, item.DirName)
+
+		if err := assetloader.ExecuteItem(ctx, conn, item); err != nil {
+			if assetsIgnoreErrors {
+				fmt.Printf("⚠ Error loading %s: %v (continuing due to --ignore-errors)\n", name, err)
+				failures = append(failures, struct {
+					item assetloader.Item
+					err  error
+				}{item, err})
+				continue
+			}
+			return fmt.Errorf("asset %s (Priority=%d, Sequence=%d): %w",
+				name, item.Priority, item.Sequence, err)
+		}
+
+		successCount++
+		fmt.Printf("✓ Successfully loaded: %s\n", name)
+	}
+
+	fmt.Fprintf(os.Stderr, "\n=== Execution Complete ===\n")
+	fmt.Fprintf(os.Stderr, "Completed at: %s\n", getCurrentTimestamp())
+	fmt.Fprintf(os.Stderr, "Total entries: %d\n", len(items))
+	fmt.Fprintf(os.Stderr, "Successful:    %d\n", successCount)
+	if len(failures) > 0 {
+		fmt.Fprintf(os.Stderr, "Failed:        %d\n", len(failures))
+		fmt.Fprintf(os.Stderr, "\n⚠ Failed Entries Summary (%d failed):\n", len(failures))
+		for i, f := range failures {
+			fmt.Fprintf(os.Stderr, "  %d. %s (Priority=%d, Sequence=%d)\n     Error: %v\n",
+				i+1, filepath.Base(f.item.Entry.File), f.item.Priority, f.item.Sequence, f.err)
+		}
+	}
+	fmt.Fprintf(os.Stderr, "\n")
+
+	return nil
+}

cmd/relspec/root.go

@@ -64,6 +64,7 @@ func init() {
 	rootCmd.AddCommand(diffCmd)
 	rootCmd.AddCommand(inspectCmd)
 	rootCmd.AddCommand(scriptsCmd)
+	rootCmd.AddCommand(assetsCmd)
 	rootCmd.AddCommand(templCmd)
 	rootCmd.AddCommand(editCmd)
 	rootCmd.AddCommand(mergeCmd)

docs/SCRIPTS_COMMAND.md

@@ -85,6 +85,23 @@ migrations/
 
 All files will be found and executed in Priority→Sequence order regardless of directory structure.
 
+## External File Embedding
+
+Script SQL can embed nearby text or binary files before execution using `-- @embed` directives:
+
+```sql
+-- @embed: path=assets/message.txt var=:message mode=text
+-- @embed: path=assets/photo.bin var=:payload mode=base64
+INSERT INTO assets (message, payload)
+VALUES (:message, decode(:payload, 'base64')::bytea);
+```
+
+- `path`: File path resolved relative to the SQL file containing the directive
+- `var`: Named placeholder to replace, such as `:message`
+- `mode`: `text` embeds an escaped SQL string literal; `base64` embeds a base64 string literal
+
+The directive comment is removed from the SQL, and every matching placeholder is replaced before the script is listed or executed.
+
 ## Commands
 
 ### relspec scripts list

pkg/assetloader/embed.go

@@ -0,0 +1,165 @@
+package assetloader
+
+import (
+	"encoding/base64"
+	"fmt"
+	"os"
+	"path/filepath"
+	"regexp"
+	"strconv"
+	"strings"
+	"unicode/utf8"
+)
+
+const ScriptSourcePathMetadataKey = "source_path"
+
+var (
+	embedDirectivePattern = regexp.MustCompile(`(?m)^\s*--\s*@embed:\s*(.+?)\s*$`)
+	embedAttrPattern      = regexp.MustCompile(`([a-zA-Z_][a-zA-Z0-9_]*)=("[^"]*"|'[^']*'|\S+)`)
+	embedVarPattern       = regexp.MustCompile(`^:[a-zA-Z_][a-zA-Z0-9_]*$`)
+)
+
+// ProcessEmbedDirectives expands SQL comments in the form:
+//
+//	-- @embed: path=... var=:... mode=text|base64
+//
+// Paths are resolved relative to sqlPath. Text mode embeds a quoted UTF-8 SQL
+// string literal. Base64 mode embeds a quoted base64 literal suitable for
+// decode(:var, 'base64').
+func ProcessEmbedDirectives(sqlPath, sql string) (string, error) {
+	directives := embedDirectivePattern.FindAllStringSubmatch(sql, -1)
+	if len(directives) == 0 {
+		return sql, nil
+	}
+
+	if sqlPath == "" {
+		return "", fmt.Errorf("sql path is required for embed directives")
+	}
+
+	result := embedDirectivePattern.ReplaceAllString(sql, "")
+	for i, directive := range directives {
+		literal, placeholder, err := embedDirectiveLiteral(sqlPath, directive[1], i+1)
+		if err != nil {
+			return "", err
+		}
+		if !embedPlaceholderPattern(placeholder).MatchString(result) {
+			return "", fmt.Errorf("%s embed directive %d: placeholder %s not found", sqlPath, i+1, placeholder)
+		}
+		result = replaceEmbedPlaceholder(result, placeholder, literal)
+	}
+
+	return result, nil
+}
+
+func embedDirectiveLiteral(sqlPath, raw string, directiveNumber int) (string, string, error) {
+	attrs, err := parseEmbedAttrs(raw)
+	if err != nil {
+		return "", "", fmt.Errorf("%s embed directive %d: %w", sqlPath, directiveNumber, err)
+	}
+
+	pathValue := attrs["path"]
+	varValue := attrs["var"]
+	modeValue := attrs["mode"]
+	if pathValue == "" {
+		return "", "", fmt.Errorf("%s embed directive %d: missing path", sqlPath, directiveNumber)
+	}
+	if !embedVarPattern.MatchString(varValue) {
+		return "", "", fmt.Errorf("%s embed directive %d: var must be a named placeholder like :asset", sqlPath, directiveNumber)
+	}
+	if modeValue != "text" && modeValue != "base64" {
+		return "", "", fmt.Errorf("%s embed directive %d: mode must be text or base64", sqlPath, directiveNumber)
+	}
+
+	resolved := filepath.Join(filepath.Dir(sqlPath), filepath.Clean(pathValue))
+	data, err := os.ReadFile(resolved)
+	if err != nil {
+		return "", "", fmt.Errorf("%s embed directive %d: reading %s: %w", sqlPath, directiveNumber, resolved, err)
+	}
+
+	switch modeValue {
+	case "text":
+		if !utf8.Valid(data) {
+			return "", "", fmt.Errorf("%s embed directive %d: %s is not valid UTF-8", sqlPath, directiveNumber, resolved)
+		}
+		literal, err := sqlStringLiteral(string(data))
+		if err != nil {
+			return "", "", fmt.Errorf("%s embed directive %d: %w", sqlPath, directiveNumber, err)
+		}
+		return literal, varValue, nil
+	case "base64":
+		literal, err := sqlStringLiteral(base64.StdEncoding.EncodeToString(data))
+		if err != nil {
+			return "", "", fmt.Errorf("%s embed directive %d: %w", sqlPath, directiveNumber, err)
+		}
+		return literal, varValue, nil
+	default:
+		return "", "", fmt.Errorf("%s embed directive %d: mode must be text or base64", sqlPath, directiveNumber)
+	}
+}
+
+func parseEmbedAttrs(raw string) (map[string]string, error) {
+	attrs := map[string]string{}
+	matches := embedAttrPattern.FindAllStringSubmatchIndex(raw, -1)
+	if len(matches) == 0 {
+		return nil, fmt.Errorf("expected path, var, and mode attributes")
+	}
+
+	lastEnd := 0
+	for _, match := range matches {
+		gap := strings.TrimSpace(raw[lastEnd:match[0]])
+		if gap != "" {
+			return nil, fmt.Errorf("invalid attribute syntax near %q", gap)
+		}
+
+		key := raw[match[2]:match[3]]
+		value := raw[match[4]:match[5]]
+		if _, exists := attrs[key]; exists {
+			return nil, fmt.Errorf("duplicate attribute %q", key)
+		}
+		unquoted, err := unquoteEmbedValue(value)
+		if err != nil {
+			return nil, fmt.Errorf("invalid %s value: %w", key, err)
+		}
+		attrs[key] = unquoted
+		lastEnd = match[1]
+	}
+	if tail := strings.TrimSpace(raw[lastEnd:]); tail != "" {
+		return nil, fmt.Errorf("invalid attribute syntax near %q", tail)
+	}
+
+	for key := range attrs {
+		if key != "path" && key != "var" && key != "mode" {
+			return nil, fmt.Errorf("unknown attribute %q", key)
+		}
+	}
+
+	return attrs, nil
+}
+
+func unquoteEmbedValue(value string) (string, error) {
+	if len(value) < 2 {
+		return value, nil
+	}
+	if value[0] == '"' {
+		return strconv.Unquote(value)
+	}
+	if value[0] == '\'' && value[len(value)-1] == '\'' {
+		return value[1 : len(value)-1], nil
+	}
+	return value, nil
+}
+
+func sqlStringLiteral(value string) (string, error) {
+	if strings.ContainsRune(value, '\x00') {
+		return "", fmt.Errorf("embedded text contains NUL byte")
+	}
+	return "'" + strings.ReplaceAll(value, "'", "''") + "'", nil
+}
+
+func replaceEmbedPlaceholder(sql, placeholder, literal string) string {
+	return embedPlaceholderPattern(placeholder).ReplaceAllString(sql, "${1}"+literal+"${2}")
+}
+
+func embedPlaceholderPattern(placeholder string) *regexp.Regexp {
+	return regexp.MustCompile(`(^|[^a-zA-Z0-9_:])` + regexp.QuoteMeta(placeholder) + `([^a-zA-Z0-9_]|$)`)
+}

