Replace Gzip with PGzip (#266)

* Replace Gzip with optimized PGzip. Add concurrency option.

* Add shortened timeout for 'dc down' too.

* Add NaturalNumberZero to allow zero.

* Add test for concurrency=0

* Rename to GZIP_PARALLELISM

* Fix block size. Fix compression level. Fix CI.

* Refactor compression writer fetching. Renamed WholeNumber

README.md

@@ -159,6 +159,13 @@ You can populate below template according to your requirements and use it as you
 
 # BACKUP_COMPRESSION="gz"
 
+# Parallelism level for "gz" (Gzip) compression.
+# Defines how many blocks of data are concurrently processed.
+# Higher values result in faster compression. No effect on decompression
+# Default = 1. Setting this to 0 will use all available threads.
+
+# GZIP_PARALLELISM=1
+
 # The name of the backup file including the extension.
 # Format verbs will be replaced as in `strftime`. Omitting them
 # will result in the same filename for every backup run, which means previous

cmd/backup/archive.go

@@ -8,18 +8,20 @@ package main
 
 import (
 	"archive/tar"
-	"compress/gzip"
 	"fmt"
 	"io"
 	"os"
 	"path"
 	"path/filepath"
+	"runtime"
 	"strings"
 
+	"github.com/klauspost/pgzip"
+
 	"github.com/klauspost/compress/zstd"
 )
 
-func createArchive(files []string, inputFilePath, outputFilePath string, compression string) error {
+func createArchive(files []string, inputFilePath, outputFilePath string, compression string, compressionConcurrency int) error {
 	inputFilePath = stripTrailingSlashes(inputFilePath)
 	inputFilePath, outputFilePath, err := makeAbsolute(inputFilePath, outputFilePath)
 	if err != nil {
@@ -29,7 +31,7 @@ func createArchive(files []string, inputFilePath, outputFilePath string, compres
 		return fmt.Errorf("createArchive: error creating output file path: %w", err)
 	}
 
-	if err := compress(files, outputFilePath, filepath.Dir(inputFilePath), compression); err != nil {
+	if err := compress(files, outputFilePath, filepath.Dir(inputFilePath), compression, compressionConcurrency); err != nil {
 		return fmt.Errorf("createArchive: error creating archive: %w", err)
 	}
 
@@ -53,26 +55,17 @@ func makeAbsolute(inputFilePath, outputFilePath string) (string, string, error)
 	return inputFilePath, outputFilePath, err
 }
 
-func compress(paths []string, outFilePath, subPath string, algo string) error {
+func compress(paths []string, outFilePath, subPath string, algo string, concurrency int) error {
 	file, err := os.Create(outFilePath)
-	var compressWriter io.WriteCloser
 	if err != nil {
 		return fmt.Errorf("compress: error creating out file: %w", err)
 	}
 
 	prefix := path.Dir(outFilePath)
-	switch algo {
+	compressWriter, err := getCompressionWriter(file, algo, concurrency)
-	case "gz":
-		compressWriter = gzip.NewWriter(file)
-	case "zst":
-		compressWriter, err = zstd.NewWriter(file)
 	if err != nil {
-			return fmt.Errorf("compress: zstd error: %w", err)
+		return fmt.Errorf("compress: error getting compression writer: %w", err)
 	}
-	default:
-		return fmt.Errorf("compress: unsupported compression algorithm: %s", algo)
-	}
-
 	tarWriter := tar.NewWriter(compressWriter)
 
 	for _, p := range paths {
@@ -99,6 +92,34 @@ func compress(paths []string, outFilePath, subPath string, algo string) error {
 	return nil
 }
 
+func getCompressionWriter(file *os.File, algo string, concurrency int) (io.WriteCloser, error) {
+	switch algo {
+	case "gz":
+		w, err := pgzip.NewWriterLevel(file, 5)
+		if err != nil {
+			return nil, fmt.Errorf("getCompressionWriter: gzip error: %w", err)
+		}
+
+		if concurrency == 0 {
+			concurrency = runtime.GOMAXPROCS(0)
+		}
+
+		if err := w.SetConcurrency(1<<20, concurrency); err != nil {
+			return nil, fmt.Errorf("getCompressionWriter: error setting concurrency: %w", err)
+		}
+
+		return w, nil
+	case "zst":
+		compressWriter, err := zstd.NewWriter(file)
+		if err != nil {
+			return nil, fmt.Errorf("getCompressionWriter: zstd error: %w", err)
+		}
+		return compressWriter, nil
+	default:
+		return nil, fmt.Errorf("getCompressionWriter: unsupported compression algorithm: %s", algo)
+	}
+}
+
 func writeTarball(path string, tarWriter *tar.Writer, prefix string) error {
 	fileInfo, err := os.Lstat(path)
 	if err != nil {

cmd/backup/config.go

@@ -28,6 +28,7 @@ type Config struct {
 	AwsIamRoleEndpoint            string          `split_words:"true"`
 	AwsPartSize                   int64           `split_words:"true"`
 	BackupCompression             CompressionType `split_words:"true" default:"gz"`
+	GzipParallelism               WholeNumber     `split_words:"true" default:"1"`
 	BackupSources                 string          `split_words:"true" default:"/backup"`
 	BackupFilename                string          `split_words:"true" default:"backup-%Y-%m-%dT%H-%M-%S.{{ .Extension }}"`
 	BackupFilenameExpand          bool            `split_words:"true"`
@@ -131,6 +132,7 @@ func (r *RegexpDecoder) Decode(v string) error {
 	return nil
 }
 
