Fix WebDAV spelling, remove some inconsistencies (#143)

* Simplify logging, fix WebDAV spelling

* Define options types per package

* Move util functions that are not used cross package

* Add per file license headers

* Rename config type

.dockerignore

@@ -1,19 +1,7 @@
-# Ignore everything
+test
-*
+.github
-
+.circleci
-# Exceptions:
+docs
-# Note: Wildcards for directories like * or ** don't work (yet) with exclamation marks!
+.editorconfig
-
+LICENSE
-!cmd/backup/*.go
+README.md
-!cmd/backup/*.tmpl
-
-!internal/storage/*.go
-!internal/storage/local/*.go
-!internal/storage/s3/*.go
-!internal/storage/ssh/*.go
-!internal/storage/webdav/*.go
-!internal/utilities/*.go
-
-!Dockerfile
-!entrypoint.sh
-!go.*

cmd/backup/lock.go

@@ -9,7 +9,6 @@ import (
 	"time"
 
 	"github.com/gofrs/flock"
-	"github.com/offen/docker-volume-backup/internal/utilities"
 )
 
 // lock opens a lockfile at the given location, keeping it locked until the
@@ -32,7 +31,7 @@ func (s *script) lock(lockfile string) (func() error, error) {
 	for {
 		acquired, err := fileLock.TryLock()
 		if err != nil {
-			return utilities.Noop, fmt.Errorf("lock: error trying lock: %w", err)
+			return noop, fmt.Errorf("lock: error trying lock: %w", err)
 		}
 		if acquired {
 			if s.encounteredLock {
@@ -53,7 +52,7 @@ func (s *script) lock(lockfile string) (func() error, error) {
 		case <-retry.C:
 			continue
 		case <-deadline.C:
-			return utilities.Noop, errors.New("lock: timed out waiting for lockfile to become available")
+			return noop, errors.New("lock: timed out waiting for lockfile to become available")
 		}
 	}
 }

cmd/backup/script.go

@@ -58,7 +58,7 @@ type script struct {
 // reading from env vars or other configuration sources is expected to happen
 // in this method.
 func newScript() (*script, error) {
-	stdOut, logBuffer := utilities.Buffer(os.Stdout)
+	stdOut, logBuffer := buffer(os.Stdout)
 	s := &script{
 		c: &Config{},
 		logger: &logrus.Logger{
@@ -72,7 +72,7 @@ func newScript() (*script, error) {
 			LogOutput: logBuffer,
 			Storages: map[string]StorageStats{
 				"S3":     {},
-				"WebDav": {},
+				"WebDAV": {},
 				"SSH":    {},
 				"Local":  {},
 			},
@@ -107,29 +107,31 @@ func newScript() (*script, error) {
 		s.cli = cli
 	}
 
-	logFunc := func(logType storage.LogType, context string, msg string, params ...interface{}) error {
+	logFunc := func(logType storage.LogLevel, context string, msg string, params ...interface{}) {
-		var allParams []interface{}
-		allParams = append(allParams, context)
-		allParams = append(allParams, params...)
-
 		switch logType {
-		case storage.INFO:
+		case storage.LogLevelWarning:
-			s.logger.Infof("[%s] "+msg, allParams...)
+			s.logger.Warnf("["+context+"] "+msg, params...)
-			return nil
+		case storage.LogLevelError:
-		case storage.WARNING:
+			s.logger.Errorf("["+context+"] "+msg, params...)
-			s.logger.Warnf("[%s] "+msg, allParams...)
+		case storage.LogLevelInfo:
-			return nil
-		case storage.ERROR:
-			return fmt.Errorf("[%s] "+msg, allParams...)
 		default:
-			s.logger.Warnf("[%s] "+msg, allParams...)
+			s.logger.Infof("["+context+"] "+msg, params...)
-			return nil
 		}
 	}
 
 	if s.c.AwsS3BucketName != "" {
-		if s3Backend, err := s3.NewStorageBackend(s.c.AwsEndpoint, s.c.AwsAccessKeyID, s.c.AwsSecretAccessKey, s.c.AwsIamRoleEndpoint,
+		s3Config := s3.Config{
-			s.c.AwsEndpointProto, s.c.AwsEndpointInsecure, s.c.AwsS3Path, s.c.AwsS3BucketName, s.c.AwsStorageClass, logFunc); err != nil {
+			Endpoint:         s.c.AwsEndpoint,
+			AccessKeyID:      s.c.AwsAccessKeyID,
+			SecretAccessKey:  s.c.AwsSecretAccessKey,
+			IamRoleEndpoint:  s.c.AwsIamRoleEndpoint,
+			EndpointProto:    s.c.AwsEndpointProto,
+			EndpointInsecure: s.c.AwsEndpointInsecure,
+			RemotePath:       s.c.AwsS3Path,
+			BucketName:       s.c.AwsS3BucketName,
+			StorageClass:     s.c.AwsStorageClass,
+		}
+		if s3Backend, err := s3.NewStorageBackend(s3Config, logFunc); err != nil {
 			return nil, err
 		} else {
 			s.storages = append(s.storages, s3Backend)
@@ -137,8 +139,14 @@ func newScript() (*script, error) {
 	}
 
 	if s.c.WebdavUrl != "" {
-		if webdavBackend, err := webdav.NewStorageBackend(s.c.WebdavUrl, s.c.WebdavPath, s.c.WebdavUsername, s.c.WebdavPassword,
+		webDavConfig := webdav.Config{
-			s.c.WebdavUrlInsecure, logFunc); err != nil {
+			URL:         s.c.WebdavUrl,
+			URLInsecure: s.c.WebdavUrlInsecure,
+			Username:    s.c.WebdavUsername,
+			Password:    s.c.WebdavPassword,
+			RemotePath:  s.c.WebdavPath,
+		}
+		if webdavBackend, err := webdav.NewStorageBackend(webDavConfig, logFunc); err != nil {
 			return nil, err
 		} else {
 			s.storages = append(s.storages, webdavBackend)
@@ -146,16 +154,30 @@ func newScript() (*script, error) {
 	}
 
