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Implemented tar+xz compression + unit tests for it.

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eleksir
2026-03-27 23:50:27 +03:00
parent b494479128
commit 3620623321
11 changed files with 194 additions and 12 deletions
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2
AGENTS.md
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@@ -182,7 +182,7 @@ Config is JSON (HJSON with comments supported). Default path depends on OS:
| compression_level | `9` | Gzip level (1-9) |
| exclude_patterns | `[]` | Regex patterns to exclude from backup |
| filename_prefix | `backup` | Prefix for backup filename in Content-Disposition header |
| compression_algorithm | `gzip` | Compression algorithm: gzip, bzip2, zstd or lz4 |
| compression_algorithm | `gzip` | Compression algorithm: gzip, bzip2, zstd, lz4 or xz |
## Architecture & Key Patterns

2
README.md
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@@ -57,7 +57,7 @@ AI suggests to fill this section with useful information, despite that all optio
| compression_level | 9 | Gzip compression level for tar.gz archives. | 1 (fastest) to 9 (best compression). Higher values produce smaller files but take longer to compress. |
| exclude_patterns | [] | Regex patterns to exclude from backup. | E.g., `[".*\\.tmp$", "/node_modules/"]`. Files matching any pattern are skipped. |
| filename_prefix | "backup" | Prefix for backup filename in Content-Disposition header. | E.g., "mybackup" produces `mybackup-20260325-092341.tar.gz`. |
| compression_algorithm | "gzip" | Compression algorithm for archive. | Options: "gzip", "bzip2", "zstd", "lz4". Gzip is fastest, bzip2 compresses best, zstd is balanced, lz4 is very fast with moderate compression. |
| compression_algorithm | "gzip" | Compression algorithm for archive. | Options: "gzip", "bzip2", "zstd", "lz4", "xz". Gzip is fastest, lz4 is very fast, zstd is balanced, bzip2 and xz compress best (xz is slowest). |
## Best practices

3
TODO.org
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@@ -9,8 +9,9 @@
- CANCELLED lzo. It has cgo implementaion which depends in liblzo, and native lid that does not support streaming.
- [X] Implemented bzip2 as alternative (pure Go, via github.com/dsnet/compress)
- [X] Implemented zstd as alternative (pure Go, via github.com/klauspost/compress/zstd)
- [X] Implemented lz4 as alternative (pure Go, via github.com/pierrec/lz4)
- [X] Implemented xz as alternative (pure Go, via github.com/ulikunitz/xz)
- [X] Add compression_algorithm config option
- Note: xz and lz4 can be added later if needed (pure Go libs available)
** DONE Configurable filename prefix
- [X] Move "backup" prefix to config (currently hardcoded in newServer.go)

2
data/config_example.json
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@@ -47,6 +47,6 @@
/* Prefix for backup filename in Content-Disposition header. */
"filename_prefix": "backup",
/* Compression algorithm: gzip, bzip2, zstd or lz4. */
/* Compression algorithm: gzip, bzip2, zstd, lz4 or xz. */
"compression_algorithm": "gzip"
}

12
go.mod
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@@ -2,10 +2,12 @@ module backer
go 1.25
require github.com/hjson/hjson-go v3.3.0+incompatible
require (
github.com/dsnet/compress v0.0.1 // indirect
github.com/klauspost/compress v1.18.5 // indirect
github.com/pierrec/lz4 v2.6.1+incompatible // indirect
github.com/dsnet/compress v0.0.1
github.com/hjson/hjson-go v3.3.0+incompatible
github.com/klauspost/compress v1.18.5
github.com/pierrec/lz4 v2.6.1+incompatible
github.com/ulikunitz/xz v0.5.15
)
require github.com/frankban/quicktest v1.14.6 // indirect

