chaindata/chaindata.go

@@ -2,6 +2,7 @@ package chaindata
 
 import (
 	"errors"
+	"io"
 	"os"
 	"path/filepath"
 	"runtime"
@@ -27,7 +28,9 @@ func IsFixture(chain string) bool {
 	return has
 }
 
-// GetFixture returns the absolute paths to fixture chaindata for the given name.
+// GetFixture returns the paths to the fixture chaindata for the given name.  This copies the
+// fixture data and returns paths to temp directories, due to the fact that Go modules are installed
+// read-only and Leveldb will attempt to create lock files when opening a DB.
 func GetFixture(chain string) (*Paths, error) {
 	if !IsFixture(chain) {
 		return nil, errors.New("no fixture named " + chain)
@@ -39,11 +42,71 @@ func GetFixture(chain string) (*Paths, error) {
 	}
 
 	chaindataPath := filepath.Join(filepath.Dir(thisPath), "_data", chain)
-	ancientdataPath := filepath.Join(chaindataPath, "ancient")
-
 	if _, err := os.Stat(chaindataPath); err != nil {
 		return nil, errors.New("cannot access chaindata at " + chaindataPath)
 	}
 
-	return &Paths{chaindataPath, ancientdataPath}, nil
+	// Copy chaindata directory to a temporary directory
+	// Note that we assume the ancient path is a subdirectory
+	copyTo := filepath.Join(os.TempDir(), chain)
+	if err := copyDir(chaindataPath, copyTo); err != nil {
+		return nil, err
+	}
+	ancientCopy := filepath.Join(copyTo, "ancient")
+
+	return &Paths{copyTo, ancientCopy}, nil
+}
+
+func copyDir(src, dest string) error {
+	err := os.MkdirAll(dest, 0755)
+	if err != nil {
+		return err
+	}
+
+	srcDir, err := os.Open(src)
+	if err != nil {
+		return err
+	}
+	defer srcDir.Close()
+
+	fileInfos, err := srcDir.Readdir(-1)
+	if err != nil {
+		return err
+	}
+
+	for _, fileInfo := range fileInfos {
+		srcPath := filepath.Join(src, fileInfo.Name())
+		destPath := filepath.Join(dest, fileInfo.Name())
+
+		if fileInfo.IsDir() {
+			if err := copyDir(srcPath, destPath); err != nil {
+				return err
+			}
+		} else {
+			if err := copyFile(srcPath, destPath); err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}
+
+func copyFile(src, dest string) error {
+	srcFile, err := os.Open(src)
+	if err != nil {
+		return err
+	}
+	defer srcFile.Close()
+
+	destFile, err := os.Create(dest)
+	if err != nil {
+		return err
+	}
+	defer destFile.Close()
+
+	_, err = io.Copy(destFile, srcFile)
+	if err != nil {
+		return err
+	}
+	return nil
 }