From f97ce11734c8309213eb96e446426ec6d5d30eda Mon Sep 17 00:00:00 2001
From: "J. Zebedee" <zebedee@code.gripe>
Date: Sun, 11 Aug 2024 03:11:09 -0500
Subject: [PATCH] Add "none" compression type (#457)

* Add "none" compression type

* Add "none" compression to docs

* Use passThroughWriteCloser for "none" compression

* Add test for none compression

---------

Co-authored-by: Frederik Ring <frederik.ring@gmail.com>
---
 cmd/backup/archive.go       | 14 ++++++++++++++
 cmd/backup/config.go        |  2 +-
 cmd/backup/script.go        |  7 ++++++-
 docs/reference/index.md     |  6 +++---
 test/tar/docker-compose.yml | 21 +++++++++++++++++++++
 test/tar/run.sh             | 25 +++++++++++++++++++++++++
 6 files changed, 70 insertions(+), 5 deletions(-)
 create mode 100644 test/tar/docker-compose.yml
 create mode 100755 test/tar/run.sh

diff --git a/cmd/backup/archive.go b/cmd/backup/archive.go
index 87b3466..61f6829 100644
--- a/cmd/backup/archive.go
+++ b/cmd/backup/archive.go
@@ -93,6 +93,8 @@ func compress(paths []string, outFilePath, algo string, concurrency int) error {
 
 func getCompressionWriter(file *os.File, algo string, concurrency int) (io.WriteCloser, error) {
 	switch algo {
+	case "none":
+		return &passThroughWriteCloser{file}, nil
 	case "gz":
 		w, err := pgzip.NewWriterLevel(file, 5)
 		if err != nil {
@@ -165,3 +167,15 @@ func writeTarball(path string, tarWriter *tar.Writer, prefix string) error {
 
 	return nil
 }
+
+type passThroughWriteCloser struct {
+	target io.WriteCloser
+}
+
+func (p *passThroughWriteCloser) Write(b []byte) (int, error) {
+	return p.target.Write(b)
+}
+
+func (p *passThroughWriteCloser) Close() error {
+	return nil
+}
diff --git a/cmd/backup/config.go b/cmd/backup/config.go
index 0fb16de..0609a2f 100644
--- a/cmd/backup/config.go
+++ b/cmd/backup/config.go
@@ -92,7 +92,7 @@ type CompressionType string
 
 func (c *CompressionType) Decode(v string) error {
 	switch v {
-	case "gz", "zst":
+	case "none", "gz", "zst":
 		*c = CompressionType(v)
 		return nil
 	default:
diff --git a/cmd/backup/script.go b/cmd/backup/script.go
index d947e11..56b8af8 100644
--- a/cmd/backup/script.go
+++ b/cmd/backup/script.go
@@ -86,7 +86,12 @@ func (s *script) init() error {
 
 	var bf bytes.Buffer
 	if tErr := tmplFileName.Execute(&bf, map[string]string{
-		"Extension": fmt.Sprintf("tar.%s", s.c.BackupCompression),
+		"Extension": func() string {
+			if s.c.BackupCompression == "none" {
+				return "tar"
+			}
+			return fmt.Sprintf("tar.%s", s.c.BackupCompression)
+		}(),
 	}); tErr != nil {
 		return errwrap.Wrap(tErr, "error executing backup file extension template")
 	}
diff --git a/docs/reference/index.md b/docs/reference/index.md
index ffd76ce..40146d8 100644
--- a/docs/reference/index.md
+++ b/docs/reference/index.md
@@ -43,8 +43,8 @@ You can populate below template according to your requirements and use it as you
 # BACKUP_CRON_EXPRESSION="0 2 * * *"
 
 # The compression algorithm used in conjunction with tar.
-# Valid options are: "gz" (Gzip) and "zst" (Zstd).
-# Note that the selection affects the file extension.
+# Valid options are: "gz" (Gzip), "zst" (Zstd) or "none" (tar only).
+# Default is "gz". Note that the selection affects the file extension.
 
 # BACKUP_COMPRESSION="gz"
 
@@ -60,7 +60,7 @@ You can populate below template according to your requirements and use it as you
 # will result in the same filename for every backup run, which means previous
 # versions will be overwritten on subsequent runs.
 # Extension can be defined literally or via "{{ .Extension }}" template,
-# in which case it will become either "tar.gz" or "tar.zst" (depending
+# in which case it will become either "tar.gz", "tar.zst" or ".tar" (depending
 # on your BACKUP_COMPRESSION setting).
 # The default results in filenames like: `backup-2021-08-29T04-00-00.tar.gz`.
 
diff --git a/test/tar/docker-compose.yml b/test/tar/docker-compose.yml
new file mode 100644
index 0000000..a3f7aa7
--- /dev/null
+++ b/test/tar/docker-compose.yml
@@ -0,0 +1,21 @@
+services:
+  backup:
+    image: offen/docker-volume-backup:${TEST_VERSION:-canary}
+    restart: always
+    environment:
+      BACKUP_FILENAME: test.{{ .Extension }}
+      BACKUP_COMPRESSION: none
+    volumes:
+      - app_data:/backup/app_data:ro
+      - /var/run/docker.sock:/var/run/docker.sock
+      - ${LOCAL_DIR:-./local}:/archive
+
+  offen:
+    image: offen/offen:latest
+    labels:
+      - docker-volume-backup.stop-during-backup=true
+    volumes:
+      - app_data:/var/opt/offen
+
+volumes:
+  app_data:
diff --git a/test/tar/run.sh b/test/tar/run.sh
new file mode 100755
index 0000000..7d8d89d
--- /dev/null
+++ b/test/tar/run.sh
@@ -0,0 +1,25 @@
+#!/bin/sh
+
+set -e
+
+cd "$(dirname "$0")"
+. ../util.sh
+current_test=$(basename $(pwd))
+
+export LOCAL_DIR=$(mktemp -d)
+
+docker compose up -d --quiet-pull
+sleep 5
+
+docker compose exec backup backup
+
+sleep 5
+
+expect_running_containers "2"
+
+tmp_dir=$(mktemp -d)
+tar -xvf "$LOCAL_DIR/test.tar" -C $tmp_dir
+if [ ! -f "$tmp_dir/backup/app_data/offen.db" ]; then
+  fail "Could not find expected file in untared archive."
+fi
+pass "Expected file was found."