From a6ec128cab3c77f7b3241aa9fd971fa19e5d6a3a Mon Sep 17 00:00:00 2001
From: Frederik Ring <frederik.ring@gmail.com>
Date: Thu, 1 Sep 2022 14:38:04 +0200
Subject: [PATCH] Run copying and pruning against multiple storages in parallel
 (#152)

---
 cmd/backup/script.go              | 32 +++++++++++++++++++++++--------
 cmd/backup/stats.go               |  2 ++
 internal/storage/webdav/webdav.go |  1 -
 3 files changed, 26 insertions(+), 9 deletions(-)

diff --git a/cmd/backup/script.go b/cmd/backup/script.go
index 8a33b60..b26fc05 100644
--- a/cmd/backup/script.go
+++ b/cmd/backup/script.go
@@ -32,6 +32,7 @@ import (
 	"github.com/otiai10/copy"
 	"github.com/sirupsen/logrus"
 	"golang.org/x/crypto/openpgp"
+	"golang.org/x/sync/errgroup"
 )
 
 // script holds all the stateful information required to orchestrate a
@@ -493,10 +494,15 @@ func (s *script) copyArchive() error {
 		}
 	}
 
+	eg := errgroup.Group{}
 	for _, backend := range s.storages {
-		if err := backend.Copy(s.file); err != nil {
-			return err
-		}
+		b := backend
+		eg.Go(func() error {
+			return b.Copy(s.file)
+		})
+	}
+	if err := eg.Wait(); err != nil {
+		return fmt.Errorf("copyArchive: error copying archive: %w", err)
 	}
 
 	return nil
@@ -512,16 +518,26 @@ func (s *script) pruneBackups() error {
 
 	deadline := time.Now().AddDate(0, 0, -int(s.c.BackupRetentionDays)).Add(s.c.BackupPruningLeeway)
 
+	eg := errgroup.Group{}
 	for _, backend := range s.storages {
-		if stats, err := backend.Prune(deadline, s.c.BackupPruningPrefix); err == nil {
-			s.stats.Storages[backend.Name()] = StorageStats{
+		b := backend
+		eg.Go(func() error {
+			stats, err := b.Prune(deadline, s.c.BackupPruningPrefix)
+			if err != nil {
+				return err
+			}
+			s.stats.Lock()
+			s.stats.Storages[b.Name()] = StorageStats{
 				Total:  stats.Total,
 				Pruned: stats.Pruned,
 			}
+			s.stats.Unlock()
+			return nil
+		})
+	}
 
-		} else {
-			return err
-		}
+	if err := eg.Wait(); err != nil {
+		return fmt.Errorf("pruneBackups: error pruning backups: %w", err)
 	}
 
 	return nil
diff --git a/cmd/backup/stats.go b/cmd/backup/stats.go
index fbb5e11..4eed0d9 100644
--- a/cmd/backup/stats.go
+++ b/cmd/backup/stats.go
@@ -5,6 +5,7 @@ package main
 
 import (
 	"bytes"
+	"sync"
 	"time"
 )
 
@@ -32,6 +33,7 @@ type StorageStats struct {
 
 // Stats global stats regarding script execution
 type Stats struct {
+	sync.Mutex
 	StartTime  time.Time
 	EndTime    time.Time
 	TookTime   time.Duration
diff --git a/internal/storage/webdav/webdav.go b/internal/storage/webdav/webdav.go
index 72b06d1..c95c164 100644
--- a/internal/storage/webdav/webdav.go
+++ b/internal/storage/webdav/webdav.go
@@ -35,7 +35,6 @@ type Config struct {
 
 // NewStorageBackend creates and initializes a new WebDav storage backend.
 func NewStorageBackend(opts Config, logFunc storage.Log) (storage.Backend, error) {
-
 	if opts.Username == "" || opts.Password == "" {
 		return nil, errors.New("NewStorageBackend: WEBDAV_URL is defined, but no credentials were provided")
 	} else {