14
go.sum
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@@ -1,12 +1,26 @@
github.com/creack/pty v1.1.9/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ33E=
github.com/dsnet/compress v0.0.1 h1:PlZu0n3Tuv04TzpfPbrnI0HW/YwodEXDS+oPKahKF0Q=
github.com/dsnet/compress v0.0.1/go.mod h1:Aw8dCMJ7RioblQeTqt88akK31OvO8Dhf5JflhBbQEHo=
github.com/dsnet/golib v0.0.0-20171103203638-1ea166775780/go.mod h1:Lj+Z9rebOhdfkVLjJ8T6VcRQv3SXugXy999NBtR9aFY=
github.com/frankban/quicktest v1.14.6 h1:7Xjx+VpznH+oBnejlPUj8oUpdxnVs4f8XU8WnHkI4W8=
github.com/frankban/quicktest v1.14.6/go.mod h1:4ptaffx2x8+WTWXmUCuVU6aPUX1/Mz7zb5vbUoiM6w0=
github.com/google/go-cmp v0.5.9 h1:O2Tfq5qg4qc4AmwVlvv0oLiVAGB7enBSJ2x2DqQFi38=
github.com/google/go-cmp v0.5.9/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
github.com/hjson/hjson-go v3.3.0+incompatible h1:Rqr+Ya+0aCJMjaE4s8E9YKvuJLuLVpEvz4ONum52vnI=
github.com/hjson/hjson-go v3.3.0+incompatible/go.mod h1:qsetwF8NlsTsOTwZTApNlTCerV+b2GjYRRcIk4JMFio=
github.com/klauspost/compress v1.4.1/go.mod h1:RyIbtBH6LamlWaDj8nUwkbUhJ87Yi3uG0guNDohfE1A=
github.com/klauspost/compress v1.18.5 h1:/h1gH5Ce+VWNLSWqPzOVn6XBO+vJbCNGvjoaGBFW2IE=
github.com/klauspost/compress v1.18.5/go.mod h1:cwPg85FWrGar70rWktvGQj8/hthj3wpl0PGDogxkrSQ=
github.com/klauspost/cpuid v1.2.0/go.mod h1:Pj4uuM528wm8OyEC2QMXAi2YiTZ96dNQPGgoMS4s3ek=
github.com/kr/pretty v0.3.1 h1:flRD4NNwYAUpkphVc1HcthR4KEIFJ65n8Mw5qdRn3LE=
github.com/kr/pretty v0.3.1/go.mod h1:hoEshYVHaxMs3cyo3Yncou5ZscifuDolrwPKZanG3xk=
github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
github.com/kr/text v0.2.0/go.mod h1:eLer722TekiGuMkidMxC/pM04lWEeraHUUmBw8l2grE=
github.com/pierrec/lz4 v2.6.1+incompatible h1:9UY3+iC23yxF0UfGaYrGplQ+79Rg+h/q9FV9ix19jjM=
github.com/pierrec/lz4 v2.6.1+incompatible/go.mod h1:pdkljMzZIN41W+lC3N2tnIh5sFi+IEE17M5jbnwPHcY=
github.com/pkg/diff v0.0.0-20210226163009-20ebb0f2a09e/go.mod h1:pJLUxLENpZxwdsKMEsNbx1VGcRFpLqf3715MtcvvzbA=
github.com/rogpeppe/go-internal v1.9.0 h1:73kH8U+JUqXU8lRuOHeVHaa/SZPifC7BkcraZVejAe8=
github.com/rogpeppe/go-internal v1.9.0/go.mod h1:WtVeX8xhTBvf0smdhujwtBcq4Qrzq/fJaraNFVN+nFs=
github.com/ulikunitz/xz v0.5.6/go.mod h1:2bypXElzHzzJZwzH67Y6wb67pO62Rzfn7BSiF4ABRW8=
github.com/ulikunitz/xz v0.5.15 h1:9DNdB5s+SgV3bQ2ApL10xRc35ck0DuIX/isZvIk+ubY=
github.com/ulikunitz/xz v0.5.15/go.mod h1:nbz6k7qbPmH4IRqmfOplQw/tblSgqTqBwxkY0oWt/14=

4
internal/backer/loadConfig.go
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@@ -142,8 +142,8 @@ func LoadConfig(path string) error {
log.Warnf("Config option compression_algorithm is not set, fallback to %s", C.CompressionAlgorithm)
}
if C.CompressionAlgorithm != "gzip" && C.CompressionAlgorithm != "bzip2" && C.CompressionAlgorithm != "zstd" && C.CompressionAlgorithm != "lz4" {
return fmt.Errorf("Compression_algorithm must be gzip, bzip2, zstd or lz4, got %s", C.CompressionAlgorithm)
if C.CompressionAlgorithm != "gzip" && C.CompressionAlgorithm != "bzip2" && C.CompressionAlgorithm != "zstd" && C.CompressionAlgorithm != "lz4" && C.CompressionAlgorithm != "xz" {
return fmt.Errorf("Compression_algorithm must be gzip, bzip2, zstd, lz4 or xz, got %s", C.CompressionAlgorithm)
}
// Compile exclude patterns.