 	if s.c.SSHHostName != "" {
-		if sshBackend, err := ssh.NewStorageBackend(s.c.SSHHostName, s.c.SSHPort, s.c.SSHUser, s.c.SSHPassword, s.c.SSHIdentityFile,
+		sshConfig := ssh.Config{
-			s.c.SSHIdentityPassphrase, s.c.SSHRemotePath, logFunc); err != nil {
+			HostName:           s.c.SSHHostName,
+			Port:               s.c.SSHPort,
+			User:               s.c.SSHUser,
+			Password:           s.c.SSHPassword,
+			IdentityFile:       s.c.SSHIdentityFile,
+			IdentityPassphrase: s.c.SSHIdentityPassphrase,
+			RemotePath:         s.c.SSHRemotePath,
+		}
+		if sshBackend, err := ssh.NewStorageBackend(sshConfig, logFunc); err != nil {
 			return nil, err
 		} else {
 			s.storages = append(s.storages, sshBackend)
 		}
 	}
 
-	localBackend := local.NewStorageBackend(s.c.BackupArchive, s.c.BackupLatestSymlink, logFunc)
+	if _, err := os.Stat(s.c.BackupArchive); !os.IsNotExist(err) {
-	s.storages = append(s.storages, localBackend)
+		localConfig := local.Config{
+			ArchivePath:   s.c.BackupArchive,
+			LatestSymlink: s.c.BackupLatestSymlink,
+		}
+		localBackend := local.NewStorageBackend(localConfig, logFunc)
+		s.storages = append(s.storages, localBackend)
+	}
 
 	if s.c.EmailNotificationRecipient != "" {
 		emailURL := fmt.Sprintf(
@@ -228,14 +250,14 @@ func newScript() (*script, error) {
 // restart everything that has been stopped.
 func (s *script) stopContainers() (func() error, error) {
 	if s.cli == nil {
-		return utilities.Noop, nil
+		return noop, nil
 	}
 
 	allContainers, err := s.cli.ContainerList(context.Background(), types.ContainerListOptions{
 		Quiet: true,
 	})
 	if err != nil {
-		return utilities.Noop, fmt.Errorf("stopContainersAndRun: error querying for containers: %w", err)
+		return noop, fmt.Errorf("stopContainersAndRun: error querying for containers: %w", err)
 	}
 
 	containerLabel := fmt.Sprintf(
@@ -251,11 +273,11 @@ func (s *script) stopContainers() (func() error, error) {
 	})
 
 	if err != nil {
-		return utilities.Noop, fmt.Errorf("stopContainersAndRun: error querying for containers to stop: %w", err)
+		return noop, fmt.Errorf("stopContainersAndRun: error querying for containers to stop: %w", err)
 	}
 
 	if len(containersToStop) == 0 {
-		return utilities.Noop, nil
+		return noop, nil
 	}
 
 	s.logger.Infof(
@@ -357,7 +379,7 @@ func (s *script) createArchive() error {
 		backupSources = filepath.Join("/tmp", s.c.BackupSources)
 		// copy before compressing guard against a situation where backup folder's content are still growing.
 		s.registerHook(hookLevelPlumbing, func(error) error {
-			if err := utilities.Remove(backupSources); err != nil {
+			if err := remove(backupSources); err != nil {
 				return fmt.Errorf("takeBackup: error removing snapshot: %w", err)
 			}
 			s.logger.Infof("Removed snapshot `%s`.", backupSources)
@@ -367,15 +389,15 @@ func (s *script) createArchive() error {
 			PreserveTimes: true,
 			PreserveOwner: true,
 		}); err != nil {
-			return fmt.Errorf("takeBackup: error creating snapshot: %w", err)
+			return fmt.Errorf("createArchive: error creating snapshot: %w", err)
 		}
 		s.logger.Infof("Created snapshot of `%s` at `%s`.", s.c.BackupSources, backupSources)
 	}
 
 	tarFile := s.file
 	s.registerHook(hookLevelPlumbing, func(error) error {
-		if err := utilities.Remove(tarFile); err != nil {
+		if err := remove(tarFile); err != nil {
-			return fmt.Errorf("takeBackup: error removing tar file: %w", err)
+			return fmt.Errorf("createArchive: error removing tar file: %w", err)
 		}
 		s.logger.Infof("Removed tar file `%s`.", tarFile)
 		return nil
@@ -383,7 +405,7 @@ func (s *script) createArchive() error {
 
 	backupPath, err := filepath.Abs(stripTrailingSlashes(backupSources))
 	if err != nil {
-		return fmt.Errorf("takeBackup: error getting absolute path: %w", err)
+		return fmt.Errorf("createArchive: error getting absolute path: %w", err)
 	}
 
 	var filesEligibleForBackup []string
@@ -398,11 +420,11 @@ func (s *script) createArchive() error {
 		filesEligibleForBackup = append(filesEligibleForBackup, path)
 		return nil
 	}); err != nil {
-		return fmt.Errorf("compress: error walking filesystem tree: %w", err)
+		return fmt.Errorf("createArchive: error walking filesystem tree: %w", err)
 	}
 
 	if err := createArchive(filesEligibleForBackup, backupSources, tarFile); err != nil {
-		return fmt.Errorf("takeBackup: error compressing backup folder: %w", err)
+		return fmt.Errorf("createArchive: error compressing backup folder: %w", err)
 	}
 
 	s.logger.Infof("Created backup of `%s` at `%s`.", backupSources, tarFile)
@@ -419,8 +441,8 @@ func (s *script) encryptArchive() error {
 