pkg/assetloader/embed_test.go

@@ -0,0 +1,143 @@
+package assetloader
+
+import (
+	"encoding/base64"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+)
+
+func TestProcessEmbedDirectives_TextLiteralEscapesQuotes(t *testing.T) {
+	dir := t.TempDir()
+	sqlPath := filepath.Join(dir, "1_001_seed.sql")
+	if err := os.WriteFile(filepath.Join(dir, "body.txt"), []byte("Line 1\nIt's fine"), 0o644); err != nil {
+		t.Fatal(err)
+	}
+
+	got, err := ProcessEmbedDirectives(sqlPath, `
+-- @embed: path=body.txt var=:body mode=text
+INSERT INTO notes (body) VALUES (:body);
+`)
+	if err != nil {
+		t.Fatalf("ProcessEmbedDirectives failed: %v", err)
+	}
+	if !strings.Contains(got, "VALUES ('Line 1\nIt''s fine');") {
+		t.Fatalf("embedded SQL did not contain escaped text literal:\n%s", got)
+	}
+	if strings.Contains(got, "VALUES (:body);") {
+		t.Fatalf("placeholder was not replaced:\n%s", got)
+	}
+}
+
+func TestProcessEmbedDirectives_Base64Literal(t *testing.T) {
+	dir := t.TempDir()
+	sqlPath := filepath.Join(dir, "1_001_seed.sql")
+	binary := []byte{0x00, 0xff, 0x10, 0x20}
+	if err := os.WriteFile(filepath.Join(dir, "blob.bin"), binary, 0o644); err != nil {
+		t.Fatal(err)
+	}
+
+	got, err := ProcessEmbedDirectives(sqlPath, `
+-- @embed: path=blob.bin var=:payload mode=base64
+INSERT INTO files (payload) VALUES (decode(:payload, 'base64')::bytea);
+`)
+	if err != nil {
+		t.Fatalf("ProcessEmbedDirectives failed: %v", err)
+	}
+	want := "decode('" + base64.StdEncoding.EncodeToString(binary) + "', 'base64')::bytea"
+	if !strings.Contains(got, want) {
+		t.Fatalf("embedded SQL did not contain base64 literal %q:\n%s", want, got)
+	}
+}
+
+func TestProcessEmbedDirectives_RelativeToSQLFile(t *testing.T) {
+	root := t.TempDir()
+	sqlDir := filepath.Join(root, "nested", "seed")
+	if err := os.MkdirAll(filepath.Join(sqlDir, "assets"), 0o755); err != nil {
+		t.Fatal(err)
+	}
+	sqlPath := filepath.Join(sqlDir, "1_001_seed.sql")
+	if err := os.WriteFile(filepath.Join(sqlDir, "assets", "body.txt"), []byte("relative body"), 0o644); err != nil {
+		t.Fatal(err)
+	}
+
+	got, err := ProcessEmbedDirectives(sqlPath, `
+-- @embed: path=assets/body.txt var=:body mode=text
+SELECT :body;
+`)
+	if err != nil {
+		t.Fatalf("ProcessEmbedDirectives failed: %v", err)
+	}
+	if !strings.Contains(got, "SELECT 'relative body';") {
+		t.Fatalf("path was not resolved relative to SQL file:\n%s", got)
+	}
+}
+
+func TestProcessEmbedDirectives_InvalidDirectiveAndFiles(t *testing.T) {
+	dir := t.TempDir()
+	sqlPath := filepath.Join(dir, "1_001_seed.sql")
+	if err := os.WriteFile(filepath.Join(dir, "body.txt"), []byte("ok"), 0o644); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.WriteFile(filepath.Join(dir, "binary.txt"), []byte{0xff, 0xfe}, 0o644); err != nil {
+		t.Fatal(err)
+	}
+
+	tests := []struct {
+		name string
+		sql  string
+	}{
+		{
+			name: "missing mode",
+			sql:  "-- @embed: path=body.txt var=:body\nSELECT :body;",
+		},
+		{
+			name: "invalid var",
+			sql:  "-- @embed: path=body.txt var=body mode=text\nSELECT :body;",
+		},
+		{
+			name: "missing file",
+			sql:  "-- @embed: path=missing.txt var=:body mode=text\nSELECT :body;",
+		},
+		{
+			name: "invalid utf8 text",
+			sql:  "-- @embed: path=binary.txt var=:body mode=text\nSELECT :body;",
+		},
+		{
+			name: "placeholder not found",
+			sql:  "-- @embed: path=body.txt var=:body mode=text\nSELECT 1;",
+		},
+		{
+			name: "unknown attribute",
+			sql:  "-- @embed: path=body.txt var=:body mode=text extra=yes\nSELECT :body;",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if _, err := ProcessEmbedDirectives(sqlPath, tt.sql); err == nil {
+				t.Fatal("expected error, got nil")
+			}
+		})
+	}
+}
+
+func TestProcessEmbedDirectives_DoesNotReplacePlaceholderPrefix(t *testing.T) {
+	dir := t.TempDir()
+	sqlPath := filepath.Join(dir, "1_001_seed.sql")
+	if err := os.WriteFile(filepath.Join(dir, "body.txt"), []byte("ok"), 0o644); err != nil {
+		t.Fatal(err)
+	}
+
+	got, err := ProcessEmbedDirectives(sqlPath, `
+-- @embed: path=body.txt var=:body mode=text
+SELECT :body, :body_extra;
+`)
+	if err != nil {
+		t.Fatalf("ProcessEmbedDirectives failed: %v", err)
+	}
+	if !strings.Contains(got, "SELECT 'ok', :body_extra;") {
+		t.Fatalf("placeholder boundary was not respected:\n%s", got)
+	}
+}

