Initial commit

Proof-of-concept implementation. Bugs will occur.

internal/domains/filesystem/directories.go

@@ -0,0 +1,53 @@
+package filesystem
+
+import (
+	"fmt"
+	"os"
+	"os/exec"
+	"time"
+
+	"github.com/sirupsen/logrus"
+)
+
+func (f *FS) prepareDirectories() error {
+	if _, err := os.Stat(f.sourceDir); os.IsNotExist(err) {
+		return fmt.Errorf("%w: %w (%w)", ErrFilesystem, ErrNoSource, err)
+	}
+
+	f.app.Logger().WithField("path", f.sourceDir).Info("Got source directory")
+
+	// Clean destination directory
+	if _, err := os.Stat(f.destinationDir); err == nil {
+		f.app.Logger().WithField("path", f.destinationDir).Info(
+			"Cleaning up the destination mountpoint",
+		)
+
+		// Try to unmount the destination FS if that was mounted before.
+		exec.Command("fusermount3", "-u", f.destinationDir).Run()
+		time.Sleep(5 * time.Second)
+
+		// Clean the destination
+		err := os.RemoveAll(f.destinationDir)
+		if err != nil {
+			return fmt.Errorf("%w: %w (%w)", ErrFilesystem, ErrFailedToCleanupDestination, err)
+		}
+	}
+
+	// Create the structure for the virtual filesystem.
+	for _, dir := range []string{f.destinationDir, f.cacheDir, f.metadataDir} {
+		if err := os.MkdirAll(dir, 0755); err != nil {
+			f.app.Logger().WithField("path", dir).Error("Operation on directory was unsuccessful")
+
+			return fmt.Errorf("%w: %w (%w)", ErrFilesystem, ErrFailedToCreateDestinationDirectory, err)
+		}
+	}
+
+	f.app.Logger().WithFields(logrus.Fields{
+		"source directory":         f.sourceDir,
+		"virtual filesystem mount": f.destinationDir,
+		"cache directory":          f.cacheDir,
+		"metadata directory":       f.metadataDir,
+	}).Debug("Filesystem directories prepared")
+
+	return nil
+}