 	gpgFile := fmt.Sprintf("%s.gpg", s.file)
 	s.registerHook(hookLevelPlumbing, func(error) error {
-		if err := utilities.Remove(gpgFile); err != nil {
+		if err := remove(gpgFile); err != nil {
-			return fmt.Errorf("encryptBackup: error removing gpg file: %w", err)
+			return fmt.Errorf("encryptArchive: error removing gpg file: %w", err)
 		}
 		s.logger.Infof("Removed GPG file `%s`.", gpgFile)
 		return nil
@@ -428,7 +450,7 @@ func (s *script) encryptArchive() error {
 
 	outFile, err := os.Create(gpgFile)
 	if err != nil {
-		return fmt.Errorf("encryptBackup: error opening out file: %w", err)
+		return fmt.Errorf("encryptArchive: error opening out file: %w", err)
 	}
 	defer outFile.Close()
 
@@ -438,17 +460,17 @@ func (s *script) encryptArchive() error {
 		FileName: name,
 	}, nil)
 	if err != nil {
-		return fmt.Errorf("encryptBackup: error encrypting backup file: %w", err)
+		return fmt.Errorf("encryptArchive: error encrypting backup file: %w", err)
 	}
 	defer dst.Close()
 
 	src, err := os.Open(s.file)
 	if err != nil {
-		return fmt.Errorf("encryptBackup: error opening backup file `%s`: %w", s.file, err)
+		return fmt.Errorf("encryptArchive: error opening backup file `%s`: %w", s.file, err)
 	}
 
 	if _, err := io.Copy(dst, src); err != nil {
-		return fmt.Errorf("encryptBackup: error writing ciphertext to file: %w", err)
+		return fmt.Errorf("encryptArchive: error writing ciphertext to file: %w", err)
 	}
 
 	s.file = gpgFile
@@ -461,7 +483,7 @@ func (s *script) encryptArchive() error {
 func (s *script) copyArchive() error {
 	_, name := path.Split(s.file)
 	if stat, err := os.Stat(s.file); err != nil {
-		return fmt.Errorf("copyBackup: unable to stat backup file: %w", err)
+		return fmt.Errorf("copyArchive: unable to stat backup file: %w", err)
 	} else {
 		size := stat.Size()
 		s.stats.BackupFile = BackupFileStats{

cmd/backup/util.go

@@ -0,0 +1,52 @@
+// Copyright 2022 - Offen Authors <hioffen@posteo.de>
+// SPDX-License-Identifier: MPL-2.0
+
+package main
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"os"
+)
+
+var noop = func() error { return nil }
+
+// remove removes the given file or directory from disk.
+func remove(location string) error {
+	fi, err := os.Lstat(location)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return nil
+		}
+		return fmt.Errorf("remove: error checking for existence of `%s`: %w", location, err)
+	}
+	if fi.IsDir() {
+		err = os.RemoveAll(location)
+	} else {
+		err = os.Remove(location)
+	}
+	if err != nil {
+		return fmt.Errorf("remove: error removing `%s`: %w", location, err)
+	}
+	return nil
+}
+
+// buffer takes an io.Writer and returns a wrapped version of the
+// writer that writes to both the original target as well as the returned buffer
+func buffer(w io.Writer) (io.Writer, *bytes.Buffer) {
+	buffering := &bufferingWriter{buf: bytes.Buffer{}, writer: w}
+	return buffering, &buffering.buf
+}
+
+type bufferingWriter struct {
+	buf    bytes.Buffer
+	writer io.Writer
+}
+
+func (b *bufferingWriter) Write(p []byte) (n int, err error) {
+	if n, err := b.buf.Write(p); err != nil {
+		return n, fmt.Errorf("(*bufferingWriter).Write: error writing to buffer: %w", err)
+	}
+	return b.writer.Write(p)
+}

internal/storage/local/local.go

@@ -1,7 +1,11 @@
+// Copyright 2022 - Offen Authors <hioffen@posteo.de>
+// SPDX-License-Identifier: MPL-2.0
+
 package local
 
 import (
 	"fmt"
+	"io"
 	"os"
 	"path"
 	"path/filepath"
@@ -16,14 +20,20 @@ type localStorage struct {
 	latestSymlink string
 }
 
+// Config allows configuration of a local storage backend.
+type Config struct {
+	ArchivePath   string
+	LatestSymlink string
+}
+
 // NewStorageBackend creates and initializes a new local storage backend.
-func NewStorageBackend(archivePath string, latestSymlink string, logFunc storage.Log) storage.Backend {
+func NewStorageBackend(opts Config, logFunc storage.Log) storage.Backend {
 	return &localStorage{
 		StorageBackend: &storage.StorageBackend{
-			DestinationPath: archivePath,
+			DestinationPath: opts.ArchivePath,
 			Log:             logFunc,
 		},
-		latestSymlink: latestSymlink,
+		latestSymlink: opts.LatestSymlink,
 	}
 }
 
@@ -34,16 +44,12 @@ func (b *localStorage) Name() string {
 
 // Copy copies the given file to the local storage backend.
 func (b *localStorage) Copy(file string) error {
-	if _, err := os.Stat(b.DestinationPath); os.IsNotExist(err) {
-		return nil
-	}
-
 	_, name := path.Split(file)
 