pkg/assetloader/executor.go

@@ -0,0 +1,107 @@
+package assetloader
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"path/filepath"
+	"regexp"
+	"strings"
+
+	"github.com/jackc/pgx/v5"
+)
+
+// namedPlaceholder matches :identifier patterns (but not ::cast syntax).
+var namedPlaceholder = regexp.MustCompile(`:([a-zA-Z_][a-zA-Z0-9_]*)`)
+
+// pgCastMarker temporarily replaces :: to protect PostgreSQL cast syntax.
+const pgCastMarker = "\x00PGCAST\x00"
+
+// BuildQuery converts a SQL call that uses :name named placeholders into a
+// pgx-compatible positional-parameter query ($1, $2, …) and returns the
+// corresponding argument slice.
+//
+// Built-in placeholders:
+//   - :bytes    → fileBytes ([]byte)
+//   - :filename → filename (string, base name only)
+//   - :any_key  → staticParams["any_key"] (string)
+//
+// A placeholder that appears more than once maps to the same $N. An unknown
+// placeholder (not built-in and not in staticParams) returns an error.
+// PostgreSQL cast syntax (::type) is left untouched.
+func BuildQuery(call string, fileBytes []byte, filename string, staticParams map[string]string) (string, []any, error) {
+	// Protect :: casts before running the placeholder regex.
+	protected := strings.ReplaceAll(call, "::", pgCastMarker)
+
+	paramIndex := map[string]int{} // name → 1-based position
+	var args []any
+	var firstErr error
+
+	result := namedPlaceholder.ReplaceAllStringFunc(protected, func(match string) string {
+		if firstErr != nil {
+			return match
+		}
+		name := match[1:] // strip leading ':'
+
+		// Return existing positional param for repeated placeholders.
+		if idx, seen := paramIndex[name]; seen {
+			return fmt.Sprintf("$%d", idx)
+		}
+
+		// Resolve the placeholder value.
+		var val any
+		switch name {
+		case "bytes":
+			val = fileBytes
+		case "filename":
+			val = filename
+		default:
+			if staticParams != nil {
+				if v, ok := staticParams[name]; ok {
+					val = v
+				}
+			}
+			if val == nil {
+				firstErr = fmt.Errorf("unknown placeholder %q in SQL call (not a built-in and not listed in params)", match)
+				return match
+			}
+		}
+
+		idx := len(args) + 1
+		paramIndex[name] = idx
+		args = append(args, val)
+		return fmt.Sprintf("$%d", idx)
+	})
+
+	if firstErr != nil {
+		return "", nil, firstErr
+	}
+
+	// Restore :: casts.
+	result = strings.ReplaceAll(result, pgCastMarker, "::")
+
+	return result, args, nil
+}
+
+// ExecuteItem reads the asset file referenced by item.Entry.File (which is the
+// absolute path set by ScanDir) and executes the configured SQL call via conn.
+// The file's raw bytes are bound as a []byte parameter — no encoding or escaping.
+func ExecuteItem(ctx context.Context, conn *pgx.Conn, item Item) error {
+	data, err := os.ReadFile(item.Entry.File)
+	if err != nil {
+		return fmt.Errorf("reading asset file %s: %w", item.Entry.File, err)
+	}
+
+	filename := filepath.Base(item.Entry.File)
+
+	sql, args, err := BuildQuery(item.Entry.Call, data, filename, item.Entry.Params)
+	if err != nil {
+		return fmt.Errorf("building query for %s: %w", filename, err)
+	}
+
+	if _, err := conn.Exec(ctx, sql, args...); err != nil {
+		return fmt.Errorf("executing asset %s: %w", filename, err)
+	}
+
+	return nil
+}

