Make run identities collision-resistant and outputs exclusive

internal/core/debugbundle/bundle.go

@@ -9,47 +9,49 @@ import (
 	"time"
 )
 
-const maxCreateAttempts = 16
-
-var utcNow = func() time.Time { return time.Now().UTC() }
-
 type Bundle struct {
 	path, summaryRoot, traceRoot string
 	createdAt                    time.Time
 }
 
-func Allocate(parent string) (*Bundle, error) {
+func Allocate(parent, runID string, startedAt time.Time) (*Bundle, error) {
 	parent = strings.TrimSpace(parent)
 	if parent == "" {
 		return nil, fmt.Errorf("debug parent must not be empty")
 	}
+	if err := validateRunID(runID); err != nil {
+		return nil, err
+	}
 	if err := os.MkdirAll(parent, 0o700); err != nil {
 		return nil, fmt.Errorf("create debug parent %q: %w", parent, err)
 	}
-	var last string
-	for attempt := 0; attempt < maxCreateAttempts; attempt++ {
-		createdAt := utcNow()
-		runID := fmt.Sprintf("run-%d", createdAt.UnixNano())
-		path := filepath.Join(parent, runID)
-		last = path
-		if err := os.Mkdir(path, 0o700); err != nil {
-			if os.IsExist(err) {
-				continue
-			}
-			return nil, fmt.Errorf("create debug bundle %q: %w", path, err)
+	path := filepath.Join(parent, runID)
+	if err := os.Mkdir(path, 0o700); err != nil {
+		if os.IsExist(err) {
+			return nil, fmt.Errorf("debug bundle %q already exists", path)
 		}
-		summary, trace := filepath.Join(path, "summary"), filepath.Join(path, "trace")
-		if err := os.Mkdir(summary, 0o700); err != nil {
-			_ = os.Remove(path)
-			return nil, fmt.Errorf("create debug summary %q: %w", summary, err)
-		}
-		if err := os.Mkdir(trace, 0o700); err != nil {
-			_ = os.RemoveAll(path)
-			return nil, fmt.Errorf("create debug trace %q: %w", trace, err)
-		}
-		return &Bundle{path: path, summaryRoot: summary, traceRoot: trace, createdAt: createdAt}, nil
+		return nil, fmt.Errorf("create debug bundle %q: %w", path, err)
 	}
-	return nil, fmt.Errorf("create debug bundle %q: exhausted unique run ID attempts", last)
+	summary, trace := filepath.Join(path, "summary"), filepath.Join(path, "trace")
+	if err := os.Mkdir(summary, 0o700); err != nil {
+		_ = os.Remove(path)
+		return nil, fmt.Errorf("create debug summary %q: %w", summary, err)
+	}
+	if err := os.Mkdir(trace, 0o700); err != nil {
+		_ = os.RemoveAll(path)
+		return nil, fmt.Errorf("create debug trace %q: %w", trace, err)
+	}
+	return &Bundle{path: path, summaryRoot: summary, traceRoot: trace, createdAt: startedAt}, nil
+}
+
+func validateRunID(runID string) error {
+	if runID == "" {
+		return fmt.Errorf("debug run ID must not be empty")
+	}
+	if runID != strings.TrimSpace(runID) || strings.ContainsAny(runID, `/\\`) || filepath.IsAbs(runID) || filepath.Clean(runID) != runID || runID == "." || runID == ".." {
+		return fmt.Errorf("debug run ID %q must be one safe path component", runID)
+	}
+	return nil
 }
 func (b *Bundle) Path() string {
 	if b == nil {