-	if err := utilities.CopyFile(file, path.Join(b.DestinationPath, name)); err != nil {
+	if err := copyFile(file, path.Join(b.DestinationPath, name)); err != nil {
-		return b.Log(storage.ERROR, b.Name(), "Copy: Error copying file to local archive! %w", err)
+		return fmt.Errorf("(*localStorage).Copy: Error copying file to local archive! %w", err)
 	}
-	b.Log(storage.INFO, b.Name(), "Stored copy of backup `%s` in local archive `%s`.", file, b.DestinationPath)
+	b.Log(storage.LogLevelInfo, b.Name(), "Stored copy of backup `%s` in local archive `%s`.", file, b.DestinationPath)
 
 	if b.latestSymlink != "" {
 		symlink := path.Join(b.DestinationPath, b.latestSymlink)
@@ -51,9 +57,9 @@ func (b *localStorage) Copy(file string) error {
 			os.Remove(symlink)
 		}
 		if err := os.Symlink(name, symlink); err != nil {
-			return b.Log(storage.ERROR, b.Name(), "Copy: error creating latest symlink! %w", err)
+			return fmt.Errorf("(*localStorage).Copy: error creating latest symlink! %w", err)
 		}
-		b.Log(storage.INFO, b.Name(), "Created/Updated symlink `%s` for latest backup.", b.latestSymlink)
+		b.Log(storage.LogLevelInfo, b.Name(), "Created/Updated symlink `%s` for latest backup.", b.latestSymlink)
 	}
 
 	return nil
@@ -67,8 +73,8 @@ func (b *localStorage) Prune(deadline time.Time, pruningPrefix string) (*storage
 	)
 	globMatches, err := filepath.Glob(globPattern)
 	if err != nil {
-		return nil, b.Log(storage.ERROR, b.Name(),
+		return nil, fmt.Errorf(
-			"Prune: Error looking up matching files using pattern %s! %w",
+			"(*localStorage).Prune: Error looking up matching files using pattern %s: %w",
 			globPattern,
 			err,
 		)
@@ -78,8 +84,8 @@ func (b *localStorage) Prune(deadline time.Time, pruningPrefix string) (*storage
 	for _, candidate := range globMatches {
 		fi, err := os.Lstat(candidate)
 		if err != nil {
-			return nil, b.Log(storage.ERROR, b.Name(),
+			return nil, fmt.Errorf(
-				"Prune: Error calling Lstat on file %s! %w",
+				"(*localStorage).Prune: Error calling Lstat on file %s: %w",
 				candidate,
 				err,
 			)
@@ -94,8 +100,8 @@ func (b *localStorage) Prune(deadline time.Time, pruningPrefix string) (*storage
 	for _, candidate := range candidates {
 		fi, err := os.Stat(candidate)
 		if err != nil {
-			return nil, b.Log(storage.ERROR, b.Name(),
+			return nil, fmt.Errorf(
-				"Prune: Error calling stat on file %s! %w",
+				"(*localStorage).Prune: Error calling stat on file %s! %w",
 				candidate,
 				err,
 			)
@@ -110,7 +116,7 @@ func (b *localStorage) Prune(deadline time.Time, pruningPrefix string) (*storage
 		Pruned: uint(len(matches)),
 	}
 
-	b.DoPrune(b.Name(), len(matches), len(candidates), "local backup(s)", func() error {
+	if err := b.DoPrune(b.Name(), len(matches), len(candidates), "local backup(s)", func() error {
 		var removeErrors []error
 		for _, match := range matches {
 			if err := os.Remove(match); err != nil {
@@ -118,14 +124,37 @@ func (b *localStorage) Prune(deadline time.Time, pruningPrefix string) (*storage
 			}
 		}
 		if len(removeErrors) != 0 {
-			return b.Log(storage.ERROR, b.Name(),
+			return fmt.Errorf(
-				"Prune: %d error(s) deleting local files, starting with: %w",
+				"(*localStorage).Prune: %d error(s) deleting local files, starting with: %w",
 				len(removeErrors),
 				utilities.Join(removeErrors...),
 			)
 		}
 		return nil
-	})
+	}); err != nil {
+		return stats, err
+	}
 
 	return stats, nil
 }
+
+// copy creates a copy of the file located at `dst` at `src`.
+func copyFile(src, dst string) error {
+	in, err := os.Open(src)
+	if err != nil {
+		return err
+	}
+	defer in.Close()
+
+	out, err := os.Create(dst)
+	if err != nil {
+		return err
+	}
+
+	_, err = io.Copy(out, in)
+	if err != nil {
+		out.Close()
+		return err
+	}
+	return out.Close()
+}

internal/storage/s3/s3.go

@@ -1,8 +1,12 @@
+// Copyright 2022 - Offen Authors <hioffen@posteo.de>
+// SPDX-License-Identifier: MPL-2.0
+
 package s3
 
 import (
 	"context"
 	"errors"
+	"fmt"
 	"path"
 	"path/filepath"
 	"time"
@@ -20,54 +24,66 @@ type s3Storage struct {
 	storageClass string
 }
 
+// Config contains values that define the configuration of a S3 backend.
+type Config struct {
+	Endpoint         string
+	AccessKeyID      string
+	SecretAccessKey  string
+	IamRoleEndpoint  string
+	EndpointProto    string
+	EndpointInsecure bool
+	RemotePath       string
+	BucketName       string
+	StorageClass     string
+}
+
 // NewStorageBackend creates and initializes a new S3/Minio storage backend.
-func NewStorageBackend(endpoint string, accessKeyId string, secretAccessKey string, iamRoleEndpoint string, endpointProto string, endpointInsecure bool,
+func NewStorageBackend(opts Config, logFunc storage.Log) (storage.Backend, error) {
-	remotePath string, bucket string, storageClass string, logFunc storage.Log) (storage.Backend, error) {
 
 	var creds *credentials.Credentials
-	if accessKeyId != "" && secretAccessKey != "" {
+	if opts.AccessKeyID != "" && opts.SecretAccessKey != "" {
 		creds = credentials.NewStaticV4(
-			accessKeyId,
+			opts.AccessKeyID,
-			secretAccessKey,
+			opts.SecretAccessKey,
 			"",
 		)
-	} else if iamRoleEndpoint != "" {
+	} else if opts.IamRoleEndpoint != "" {
-		creds = credentials.NewIAM(iamRoleEndpoint)
+		creds = credentials.NewIAM(opts.IamRoleEndpoint)
 	} else {
-		return nil, errors.New("newScript: AWS_S3_BUCKET_NAME is defined, but no credentials were provided")
+		return nil, errors.New("NewStorageBackend: AWS_S3_BUCKET_NAME is defined, but no credentials were provided")
 	}
 
 	options := minio.Options{
 		Creds:  creds,
-		Secure: endpointProto == "https",
+		Secure: opts.EndpointProto == "https",
 	}
 