pkg/assetloader/loader.go

@@ -0,0 +1,200 @@
+// Package assetloader implements a native Go asset/file loader that binds
+// local binary and text files as pgx query parameters during database seeding.
+// Files are bound as actual []byte query parameters — never converted to SQL
+// text literals — so binary data stays byte-exact and no escaping is needed.
+//
+// Manifests are small YAML files (assets.yaml) that describe, per file, the
+// SQL call to invoke and the named placeholders for :bytes, :filename, and any
+// static column values. Manifests live inside directories that follow the same
+// {priority}_{sequence}_{name} naming convention used by the sqldir reader,
+// so asset-loading steps can be interleaved with SQL scripts in a migrate-apply
+// run.
+package assetloader
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"regexp"
+	"sort"
+	"strconv"
+	"strings"
+
+	"gopkg.in/yaml.v3"
+)
+
+// ManifestEntry describes a single file to load from an assets.yaml manifest.
+type ManifestEntry struct {
+	// File is the path to the asset file, relative to the manifest directory.
+	File string `yaml:"file"`
+	// Call is the SQL statement to execute. Use :bytes for file content,
+	// :filename for the base name, and :param_name for static params.
+	Call string `yaml:"call"`
+	// Params holds optional static named parameters referenced in Call.
+	Params map[string]string `yaml:"params,omitempty"`
+}
+
+// Item combines a manifest entry with its ordering metadata and the resolved
+// directory where the manifest and asset file reside.
+type Item struct {
+	// Priority and Sequence come from the parent directory's naming pattern.
+	Priority int
+	Sequence uint
+	// DirName is the last path component of the manifest's directory.
+	DirName string
+	// Dir is the absolute path to the directory containing assets.yaml and files.
+	Dir string
+	// Entry is the parsed manifest entry.
+	Entry ManifestEntry
+}
+
+// dirPattern matches {priority}_{sequence}_{name} or {priority}-{sequence}-{name}
+// directory names, e.g. "1_010_seed_templates" or "2-001-branding".
+var dirPattern = regexp.MustCompile(`^(\d+)[_-](\d+)[_-](.+)$`)
+
+// LoadManifest reads and parses the assets.yaml file in dir, returning
+// the ordered list of manifest entries. Returns an error if assets.yaml is
+// absent or contains invalid YAML.
+func LoadManifest(dir string) ([]ManifestEntry, error) {
+	manifestPath := filepath.Join(dir, "assets.yaml")
+	data, err := os.ReadFile(manifestPath)
+	if err != nil {
+		return nil, fmt.Errorf("reading %s: %w", manifestPath, err)
+	}
+
+	var entries []ManifestEntry
+	if err := yaml.Unmarshal(data, &entries); err != nil {
+		return nil, fmt.Errorf("parsing %s: %w", manifestPath, err)
+	}
+
+	return entries, nil
+}
+
+// ScanDir recursively walks baseDir, finds all assets.yaml manifests, resolves
+// each file entry (skipping symlinks and path traversal), and returns the
+// resulting Items sorted by (Priority, Sequence, DirName).
+//
+// Each manifest must reside in a directory whose name follows the
+// {priority}_{sequence}_{name} pattern. Manifests in directories that do not
+// follow this convention are assigned Priority=0, Sequence=0 and sorted last.
+func ScanDir(baseDir string) ([]Item, error) {
+	absBase, err := filepath.Abs(baseDir)
+	if err != nil {
+		return nil, fmt.Errorf("resolving base dir: %w", err)
+	}
+
+	var items []Item
+
+	err = filepath.WalkDir(absBase, func(path string, d os.DirEntry, walkErr error) error {
+		if walkErr != nil {
+			return walkErr
+		}
+		if d.IsDir() {
+			return nil
+		}
+		if d.Name() != "assets.yaml" {
+			return nil
+		}
+
+		manifestDir := filepath.Dir(path)
+		priority, sequence, dirName := parseDirName(filepath.Base(manifestDir))
+
+		entries, err := LoadManifest(manifestDir)
+		if err != nil {
+			return fmt.Errorf("loading manifest in %s: %w", manifestDir, err)
+		}
+
+		for _, entry := range entries {
+			if entry.File == "" || entry.Call == "" {
+				continue
+			}
+
+			// Resolve and validate the asset file path.
+			resolved, skip, err := resolveAssetPath(absBase, manifestDir, entry.File)
+			if err != nil {
+				return err
+			}
+			if skip {
+				continue
+			}
+
+			items = append(items, Item{
+				Priority: priority,
+				Sequence: sequence,
+				DirName:  dirName,
+				Dir:      manifestDir,
+				Entry: ManifestEntry{
+					File:   resolved, // absolute path, safe to read
+					Call:   entry.Call,
+					Params: entry.Params,
+				},
+			})
+		}
+
+		return nil
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	sort.SliceStable(items, func(i, j int) bool {
+		if items[i].Priority != items[j].Priority {
+			return items[i].Priority < items[j].Priority
+		}
+		if items[i].Sequence != items[j].Sequence {
+			return items[i].Sequence < items[j].Sequence
+		}
+		return items[i].DirName < items[j].DirName
+	})
+
+	return items, nil
+}
+
+// parseDirName extracts (priority, sequence, name) from a directory name that
+// follows the {priority}[_-]{sequence}[_-]{name} convention. Returns (0, 0, dir)
+// when the name does not match.
+func parseDirName(dir string) (priority int, sequence uint, name string) {
+	m := dirPattern.FindStringSubmatch(dir)
+	if m == nil {
+		return 0, 0, dir
+	}
+	p, _ := strconv.Atoi(m[1])
+	s, _ := strconv.ParseUint(m[2], 10, 64)
+	return p, uint(s), m[3]
+}
+
+// resolveAssetPath resolves a manifest-relative file path and checks that:
+//   - it does not escape the base directory (path traversal prevention)
+//   - none of its path components are symlinks
+//
+// Returns the absolute path, a skip flag (true when the entry should be silently
+// dropped), and any hard error.
+func resolveAssetPath(absBase, manifestDir, file string) (absPath string, skip bool, err error) {
+	// Clean and join before any symlink resolution so we can detect traversal.
+	joined := filepath.Join(manifestDir, filepath.Clean(file))
+
+	// Ensure the cleaned path is still inside absBase.
+	rel, err := filepath.Rel(absBase, joined)
+	if err != nil || strings.HasPrefix(rel, "..") {
+		// Path escapes the base directory; skip silently.
+		return "", true, nil
+	}
+
+	// Walk each component to detect symlinks.
+	parts := strings.Split(rel, string(filepath.Separator))
+	current := absBase
+	for _, part := range parts {
+		current = filepath.Join(current, part)
+		info, statErr := os.Lstat(current)
+		if statErr != nil {
+			// File doesn't exist; skip.
+			return "", true, nil
+		}
+		if info.Mode()&os.ModeSymlink != 0 {
+			// Symlink in path; skip silently.
+			return "", true, nil
+		}
+	}
+
+	return joined, false, nil
+}