+// NaturalNumber is a type that can be used to decode a positive, non-zero natural number
 type NaturalNumber int
 
 func (n *NaturalNumber) Decode(v string) error {
@@ -148,3 +150,22 @@ func (n *NaturalNumber) Decode(v string) error {
 func (n *NaturalNumber) Int() int {
 	return int(*n)
 }
+
+// WholeNumber is a type that can be used to decode a positive whole number, including zero
+type WholeNumber int
+
+func (n *WholeNumber) Decode(v string) error {
+	asInt, err := strconv.Atoi(v)
+	if err != nil {
+		return fmt.Errorf("config: error converting %s to int", v)
+	}
+	if asInt < 0 {
+		return fmt.Errorf("config: expected a whole, positive number, including zero. Got %d", asInt)
+	}
+	*n = WholeNumber(asInt)
+	return nil
+}
+
+func (n *WholeNumber) Int() int {
+	return int(*n)
+}

cmd/backup/script.go

@@ -503,7 +503,7 @@ func (s *script) createArchive() error {
 		return fmt.Errorf("createArchive: error walking filesystem tree: %w", err)
 	}
 
-	if err := createArchive(filesEligibleForBackup, backupSources, tarFile, s.c.BackupCompression.String()); err != nil {
+	if err := createArchive(filesEligibleForBackup, backupSources, tarFile, s.c.BackupCompression.String(), s.c.GzipParallelism.Int()); err != nil {
 		return fmt.Errorf("createArchive: error compressing backup folder: %w", err)
 	}
 

go.mod

@@ -45,6 +45,7 @@ require (
 	github.com/google/uuid v1.3.0 // indirect
 	github.com/json-iterator/go v1.1.12 // indirect
 	github.com/klauspost/cpuid/v2 v2.2.5 // indirect
+	github.com/klauspost/pgzip v1.2.6
 	github.com/kr/fs v0.1.0 // indirect
 	github.com/kylelemons/godebug v1.1.0 // indirect
 	github.com/mattn/go-colorable v0.1.13 // indirect

go.sum

@@ -458,6 +458,8 @@ github.com/klauspost/compress v1.16.7/go.mod h1:ntbaceVETuRiXiv4DpjP66DpAtAGkEQs
 github.com/klauspost/cpuid/v2 v2.0.1/go.mod h1:FInQzS24/EEf25PyTYn52gqo7WaD8xa0213Md/qVLRg=
 github.com/klauspost/cpuid/v2 v2.2.5 h1:0E5MSMDEoAulmXNFquVs//DdoomxaoTY1kUhbc/qbZg=
 github.com/klauspost/cpuid/v2 v2.2.5/go.mod h1:Lcz8mBdAVJIBVzewtcLocK12l3Y+JytZYpaMropDUws=
+github.com/klauspost/pgzip v1.2.6 h1:8RXeL5crjEUFnR2/Sn6GJNWtSQ3Dk8pq4CL3jvdDyjU=
+github.com/klauspost/pgzip v1.2.6/go.mod h1:Ch1tH69qFZu15pkjo5kYi6mth2Zzwzt50oCQKQE9RUs=
 github.com/konsorten/go-windows-terminal-sequences v1.0.1/go.mod h1:T0+1ngSBFLxvqU3pZ+m/2kptfBszLMUkC4ZK/EgS/cQ=
 github.com/konsorten/go-windows-terminal-sequences v1.0.3/go.mod h1:T0+1ngSBFLxvqU3pZ+m/2kptfBszLMUkC4ZK/EgS/cQ=
 github.com/kr/fs v0.1.0 h1:Jskdu9ieNAYnjxsi0LbQp1ulIKZV1LAFgK1tWhpZgl8=

test/pgzip/run.sh

@@ -0,0 +1,42 @@
+#!/bin/sh
+
+set -e
+
+cd $(dirname $0)
+. ../util.sh
+current_test=$(basename $(pwd))
+
+docker network create test_network
+docker volume create app_data
+
+LOCAL_DIR=$(mktemp -d)
+
+docker run -d -q \
+  --name offen \
+  --network test_network \
+  -v app_data:/var/opt/offen/ \
+  offen/offen:latest
+
+sleep 5
+
+docker run --rm -q \
+  --network test_network \
+  -v app_data:/backup/app_data \
+  -v $LOCAL_DIR:/archive \
+  -v /var/run/docker.sock:/var/run/docker.sock \
+  --env BACKUP_COMPRESSION=gz \
+  --env GZIP_PARALLELISM=0 \
+  --env BACKUP_FILENAME='test.{{ .Extension }}' \
+  --entrypoint backup \
+  offen/docker-volume-backup:${TEST_VERSION:-canary}
+
+tmp_dir=$(mktemp -d)
+tar -xvf "$LOCAL_DIR/test.tar.gz" -C $tmp_dir
+if [ ! -f "$tmp_dir/backup/app_data/offen.db" ]; then
+  fail "Could not find expected file in untared archive."
+fi
+pass "Found relevant files in untared local backup."
+
+# This test does not stop containers during backup. This is happening on
+# purpose in order to cover this setup as well.
+expect_running_containers "1"

test/util.sh

@@ -35,6 +35,9 @@ docker() {
         up)
           shift
           command docker compose up --timeout 3 "$@";;
+        down)
+          shift
+          command docker compose down --timeout 3 "$@";;
         *)
           command docker compose "$@";;
       esac