21
internal/backer/loadConfig_test.go
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@@ -295,6 +295,27 @@ func TestLoadConfigCompressionAlgorithmLz4(t *testing.T) {
}
}
// TestLoadConfigCompressionAlgorithmXz tests xz compression algorithm.
func TestLoadConfigCompressionAlgorithmXz(t *testing.T) {
config := `{
"user": "test",
"password": "test",
"directories": ["../../test_data/test1/foo"],
"nohttps": true,
"compression_algorithm": "xz"
}`
tmpFile := writeTempConfig(t, config)
err := LoadConfig(tmpFile)
if err != nil {
t.Errorf("Expected no error, got %v", err)
}
if C.CompressionAlgorithm != "xz" {
t.Errorf("C.CompressionAlgorithm should be xz, got %s", C.CompressionAlgorithm)
}
}
// TestLoadConfigCompressionAlgorithmInvalid tests invalid compression algorithm.
func TestLoadConfigCompressionAlgorithmInvalid(t *testing.T) {
config := `{

4
internal/backer/newServer.go
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@@ -91,6 +91,10 @@ func NewServer(configPath string) (*http.Server, error) {
archive = CreateTarLz4Stream(ctx, files)
extension = "tar.lz4"
case "xz":
archive = CreateTarXzStream(ctx, files)
extension = "tar.xz"
default:
archive = CreateTarGzStream(ctx, files)
extension = "tar.gz"

140
internal/backer/utils.go
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@@ -15,6 +15,7 @@ import (
"github.com/dsnet/compress/bzip2"
"github.com/klauspost/compress/zstd"
"github.com/pierrec/lz4"
"github.com/ulikunitz/xz"
)
// CreateTarGzStream takes a list of files and returns a reader that reads from a tar archive containing these files.
@@ -590,6 +591,145 @@ func CreateTarLz4Stream(ctx context.Context, filepaths []string) io.ReadCloser {
return pr
}
// CreateTarXzStream takes a list of files and returns a reader that reads from an xz-compressed tar archive.
func CreateTarXzStream(ctx context.Context, filepaths []string) io.ReadCloser {
pr, pw := io.Pipe()
go func() {
var pipeErr error
closePipeWithError := func(err error) {
if pipeErr != nil {
return
}
pipeErr = err
pw.CloseWithError(err)
}
defer func() {
if pipeErr == nil {
pw.Close()
}
}()
xw, err := xz.NewWriter(pw)
if err != nil {
closePipeWithError(fmt.Errorf("xz writer error: %w", err))
return
}
defer func() {
if pipeErr == nil {
if err := xw.Close(); err != nil {
if !isPipeClosedError(err) {
log.Errorf("Failed to close xz writer: %v", err)
}
}
}
}()
tw := tar.NewWriter(xw)
defer func() {
if pipeErr == nil {
if err := tw.Close(); err != nil {
if !isPipeClosedError(err) {
log.Errorf("Failed to close tar writer: %v", err)
}
}
}
}()
for _, fpath := range filepaths {
var (
err error
linkTarget string
)
select {
case <-ctx.Done():
closePipeWithError(ctx.Err())
return
default:
}
log.Debugf("Adding file: %s", fpath)
st, err := os.Lstat(fpath)
if err != nil {
log.Warnf("Skipping %s: %v", fpath, err)
continue
}
if st.Mode()&os.ModeSymlink != 0 {
linkTarget, err = os.Readlink(fpath)
if err != nil {
log.Warnf("Skipping %s: readlink failed: %v", fpath, err)
continue
}
}
if st.Mode()&os.ModeSocket != 0 {
log.Debugf("Skipping socket: %s", fpath)
continue
}
header, err := tar.FileInfoHeader(st, linkTarget)
if err != nil {
log.Warnf("Skipping %s: tar header failed: %v", fpath, err)
continue
}
header.Format = tar.FormatGNU
header.Name = strings.TrimPrefix(filepath.ToSlash(filepath.Clean(fpath)), "/")
mode := st.Mode()
if err := writeWithContext(ctx, func() error {
return tw.WriteHeader(header)
}); err != nil {
closePipeWithError(err)
return
}
if mode.IsRegular() {
f, err := os.Open(fpath)
if err != nil {
log.Warnf("Skipping %s: open failed: %v", fpath, err)
continue
}
err = copyWithContext(ctx, tw, f)
if e := f.Close(); e != nil {
log.Warnf("Failed to close file %s: %v", fpath, e)
}
if err != nil {
log.Warnf("Skipping %s: copy failed: %v", fpath, err)
continue
}
}
}
}()
return pr
}
// isPipeClosedError checks if the error is due to a closed pipe.
func isPipeClosedError(err error) bool {
if err == nil {

2
llms.txt
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@@ -62,7 +62,7 @@ curl -u user:pass https://server:8086/archive -o backup.tar.gz
| compression_level | 9 | Gzip level (1-9) |
| exclude_patterns | [] | Regex patterns to exclude from backup |
| filename_prefix | backup | Prefix for backup filename in Content-Disposition header |
| compression_algorithm | gzip | Compression algorithm (gzip, bzip2, zstd or lz4) |
| compression_algorithm | gzip | Compression algorithm (gzip, bzip2, zstd, lz4 or xz) |
## Key Patterns