pkg/assetloader/loader_test.go

@@ -0,0 +1,341 @@
+package assetloader_test
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+
+	"git.warky.dev/wdevs/relspecgo/pkg/assetloader"
+)
+
+func TestLoadManifest_ValidList(t *testing.T) {
+	dir := t.TempDir()
+	writeFile(t, dir, "assets.yaml", `
+- file: hello.txt
+  call: INSERT INTO files (name, data) VALUES (:filename, :bytes)
+- file: logo.png
+  call: UPDATE branding SET logo = :bytes WHERE id = 1
+`)
+	writeFile(t, dir, "hello.txt", "hello world")
+	writeFile(t, dir, "logo.png", "\x89PNG\r\n\x1a\n")
+
+	m, err := assetloader.LoadManifest(dir)
+	if err != nil {
+		t.Fatalf("LoadManifest failed: %v", err)
+	}
+	if len(m) != 2 {
+		t.Fatalf("expected 2 entries, got %d", len(m))
+	}
+	if m[0].File != "hello.txt" {
+		t.Errorf("entry 0 file: got %q, want %q", m[0].File, "hello.txt")
+	}
+	if m[1].File != "logo.png" {
+		t.Errorf("entry 1 file: got %q, want %q", m[1].File, "logo.png")
+	}
+}
+
+func TestLoadManifest_WithStaticParams(t *testing.T) {
+	dir := t.TempDir()
+	writeFile(t, dir, "assets.yaml", `
+- file: template.md
+  call: INSERT INTO templates (owner_id, name, data) VALUES (:owner_id, :filename, :bytes)
+  params:
+    owner_id: "42"
+`)
+	writeFile(t, dir, "template.md", "# Template")
+
+	m, err := assetloader.LoadManifest(dir)
+	if err != nil {
+		t.Fatalf("LoadManifest failed: %v", err)
+	}
+	if len(m) != 1 {
+		t.Fatalf("expected 1 entry, got %d", len(m))
+	}
+	if m[0].Params["owner_id"] != "42" {
+		t.Errorf("static param owner_id: got %q, want %q", m[0].Params["owner_id"], "42")
+	}
+}
+
+func TestLoadManifest_MissingFile(t *testing.T) {
+	dir := t.TempDir()
+	// No assets.yaml present
+	_, err := assetloader.LoadManifest(dir)
+	if err == nil {
+		t.Fatal("expected error for missing assets.yaml, got nil")
+	}
+}
+
+func TestLoadManifest_InvalidYAML(t *testing.T) {
+	dir := t.TempDir()
+	writeFile(t, dir, "assets.yaml", `{not: [valid yaml`)
+	_, err := assetloader.LoadManifest(dir)
+	if err == nil {
+		t.Fatal("expected error for invalid YAML, got nil")
+	}
+}
+
+func TestScanDir_FindsManifests(t *testing.T) {
+	root := t.TempDir()
+
+	// Directory named with priority-sequence pattern
+	dir1 := filepath.Join(root, "1_010_seed_templates")
+	if err := os.MkdirAll(dir1, 0o755); err != nil {
+		t.Fatal(err)
+	}
+	writeFile(t, dir1, "assets.yaml", `
+- file: a.txt
+  call: INSERT INTO t (data) VALUES (:bytes)
+`)
+	writeFile(t, dir1, "a.txt", "aaa")
+
+	dir2 := filepath.Join(root, "2_001_branding")
+	if err := os.MkdirAll(dir2, 0o755); err != nil {
+		t.Fatal(err)
+	}
+	writeFile(t, dir2, "assets.yaml", `
+- file: logo.png
+  call: UPDATE branding SET logo = :bytes
+`)
+	writeFile(t, dir2, "logo.png", "PNG")
+
+	items, err := assetloader.ScanDir(root)
+	if err != nil {
+		t.Fatalf("ScanDir failed: %v", err)
+	}
+	if len(items) != 2 {
+		t.Fatalf("expected 2 items, got %d", len(items))
+	}
+	// Should be ordered by priority then sequence
+	if items[0].Priority != 1 || items[0].Sequence != 10 {
+		t.Errorf("item[0]: got priority=%d seq=%d, want 1,10", items[0].Priority, items[0].Sequence)
+	}
+	if items[1].Priority != 2 || items[1].Sequence != 1 {
+		t.Errorf("item[1]: got priority=%d seq=%d, want 2,1", items[1].Priority, items[1].Sequence)
+	}
+}
+
+func TestScanDir_OrdersByPriorityThenSequence(t *testing.T) {
+	root := t.TempDir()
+
+	for _, d := range []string{"2_002_b", "1_001_a", "2_001_c", "1_002_d"} {
+		dir := filepath.Join(root, d)
+		if err := os.MkdirAll(dir, 0o755); err != nil {
+			t.Fatal(err)
+		}
+		writeFile(t, dir, "assets.yaml", `
+- file: x.txt
+  call: SELECT :bytes
+`)
+		writeFile(t, dir, "x.txt", "x")
+	}
+
+	items, err := assetloader.ScanDir(root)
+	if err != nil {
+		t.Fatalf("ScanDir failed: %v", err)
+	}
+	if len(items) != 4 {
+		t.Fatalf("expected 4 items, got %d", len(items))
+	}
+
+	type ps struct{ p int; s uint }
+	want := []ps{{1, 1}, {1, 2}, {2, 1}, {2, 2}}
+	for i, w := range want {
+		got := ps{items[i].Priority, items[i].Sequence}
+		if got != w {
+			t.Errorf("items[%d]: got {%d,%d}, want {%d,%d}", i, got.p, got.s, w.p, w.s)
+		}
+	}
+}
+
+func TestScanDir_SkipsSymlinks(t *testing.T) {
+	root := t.TempDir()
+
+	dir1 := filepath.Join(root, "1_001_real")
+	if err := os.MkdirAll(dir1, 0o755); err != nil {
+		t.Fatal(err)
+	}
+	writeFile(t, dir1, "assets.yaml", `
+- file: a.txt
+  call: SELECT :bytes
+`)
+	writeFile(t, dir1, "a.txt", "real")
+
+	// Symlink to an asset file - should be skipped during file read
+	realFile := filepath.Join(root, "real.txt")
+	writeFile(t, root, "real.txt", "symlink target")
+	symlink := filepath.Join(dir1, "link.txt")
+	if err := os.Symlink(realFile, symlink); err != nil {
+		t.Skip("symlinks not supported:", err)
+	}
+
+	// Add a manifest entry that references the symlink
+	writeFile(t, dir1, "assets.yaml", `
+- file: a.txt
+  call: SELECT :bytes
+- file: link.txt
+  call: SELECT :bytes
+`)
+
+	items, err := assetloader.ScanDir(root)
+	if err != nil {
+		t.Fatalf("ScanDir failed: %v", err)
+	}
+	// The symlink entry should be skipped; only a.txt should remain
+	if len(items) != 1 {
+		t.Fatalf("expected 1 item after symlink skip, got %d", len(items))
+	}
+	if filepath.Base(items[0].Entry.File) != "a.txt" {
+		t.Errorf("expected non-symlink entry, got %q", items[0].Entry.File)
+	}
+}
+
+func TestScanDir_RejectsPathTraversal(t *testing.T) {
+	root := t.TempDir()
+
+	dir1 := filepath.Join(root, "1_001_evil")
+	if err := os.MkdirAll(dir1, 0o755); err != nil {
+		t.Fatal(err)
+	}
+	writeFile(t, dir1, "assets.yaml", `
+- file: ../../etc/passwd
+  call: SELECT :bytes
+`)
+
+	items, err := assetloader.ScanDir(root)
+	if err != nil {
+		t.Fatalf("ScanDir failed: %v", err)
+	}
+	// Path traversal entry should be skipped
+	if len(items) != 0 {
+		t.Fatalf("expected 0 items after path traversal rejection, got %d", len(items))
+	}
+}
+
+func TestBuildQuery_BasicPlaceholders(t *testing.T) {
+	sql, args, err := assetloader.BuildQuery(
+		"INSERT INTO t (name, data) VALUES (:filename, :bytes)",
+		[]byte("hello"),
+		"hello.txt",
+		nil,
+	)
+	if err != nil {
+		t.Fatalf("BuildQuery failed: %v", err)
+	}
+	if sql != "INSERT INTO t (name, data) VALUES ($1, $2)" {
+		t.Errorf("unexpected SQL: %s", sql)
+	}
+	if len(args) != 2 {
+		t.Fatalf("expected 2 args, got %d", len(args))
+	}
+	if string(args[0].(string)) != "hello.txt" {
+		t.Errorf("args[0]: got %q, want %q", args[0], "hello.txt")
+	}
+	if string(args[1].([]byte)) != "hello" {
+		t.Errorf("args[1]: got %v, want %v", args[1], []byte("hello"))
+	}
+}
+
+func TestBuildQuery_StaticParams(t *testing.T) {
+	sql, args, err := assetloader.BuildQuery(
+		"INSERT INTO t (owner, name, data) VALUES (:owner_id, :filename, :bytes)",
+		[]byte("data"),
+		"file.bin",
+		map[string]string{"owner_id": "99"},
+	)
+	if err != nil {
+		t.Fatalf("BuildQuery failed: %v", err)
+	}
+	if sql != "INSERT INTO t (owner, name, data) VALUES ($1, $2, $3)" {
+		t.Errorf("unexpected SQL: %s", sql)
+	}
+	if len(args) != 3 {
+		t.Fatalf("expected 3 args, got %d: %v", len(args), args)
+	}
+	if args[0].(string) != "99" {
+		t.Errorf("args[0]: got %q, want %q", args[0], "99")
+	}
+}
+
+func TestBuildQuery_RepeatedPlaceholder(t *testing.T) {
+	sql, args, err := assetloader.BuildQuery(
+		"SELECT length(:bytes), encode(:bytes, 'base64')",
+		[]byte("abc"),
+		"f.bin",
+		nil,
+	)
+	if err != nil {
+		t.Fatalf("BuildQuery failed: %v", err)
+	}
+	// :bytes appears twice but maps to same $1
+	if sql != "SELECT length($1), encode($1, 'base64')" {
+		t.Errorf("unexpected SQL: %s", sql)
+	}
+	if len(args) != 1 {
+		t.Fatalf("expected 1 arg, got %d", len(args))
+	}
+}
+
+func TestBuildQuery_PostgresCastNotMatched(t *testing.T) {
+	// ::text should NOT be treated as a placeholder
+	sql, args, err := assetloader.BuildQuery(
+		"SELECT :bytes::text, :filename",
+		[]byte("data"),
+		"f.txt",
+		nil,
+	)
+	if err != nil {
+		t.Fatalf("BuildQuery failed: %v", err)
+	}
+	if sql != "SELECT $1::text, $2" {
+		t.Errorf("unexpected SQL: %s", sql)
+	}
+	if len(args) != 2 {
+		t.Fatalf("expected 2 args, got %d", len(args))
+	}
+}
+
+func TestBuildQuery_UnknownPlaceholder(t *testing.T) {
+	_, _, err := assetloader.BuildQuery(
+		"SELECT :unknown_param",
+		[]byte("data"),
+		"f.txt",
+		nil,
+	)
+	if err == nil {
+		t.Fatal("expected error for unknown placeholder, got nil")
+	}
+}
+
+func TestBuildQuery_BinaryFileByteExact(t *testing.T) {
+	// Binary data with null bytes, high bytes - must pass through unchanged
+	binary := []byte{0x00, 0xFF, 0x80, 0x01, 0xFE}
+	_, args, err := assetloader.BuildQuery(
+		"INSERT INTO blobs (data) VALUES (:bytes)",
+		binary,
+		"blob.bin",
+		nil,
+	)
+	if err != nil {
+		t.Fatalf("BuildQuery failed: %v", err)
+	}
+	if len(args) != 1 {
+		t.Fatalf("expected 1 arg")
+	}
+	got := args[0].([]byte)
+	if len(got) != len(binary) {
+		t.Fatalf("byte count: got %d, want %d", len(got), len(binary))
+	}
+	for i, b := range binary {
+		if got[i] != b {
+			t.Errorf("byte[%d]: got 0x%02x, want 0x%02x", i, got[i], b)
+		}
+	}
+}
+
+// writeFile is a test helper that writes content to a file.
+func writeFile(t *testing.T, dir, name, content string) {
+	t.Helper()
+	if err := os.WriteFile(filepath.Join(dir, name), []byte(content), 0o644); err != nil {
+		t.Fatalf("writeFile %s: %v", name, err)
+	}
+}