-	if endpointInsecure {
+	if opts.EndpointInsecure {
 		if !options.Secure {
-			return nil, errors.New("newScript: AWS_ENDPOINT_INSECURE = true is only meaningful for https")
+			return nil, errors.New("NewStorageBackend: AWS_ENDPOINT_INSECURE = true is only meaningful for https")
 		}
 
 		transport, err := minio.DefaultTransport(true)
 		if err != nil {
-			return nil, logFunc(storage.ERROR, "S3", "NewScript: failed to create default minio transport")
+			return nil, fmt.Errorf("NewStorageBackend: failed to create default minio transport")
 		}
 		transport.TLSClientConfig.InsecureSkipVerify = true
 		options.Transport = transport
 	}
 
-	mc, err := minio.New(endpoint, &options)
+	mc, err := minio.New(opts.Endpoint, &options)
 	if err != nil {
-		return nil, logFunc(storage.ERROR, "S3", "NewScript: error setting up minio client: %w", err)
+		return nil, fmt.Errorf("NewStorageBackend: error setting up minio client: %w", err)
 	}
 
 	return &s3Storage{
 		StorageBackend: &storage.StorageBackend{
-			DestinationPath: remotePath,
+			DestinationPath: opts.RemotePath,
 			Log:             logFunc,
 		},
 		client:       mc,
-		bucket:       bucket,
+		bucket:       opts.BucketName,
-		storageClass: storageClass,
+		storageClass: opts.StorageClass,
 	}, nil
 }
 
@@ -85,9 +101,9 @@ func (b *s3Storage) Copy(file string) error {
 		StorageClass: b.storageClass,
 	}); err != nil {
 		errResp := minio.ToErrorResponse(err)
-		return b.Log(storage.ERROR, b.Name(), "Copy: error uploading backup to remote storage: [Message]: '%s', [Code]: %s, [StatusCode]: %d", errResp.Message, errResp.Code, errResp.StatusCode)
+		return fmt.Errorf("(*s3Storage).Copy: error uploading backup to remote storage: [Message]: '%s', [Code]: %s, [StatusCode]: %d", errResp.Message, errResp.Code, errResp.StatusCode)
 	}
-	b.Log(storage.INFO, b.Name(), "Uploaded a copy of backup `%s` to bucket `%s`.", file, b.bucket)
+	b.Log(storage.LogLevelInfo, b.Name(), "Uploaded a copy of backup `%s` to bucket `%s`.", file, b.bucket)
 
 	return nil
 }
@@ -105,8 +121,8 @@ func (b *s3Storage) Prune(deadline time.Time, pruningPrefix string) (*storage.Pr
 	for candidate := range candidates {
 		lenCandidates++
 		if candidate.Err != nil {
-			return nil, b.Log(storage.ERROR, b.Name(),
+			return nil, fmt.Errorf(
-				"Prune: Error looking up candidates from remote storage! %w",
+				"(*s3Storage).Prune: Error looking up candidates from remote storage! %w",
 				candidate.Err,
 			)
 		}
@@ -120,7 +136,7 @@ func (b *s3Storage) Prune(deadline time.Time, pruningPrefix string) (*storage.Pr
 		Pruned: uint(len(matches)),
 	}
 
-	b.DoPrune(b.Name(), len(matches), lenCandidates, "remote backup(s)", func() error {
+	if err := b.DoPrune(b.Name(), len(matches), lenCandidates, "remote backup(s)", func() error {
 		objectsCh := make(chan minio.ObjectInfo)
 		go func() {
 			for _, match := range matches {
@@ -139,7 +155,9 @@ func (b *s3Storage) Prune(deadline time.Time, pruningPrefix string) (*storage.Pr
 			return utilities.Join(removeErrors...)
 		}
 		return nil
-	})
+	}); err != nil {
+		return stats, err
+	}
 
 	return stats, nil
 }

internal/storage/ssh/ssh.go

@@ -1,3 +1,6 @@
+// Copyright 2022 - Offen Authors <hioffen@posteo.de>
+// SPDX-License-Identifier: MPL-2.0
+
 package ssh
 
 import (
@@ -23,47 +26,56 @@ type sshStorage struct {
 	hostName   string
 }
 
-// NewStorageBackend creates and initializes a new SSH storage backend.
+// Config allows to configure a SSH backend.
-func NewStorageBackend(hostName string, port string, user string, password string, identityFile string, identityPassphrase string, remotePath string,
+type Config struct {
-	logFunc storage.Log) (storage.Backend, error) {
+	HostName           string
+	Port               string
+	User               string
+	Password           string
+	IdentityFile       string
+	IdentityPassphrase string
+	RemotePath         string
+}
 
+// NewStorageBackend creates and initializes a new SSH storage backend.
+func NewStorageBackend(opts Config, logFunc storage.Log) (storage.Backend, error) {
 	var authMethods []ssh.AuthMethod
 
-	if password != "" {
+	if opts.Password != "" {
-		authMethods = append(authMethods, ssh.Password(password))
+		authMethods = append(authMethods, ssh.Password(opts.Password))
 	}
 