pkg/models/models.go

@@ -350,16 +350,17 @@ const (
 // Script represents a database migration or initialization script.
 // Scripts can have dependencies and rollback capabilities.
 type Script struct {
-	Name        string   `json:"name" yaml:"name" xml:"name"`
+	Name        string         `json:"name" yaml:"name" xml:"name"`
-	Description string   `json:"description" yaml:"description" xml:"description"`
+	Description string         `json:"description" yaml:"description" xml:"description"`
-	SQL         string   `json:"sql" yaml:"sql" xml:"sql"`
+	SQL         string         `json:"sql" yaml:"sql" xml:"sql"`
-	Rollback    string   `json:"rollback,omitempty" yaml:"rollback,omitempty" xml:"rollback,omitempty"`
+	Rollback    string         `json:"rollback,omitempty" yaml:"rollback,omitempty" xml:"rollback,omitempty"`
-	RunAfter    []string `json:"run_after,omitempty" yaml:"run_after,omitempty" xml:"run_after,omitempty"`
+	RunAfter    []string       `json:"run_after,omitempty" yaml:"run_after,omitempty" xml:"run_after,omitempty"`
-	Schema      string   `json:"schema,omitempty" yaml:"schema,omitempty" xml:"schema,omitempty"`
+	Schema      string         `json:"schema,omitempty" yaml:"schema,omitempty" xml:"schema,omitempty"`
-	Version     string   `json:"version,omitempty" yaml:"version,omitempty" xml:"version,omitempty"`
+	Version     string         `json:"version,omitempty" yaml:"version,omitempty" xml:"version,omitempty"`
-	Priority    int      `json:"priority,omitempty" yaml:"priority,omitempty" xml:"priority,omitempty"`
+	Priority    int            `json:"priority,omitempty" yaml:"priority,omitempty" xml:"priority,omitempty"`
-	Sequence    uint     `json:"sequence,omitempty" yaml:"sequence,omitempty" xml:"sequence,omitempty"`
+	Sequence    uint           `json:"sequence,omitempty" yaml:"sequence,omitempty" xml:"sequence,omitempty"`
-	GUID        string   `json:"guid" yaml:"guid" xml:"guid"`
+	GUID        string         `json:"guid" yaml:"guid" xml:"guid"`
+	Metadata    map[string]any `json:"metadata,omitempty" yaml:"metadata,omitempty" xml:"-"`
 }
 
 // SQLName returns the script name in lowercase for SQL compatibility.
@@ -468,6 +469,7 @@ func InitScript(name string) *Script {
 	return &Script{
 		Name:     name,
 		RunAfter: make([]string, 0),
+		Metadata: make(map[string]any),
 		GUID:     uuid.New().String(),
 	}
 }

pkg/readers/sqldir/README.md

@@ -45,6 +45,21 @@ migrations/
 - `1_001_test.txt` - Wrong extension
 - `readme.md` - Not a SQL file
 
+## External File Embedding
+
+SQL files can include external files with `-- @embed` directives. File paths are resolved relative to the SQL file being read.
+
+```sql
+-- @embed: path=assets/message.txt var=:message mode=text
+-- @embed: path=assets/payload.bin var=:payload mode=base64
+INSERT INTO assets (message, payload)
+VALUES (:message, decode(:payload, 'base64')::bytea);
+```
+
+- `mode=text` reads UTF-8 text and replaces the placeholder with an escaped SQL string literal.
+- `mode=base64` reads any bytes and replaces the placeholder with a base64 SQL string literal.
+- The placeholder must be named, for example `:message`, and must appear in the SQL body.
+
 ## Usage
 
 ### Basic Usage

pkg/readers/sqldir/reader.go

@@ -7,6 +7,7 @@ import (
 	"regexp"
 	"strconv"
 
+	"git.warky.dev/wdevs/relspecgo/pkg/assetloader"
 	"git.warky.dev/wdevs/relspecgo/pkg/models"
 	"git.warky.dev/wdevs/relspecgo/pkg/readers"
 )
@@ -151,6 +152,10 @@ func (r *Reader) readScripts() ([]*models.Script, error) {
 		if err != nil {
 			return fmt.Errorf("failed to read file %s: %w", path, err)
 		}
+		sql, err := assetloader.ProcessEmbedDirectives(path, string(content))
+		if err != nil {
+			return err
+		}
 
 		// Get relative path from base directory
 		relPath, err := filepath.Rel(r.options.FilePath, path)
@@ -161,9 +166,10 @@ func (r *Reader) readScripts() ([]*models.Script, error) {
 		// Create Script model
 		script := models.InitScript(name)
 		script.Description = fmt.Sprintf("SQL script from %s", relPath)
-		script.SQL = string(content)
+		script.SQL = sql
 		script.Priority = priority
 		script.Sequence = uint(sequence)
+		script.Metadata[assetloader.ScriptSourcePathMetadataKey] = path
 
 		scripts = append(scripts, script)
 

pkg/readers/sqldir/reader_test.go

@@ -1,8 +1,10 @@
 package sqldir
 
 import (
+	"encoding/base64"
 	"os"
 	"path/filepath"
+	"strings"
 	"testing"
 
 	"git.warky.dev/wdevs/relspecgo/pkg/readers"
@@ -18,12 +20,12 @@ func TestReader_ReadDatabase(t *testing.T) {
 
 	// Create test SQL files with both underscore and hyphen separators
 	testFiles := map[string]string{
-		"1_001_create_users.sql":  "CREATE TABLE users (id SERIAL PRIMARY KEY, name TEXT);",
+		"1_001_create_users.sql":   "CREATE TABLE users (id SERIAL PRIMARY KEY, name TEXT);",
-		"1_002_create_posts.sql":  "CREATE TABLE posts (id SERIAL PRIMARY KEY, user_id INT);",
+		"1_002_create_posts.sql":   "CREATE TABLE posts (id SERIAL PRIMARY KEY, user_id INT);",
-		"2_001_add_indexes.sql":   "CREATE INDEX idx_posts_user_id ON posts(user_id);",
+		"2_001_add_indexes.sql":    "CREATE INDEX idx_posts_user_id ON posts(user_id);",
-		"1_003_seed_data.pgsql":   "INSERT INTO users (name) VALUES ('Alice'), ('Bob');",
+		"1_003_seed_data.pgsql":    "INSERT INTO users (name) VALUES ('Alice'), ('Bob');",
 		"10-10-create-newid.pgsql": "CREATE TABLE newid (id SERIAL PRIMARY KEY);",
-		"2-005-add-column.sql":    "ALTER TABLE users ADD COLUMN email TEXT;",
+		"2-005-add-column.sql":     "ALTER TABLE users ADD COLUMN email TEXT;",
 	}
 
 	for filename, content := range testFiles {
@@ -267,10 +269,10 @@ func TestReader_HyphenFormat(t *testing.T) {
 
 	// Create test files with hyphen separators
 	testFiles := map[string]string{
-		"1-001-create-table.sql":  "CREATE TABLE test (id INT);",
+		"1-001-create-table.sql":   "CREATE TABLE test (id INT);",
-		"1-002-insert-data.pgsql": "INSERT INTO test VALUES (1);",
+		"1-002-insert-data.pgsql":  "INSERT INTO test VALUES (1);",
 		"10-10-create-newid.pgsql": "CREATE TABLE newid (id SERIAL);",
-		"2-005-add-index.sql":     "CREATE INDEX idx_test ON test(id);",
+		"2-005-add-index.sql":      "CREATE INDEX idx_test ON test(id);",
 	}
 
 	for filename, content := range testFiles {
@@ -301,10 +303,10 @@ func TestReader_HyphenFormat(t *testing.T) {
 		priority int
 		sequence uint
 	}{
-		"create-table":  {1, 1},
+		"create-table": {1, 1},
-		"insert-data":   {1, 2},
+		"insert-data":  {1, 2},
-		"add-index":     {2, 5},
+		"add-index":    {2, 5},
-		"create-newid":  {10, 10},
+		"create-newid": {10, 10},
 	}
 