-	if _, err := os.Stat(identityFile); err == nil {
+	if _, err := os.Stat(opts.IdentityFile); err == nil {
-		key, err := ioutil.ReadFile(identityFile)
+		key, err := ioutil.ReadFile(opts.IdentityFile)
 		if err != nil {
-			return nil, errors.New("newScript: error reading the private key")
+			return nil, errors.New("NewStorageBackend: error reading the private key")
 		}
 
 		var signer ssh.Signer
-		if identityPassphrase != "" {
+		if opts.IdentityPassphrase != "" {
-			signer, err = ssh.ParsePrivateKeyWithPassphrase(key, []byte(identityPassphrase))
+			signer, err = ssh.ParsePrivateKeyWithPassphrase(key, []byte(opts.IdentityPassphrase))
 			if err != nil {
-				return nil, errors.New("newScript: error parsing the encrypted private key")
+				return nil, errors.New("NewStorageBackend: error parsing the encrypted private key")
 			}
 			authMethods = append(authMethods, ssh.PublicKeys(signer))
 		} else {
 			signer, err = ssh.ParsePrivateKey(key)
 			if err != nil {
-				return nil, errors.New("newScript: error parsing the private key")
+				return nil, errors.New("NewStorageBackend: error parsing the private key")
 			}
 			authMethods = append(authMethods, ssh.PublicKeys(signer))
 		}
 	}
 
 	sshClientConfig := &ssh.ClientConfig{
-		User:            user,
+		User:            opts.User,
 		Auth:            authMethods,
 		HostKeyCallback: ssh.InsecureIgnoreHostKey(),
 	}
-	sshClient, err := ssh.Dial("tcp", fmt.Sprintf("%s:%s", hostName, port), sshClientConfig)
+	sshClient, err := ssh.Dial("tcp", fmt.Sprintf("%s:%s", opts.HostName, opts.Port), sshClientConfig)
 
 	if err != nil {
-		return nil, logFunc(storage.ERROR, "SSH", "NewScript: Error creating ssh client! %w", err)
+		return nil, fmt.Errorf("NewStorageBackend: Error creating ssh client: %w", err)
 	}
 	_, _, err = sshClient.SendRequest("keepalive", false, nil)
 	if err != nil {
@@ -72,17 +84,17 @@ func NewStorageBackend(hostName string, port string, user string, password strin
 
 	sftpClient, err := sftp.NewClient(sshClient)
 	if err != nil {
-		return nil, logFunc(storage.ERROR, "SSH", "NewScript: error creating sftp client! %w", err)
+		return nil, fmt.Errorf("NewStorageBackend: error creating sftp client: %w", err)
 	}
 
 	return &sshStorage{
 		StorageBackend: &storage.StorageBackend{
-			DestinationPath: remotePath,
+			DestinationPath: opts.RemotePath,
 			Log:             logFunc,
 		},
 		client:     sshClient,
 		sftpClient: sftpClient,
-		hostName:   hostName,
+		hostName:   opts.HostName,
 	}, nil
 }
 
@@ -96,13 +108,13 @@ func (b *sshStorage) Copy(file string) error {
 	source, err := os.Open(file)
 	_, name := path.Split(file)
 	if err != nil {
-		return b.Log(storage.ERROR, b.Name(), "Copy: Error reading the file to be uploaded! %w", err)
+		return fmt.Errorf("(*sshStorage).Copy: Error reading the file to be uploaded! %w", err)
 	}
 	defer source.Close()
 
 	destination, err := b.sftpClient.Create(filepath.Join(b.DestinationPath, name))
 	if err != nil {
-		return b.Log(storage.ERROR, b.Name(), "Copy: Error creating file on SSH storage! %w", err)
+		return fmt.Errorf("(*sshStorage).Copy: Error creating file on SSH storage! %w", err)
 	}
 	defer destination.Close()
 
@@ -112,31 +124,31 @@ func (b *sshStorage) Copy(file string) error {
 		if err == io.EOF {
 			tot, err := destination.Write(chunk[:num])
 			if err != nil {
-				return b.Log(storage.ERROR, b.Name(), "Copy: Error uploading the file to SSH storage! %w", err)
+				return fmt.Errorf("(*sshStorage).Copy: Error uploading the file to SSH storage! %w", err)
 			}
 
 			if tot != len(chunk[:num]) {
-				return b.Log(storage.ERROR, b.Name(), "sshClient: failed to write stream")
+				return errors.New("(*sshStorage).Copy: failed to write stream")
 			}
 
 			break
 		}
 
 		if err != nil {
-			return b.Log(storage.ERROR, b.Name(), "Copy: Error uploading the file to SSH storage! %w", err)
+			return fmt.Errorf("(*sshStorage).Copy: Error uploading the file to SSH storage! %w", err)
 		}
 
 		tot, err := destination.Write(chunk[:num])
 		if err != nil {
-			return b.Log(storage.ERROR, b.Name(), "Copy: Error uploading the file to SSH storage! %w", err)
+			return fmt.Errorf("(*sshStorage).Copy: Error uploading the file to SSH storage! %w", err)
 		}
 
 		if tot != len(chunk[:num]) {
-			return b.Log(storage.ERROR, b.Name(), "sshClient: failed to write stream")
+			return fmt.Errorf("(*sshStorage).Copy: failed to write stream")
 		}
 	}
 