 	for _, script := range schema.Scripts {
@@ -435,3 +437,61 @@ func TestReader_SkipSymlinks(t *testing.T) {
 		t.Error("Symlink script should have been skipped but was found")
 	}
 }
+
+func TestReader_EmbedDirectives(t *testing.T) {
+	tempDir := t.TempDir()
+	assetDir := filepath.Join(tempDir, "assets")
+	if err := os.MkdirAll(assetDir, 0o755); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.WriteFile(filepath.Join(assetDir, "message.txt"), []byte("Reader's text"), 0o644); err != nil {
+		t.Fatal(err)
+	}
+	binary := []byte{0x00, 0x01, 0xfe, 0xff}
+	if err := os.WriteFile(filepath.Join(assetDir, "payload.bin"), binary, 0o644); err != nil {
+		t.Fatal(err)
+	}
+	sql := `
+-- @embed: path=assets/message.txt var=:message mode=text
+-- @embed: path=assets/payload.bin var=:payload mode=base64
+INSERT INTO assets (message, payload) VALUES (:message, decode(:payload, 'base64')::bytea);
+`
+	if err := os.WriteFile(filepath.Join(tempDir, "1_001_embed.sql"), []byte(sql), 0o644); err != nil {
+		t.Fatal(err)
+	}
+
+	reader := NewReader(&readers.ReaderOptions{FilePath: tempDir})
+	db, err := reader.ReadDatabase()
+	if err != nil {
+		t.Fatalf("ReadDatabase failed: %v", err)
+	}
+	if len(db.Schemas[0].Scripts) != 1 {
+		t.Fatalf("expected 1 script, got %d", len(db.Schemas[0].Scripts))
+	}
+
+	got := db.Schemas[0].Scripts[0].SQL
+	if !strings.Contains(got, "'Reader''s text'") {
+		t.Fatalf("text asset was not embedded as an escaped SQL literal:\n%s", got)
+	}
+	wantBase64 := "decode('" + base64.StdEncoding.EncodeToString(binary) + "', 'base64')::bytea"
+	if !strings.Contains(got, wantBase64) {
+		t.Fatalf("binary asset was not embedded as a base64 SQL literal:\n%s", got)
+	}
+}
+
+func TestReader_EmbedDirectiveErrors(t *testing.T) {
+	tempDir := t.TempDir()
+	sql := "-- @embed: path=missing.txt var=:message mode=text\nSELECT :message;"
+	if err := os.WriteFile(filepath.Join(tempDir, "1_001_embed.sql"), []byte(sql), 0o644); err != nil {
+		t.Fatal(err)
+	}
+
+	reader := NewReader(&readers.ReaderOptions{FilePath: tempDir})
+	_, err := reader.ReadDatabase()
+	if err == nil {
+		t.Fatal("expected embed error, got nil")
+	}
+	if !strings.Contains(err.Error(), "missing.txt") {
+		t.Fatalf("expected missing file in error, got %v", err)
+	}
+}

pkg/writers/sqlexec/writer.go

@@ -7,6 +7,7 @@ import (
 
 	"github.com/jackc/pgx/v5"
 
+	"git.warky.dev/wdevs/relspecgo/pkg/assetloader"
 	"git.warky.dev/wdevs/relspecgo/pkg/models"
 	"git.warky.dev/wdevs/relspecgo/pkg/pgsql"
 	"git.warky.dev/wdevs/relspecgo/pkg/writers"
@@ -138,7 +139,28 @@ func (w *Writer) executeScripts(ctx context.Context, conn *pgx.Conn, scripts []*
 			script.Name, script.Priority, script.Sequence)
 
 		// Execute the SQL script
-		_, err := conn.Exec(ctx, script.SQL)
+		sql, err := processEmbedDirectives(script)
+		if err != nil {
+			if ignoreErrors {
+				fmt.Printf("⚠ Error preparing %s: %v (continuing due to --ignore-errors)\n", script.Name, err)
+				failedScripts = append(failedScripts, struct {
+					name     string
+					priority int
+					sequence uint
+					err      error
+				}{
+					name:     script.Name,
+					priority: script.Priority,
+					sequence: script.Sequence,
+					err:      err,
+				})
+				continue
+			}
+			return fmt.Errorf("script %s (Priority=%d, Sequence=%d): %w",
+				script.Name, script.Priority, script.Sequence, err)
+		}
+
+		_, err = conn.Exec(ctx, sql)
 		if err != nil {
 			if ignoreErrors {
 				fmt.Printf("⚠ Error executing %s: %v (continuing due to --ignore-errors)\n", script.Name, err)
@@ -179,3 +201,11 @@ func (w *Writer) executeScripts(ctx context.Context, conn *pgx.Conn, scripts []*
 
 	return nil
 }
+
+func processEmbedDirectives(script *models.Script) (string, error) {
+	sqlPath, _ := script.Metadata[assetloader.ScriptSourcePathMetadataKey].(string)
+	if sqlPath == "" {
+		return script.SQL, nil
+	}
+	return assetloader.ProcessEmbedDirectives(sqlPath, script.SQL)
+}

pkg/writers/sqlexec/writer_test.go

@@ -1,8 +1,12 @@
 package sqlexec
 
 import (
+	"os"
+	"path/filepath"
+	"strings"
 	"testing"
 
+	"git.warky.dev/wdevs/relspecgo/pkg/assetloader"
 	"git.warky.dev/wdevs/relspecgo/pkg/models"
 	"git.warky.dev/wdevs/relspecgo/pkg/writers"
 )
@@ -216,3 +220,36 @@ func TestWriter_WriteSchema_EmptyScripts(t *testing.T) {
 //     // Verify results
 //     // Cleanup
 // }
+
+func TestProcessEmbedDirectives_UsesScriptSourcePath(t *testing.T) {
+	dir := t.TempDir()
+	sqlPath := filepath.Join(dir, "1_001_seed.sql")
+	if err := os.WriteFile(filepath.Join(dir, "body.txt"), []byte("writer text"), 0o644); err != nil {
+		t.Fatal(err)
+	}
+
+	script := models.InitScript("seed")
+	script.SQL = "-- @embed: path=body.txt var=:body mode=text\nSELECT :body;"
+	script.Metadata[assetloader.ScriptSourcePathMetadataKey] = sqlPath
+
+	got, err := processEmbedDirectives(script)
+	if err != nil {
+		t.Fatalf("processEmbedDirectives failed: %v", err)
+	}
+	if !strings.Contains(got, "SELECT 'writer text';") {
+		t.Fatalf("script embed directive was not processed:\n%s", got)
+	}
+}
+
+func TestProcessEmbedDirectives_NoSourcePathLeavesSQLUnchanged(t *testing.T) {
+	script := models.InitScript("seed")
+	script.SQL = "-- @embed: path=missing.txt var=:body mode=text\nSELECT :body;"
+
+	got, err := processEmbedDirectives(script)
+	if err != nil {
+		t.Fatalf("processEmbedDirectives failed: %v", err)
+	}
+	if got != script.SQL {
+		t.Fatalf("expected unchanged SQL without source path, got:\n%s", got)
+	}
+}

test_data/asset-smoke/1_010_templates/assets.yaml

@@ -0,0 +1,6 @@
+- file: hello.md
+  call: |
+    INSERT INTO docs (name, content)
+    VALUES (:filename, :bytes::text)
+- file: logo.png
+  call: UPDATE branding SET logo = :bytes WHERE id = 1

test_data/asset-smoke/1_010_templates/hello.md

@@ -0,0 +1 @@
+# Hello World

test_data/asset-smoke/1_010_templates/logo.png

@@ -0,0 +1 @@
+PNG_PLACEHOLDER

test_data/asset-smoke/2_001_branding/assets.yaml

@@ -0,0 +1,4 @@
+- file: banner.txt
+  call: INSERT INTO banners (data) VALUES (:bytes)
+  params:
+    owner_id: "1"

test_data/asset-smoke/2_001_branding/banner.txt

@@ -0,0 +1 @@
+BANNER CONTENT