-	b.Log(storage.INFO, b.Name(), "Uploaded a copy of backup `%s` to SSH storage '%s' at path '%s'.", file, b.hostName, b.DestinationPath)
+	b.Log(storage.LogLevelInfo, b.Name(), "Uploaded a copy of backup `%s` to SSH storage '%s' at path '%s'.", file, b.hostName, b.DestinationPath)
 
 	return nil
 }
@@ -145,7 +157,7 @@ func (b *sshStorage) Copy(file string) error {
 func (b *sshStorage) Prune(deadline time.Time, pruningPrefix string) (*storage.PruneStats, error) {
 	candidates, err := b.sftpClient.ReadDir(b.DestinationPath)
 	if err != nil {
-		return nil, b.Log(storage.ERROR, b.Name(), "Prune: Error reading directory from SSH storage! %w", err)
+		return nil, fmt.Errorf("(*sshStorage).Prune: Error reading directory from SSH storage! %w", err)
 	}
 
 	var matches []string
@@ -163,14 +175,16 @@ func (b *sshStorage) Prune(deadline time.Time, pruningPrefix string) (*storage.P
 		Pruned: uint(len(matches)),
 	}
 
-	b.DoPrune(b.Name(), len(matches), len(candidates), "SSH backup(s)", func() error {
+	if err := b.DoPrune(b.Name(), len(matches), len(candidates), "SSH backup(s)", func() error {
 		for _, match := range matches {
 			if err := b.sftpClient.Remove(filepath.Join(b.DestinationPath, match)); err != nil {
-				return b.Log(storage.ERROR, b.Name(), "Prune: Error removing file from SSH storage! %w", err)
+				return fmt.Errorf("(*sshStorage).Prune: Error removing file from SSH storage! %w", err)
 			}
 		}
 		return nil
-	})
+	}); err != nil {
+		return stats, err
+	}
 
 	return stats, nil
 }

internal/storage/storage.go

@@ -1,3 +1,6 @@
+// Copyright 2022 - Offen Authors <hioffen@posteo.de>
+// SPDX-License-Identifier: MPL-2.0
+
 package storage
 
 import (
@@ -18,15 +21,15 @@ type StorageBackend struct {
 	Log             Log
 }
 
-type LogType string
+type LogLevel int
 
 const (
-	INFO    LogType = "INFO"
+	LogLevelInfo LogLevel = iota
-	WARNING LogType = "WARNING"
+	LogLevelWarning
-	ERROR   LogType = "ERROR"
+	LogLevelError
 )
 
-type Log func(logType LogType, context string, msg string, params ...interface{}) error
+type Log func(logType LogLevel, context string, msg string, params ...interface{})
 
 // PruneStats is a wrapper struct for returning stats after pruning
 type PruneStats struct {
@@ -41,7 +44,7 @@ func (b *StorageBackend) DoPrune(context string, lenMatches, lenCandidates int,
 		if err := doRemoveFiles(); err != nil {
 			return err
 		}
-		b.Log(INFO, context,
+		b.Log(LogLevelInfo, context,
 			"Pruned %d out of %d %s as their age exceeded the configured retention period of %d days.",
 			lenMatches,
 			lenCandidates,
@@ -49,10 +52,10 @@ func (b *StorageBackend) DoPrune(context string, lenMatches, lenCandidates int,
 			b.RetentionDays,
 		)
 	} else if lenMatches != 0 && lenMatches == lenCandidates {
-		b.Log(WARNING, context, "The current configuration would delete all %d existing %s.", lenMatches, description)
+		b.Log(LogLevelWarning, context, "The current configuration would delete all %d existing %s.", lenMatches, description)
-		b.Log(WARNING, context, "Refusing to do so, please check your configuration.")
+		b.Log(LogLevelWarning, context, "Refusing to do so, please check your configuration.")
 	} else {
-		b.Log(INFO, context, "None of %d existing %s were pruned.", lenCandidates, description)
+		b.Log(LogLevelInfo, context, "None of %d existing %s were pruned.", lenCandidates, description)
 	}
 	return nil
 }

internal/storage/webdav/webdav.go

@@ -1,7 +1,11 @@
+// Copyright 2022 - Offen Authors <hioffen@posteo.de>
+// SPDX-License-Identifier: MPL-2.0
+
 package webdav
 
 import (
 	"errors"
+	"fmt"
 	"io/fs"
 	"net/http"
 	"os"
@@ -20,28 +24,36 @@ type webDavStorage struct {
 	url    string
 }
 
+// Config allows to configure a WebDAV storage backend.
+type Config struct {
+	URL         string
+	RemotePath  string
+	Username    string
+	Password    string
+	URLInsecure bool
+}
+
 // NewStorageBackend creates and initializes a new WebDav storage backend.
-func NewStorageBackend(url string, remotePath string, username string, password string, urlInsecure bool,
+func NewStorageBackend(opts Config, logFunc storage.Log) (storage.Backend, error) {
-	logFunc storage.Log) (storage.Backend, error) {
 
-	if username == "" || password == "" {
+	if opts.Username == "" || opts.Password == "" {
-		return nil, errors.New("newScript: WEBDAV_URL is defined, but no credentials were provided")
+		return nil, errors.New("NewStorageBackend: WEBDAV_URL is defined, but no credentials were provided")
 	} else {
-		webdavClient := gowebdav.NewClient(url, username, password)
+		webdavClient := gowebdav.NewClient(opts.URL, opts.Username, opts.Password)
 
-		if urlInsecure {
+		if opts.URLInsecure {
 			defaultTransport, ok := http.DefaultTransport.(*http.Transport)
 			if !ok {
-				return nil, errors.New("newScript: unexpected error when asserting type for http.DefaultTransport")
+				return nil, errors.New("NewStorageBackend: unexpected error when asserting type for http.DefaultTransport")
 			}
 			webdavTransport := defaultTransport.Clone()
-			webdavTransport.TLSClientConfig.InsecureSkipVerify = urlInsecure
+			webdavTransport.TLSClientConfig.InsecureSkipVerify = opts.URLInsecure
 			webdavClient.SetTransport(webdavTransport)
 		}
 
 		return &webDavStorage{
 			StorageBackend: &storage.StorageBackend{
-				DestinationPath: remotePath,
+				DestinationPath: opts.RemotePath,
 				Log:             logFunc,
 			},
 			client: webdavClient,
@@ -51,7 +63,7 @@ func NewStorageBackend(url string, remotePath string, username string, password
 
 // Name returns the name of the storage backend
 func (b *webDavStorage) Name() string {
-	return "WebDav"
+	return "WebDAV"
 }
 
 // Copy copies the given file to the WebDav storage backend.
@@ -59,15 +71,15 @@ func (b *webDavStorage) Copy(file string) error {
 	bytes, err := os.ReadFile(file)
 	_, name := path.Split(file)
 	if err != nil {
-		return b.Log(storage.ERROR, b.Name(), "Copy: Error reading the file to be uploaded! %w", err)
+		return fmt.Errorf("(*webDavStorage).Copy: Error reading the file to be uploaded! %w", err)
 	}
 	if err := b.client.MkdirAll(b.DestinationPath, 0644); err != nil {
-		return b.Log(storage.ERROR, b.Name(), "Copy: Error creating directory '%s' on WebDAV server! %w", b.DestinationPath, err)
+		return fmt.Errorf("(*webDavStorage).Copy: Error creating directory '%s' on WebDAV server! %w", b.DestinationPath, err)
 	}
 	if err := b.client.Write(filepath.Join(b.DestinationPath, name), bytes, 0644); err != nil {
-		return b.Log(storage.ERROR, b.Name(), "Copy: Error uploading the file to WebDAV server! %w", err)
+		return fmt.Errorf("(*webDavStorage).Copy: Error uploading the file to WebDAV server! %w", err)
 	}
-	b.Log(storage.INFO, b.Name(), "Uploaded a copy of backup `%s` to WebDAV-URL '%s' at path '%s'.", file, b.url, b.DestinationPath)
+	b.Log(storage.LogLevelInfo, b.Name(), "Uploaded a copy of backup `%s` to WebDAV-URL '%s' at path '%s'.", file, b.url, b.DestinationPath)
 
 	return nil
 }
@@ -76,7 +88,7 @@ func (b *webDavStorage) Copy(file string) error {
 func (b *webDavStorage) Prune(deadline time.Time, pruningPrefix string) (*storage.PruneStats, error) {
 	candidates, err := b.client.ReadDir(b.DestinationPath)
 	if err != nil {
-		return nil, b.Log(storage.ERROR, b.Name(), "Prune: Error looking up candidates from remote storage! %w", err)
+		return nil, fmt.Errorf("(*webDavStorage).Prune: Error looking up candidates from remote storage! %w", err)
 	}
 	var matches []fs.FileInfo
 	var lenCandidates int
@@ -95,14 +107,16 @@ func (b *webDavStorage) Prune(deadline time.Time, pruningPrefix string) (*storag
 		Pruned: uint(len(matches)),
 	}
 
-	b.DoPrune(b.Name(), len(matches), lenCandidates, "WebDAV backup(s)", func() error {
+	if err := b.DoPrune(b.Name(), len(matches), lenCandidates, "WebDAV backup(s)", func() error {
 		for _, match := range matches {
 			if err := b.client.Remove(filepath.Join(b.DestinationPath, match.Name())); err != nil {
-				return b.Log(storage.ERROR, b.Name(), "Prune: Error removing file from WebDAV storage! %w", err)
+				return fmt.Errorf("(*webDavStorage).Prune: Error removing file from WebDAV storage! %w", err)
 			}
 		}
 		return nil
-	})
+	}); err != nil {
+		return stats, err
+	}
 
 	return stats, nil
 }

internal/utilities/util.go

@@ -4,38 +4,11 @@
 package utilities
 
 import (
-	"bytes"
 	"errors"
-	"fmt"
-	"io"
-	"os"
 	"strings"
 )
 
-var Noop = func() error { return nil }
+// Join takes a list of errors and joins them into a single error
-
-// copy creates a copy of the file located at `dst` at `src`.
-func CopyFile(src, dst string) error {
-	in, err := os.Open(src)
-	if err != nil {
-		return err
-	}
-	defer in.Close()
-
-	out, err := os.Create(dst)
-	if err != nil {
-		return err
-	}
-
-	_, err = io.Copy(out, in)
-	if err != nil {
-		out.Close()
-		return err
-	}
-	return out.Close()
-}
-
-// join takes a list of errors and joins them into a single error
 func Join(errs ...error) error {
 	if len(errs) == 1 {
 		return errs[0]
@@ -49,42 +22,3 @@ func Join(errs ...error) error {
 	}
 	return errors.New("[" + strings.Join(msgs, ", ") + "]")
 }
-
-// remove removes the given file or directory from disk.
-func Remove(location string) error {
-	fi, err := os.Lstat(location)
-	if err != nil {
-		if os.IsNotExist(err) {
-			return nil
-		}
-		return fmt.Errorf("remove: error checking for existence of `%s`: %w", location, err)
-	}
-	if fi.IsDir() {
-		err = os.RemoveAll(location)
-	} else {
-		err = os.Remove(location)
-	}
-	if err != nil {
-		return fmt.Errorf("remove: error removing `%s`: %w", location, err)
-	}
-	return nil
-}
-
-// buffer takes an io.Writer and returns a wrapped version of the
-// writer that writes to both the original target as well as the returned buffer
-func Buffer(w io.Writer) (io.Writer, *bytes.Buffer) {
-	buffering := &bufferingWriter{buf: bytes.Buffer{}, writer: w}
-	return buffering, &buffering.buf
-}
-
-type bufferingWriter struct {
-	buf    bytes.Buffer
-	writer io.Writer
-}
-
-func (b *bufferingWriter) Write(p []byte) (n int, err error) {
-	if n, err := b.buf.Write(p); err != nil {
-		return n, fmt.Errorf("bufferingWriter: error writing to buffer: %w", err)
-	}
-	return b.writer.Write(p)
-}