Implemented tar+parallel gzip compression + unit tests for it.

AGENTS.md

@@ -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, lz4 or xz |
+| compression_algorithm | `gzip` | Compression algorithm: gzip, pgzip, bzip2, zstd, lz4 or xz |
 
 ## Architecture & Key Patterns
 

README.md

@@ -1,6 +1,6 @@
 # Backer
 
-Kind of backup utility. It makes tar.gz on-the-fly out of given in config.json files.
+HTTP/HTTPS backup server that creates compressed archives on-the-fly from configured directories. Supports multiple compression algorithms: gzip, pgzip, bzip2, zstd, lz4, xz.
 
 ## How to build it
 
@@ -8,9 +8,8 @@ Kind of backup utility. It makes tar.gz on-the-fly out of given in config.json f
 make                                    # Build binary
 make build VERSION=0.1.0                # Build with version
 make test                               # Run tests
-backer                                  # Run
+make                                    # Clean + build
-backer --version                        # Show version
+make upgrade                            # Update dependencies
-backer -c /path/to/config.json          # Custom config
 ```
 
 That will produce binary named `backer`. Copy it somewhere in `/usr/local/sbin/backer`, for example. In `data`
@@ -32,32 +31,43 @@ Build, install and configure backer. On your backup storage server you can do
 curl -u username:password https://your_server:8086/archive -o "backup-$(date +%Y%m%d-%H%M%S).tar.gz"
 ```
 
-and you'll get your backup with timestamp in filename, like `backup-20260325-105100.tar.gz`
+The filename and extension depend on your `filename_prefix` and `compression_algorithm` settings.
 
 Of course, something can go wrong, so you must check http status code after downloading backup.
 
 ## About config options
 
-AI suggests to fill this section with useful information, despite that all options described in example config.
+All options described in example config.
 
 | Option | Default value | Wtf | Notes |
 | :--- | :---- | :--- | :--- |
 | address | "0.0.0.0" | Address at which server listens. | In many cases 0.0.0.0 is okay. |
-| port | 8086 | Port at which server binds | Number picked after intel first comercially successful cpu. |
+| port | 8086 | Port at which server binds. | Number picked after intel first commercially successful cpu. |
-| cert | "/path/to/ssl.crt" | Path to ssl certificate file | It is not enforced in obvious form, but you should limit access to certificate at least with file permissions. |
+| cert | — | Path to ssl certificate file. | Required when nohttps is false. |
-| key | "/path/to/ssl.key" | Path to ssl certificates key file | It is not enforced in obvious form, but you should limit access to certificates key at least with file permissions. |
+| key | — | Path to ssl certificates key file. | Required when nohttps is false. |
-| nohttps | false | ability to disable https and use plain http. | This option is for lab experiments or for development needs. In case of this utility you should consider using long enough certificate with well ciphers. |
+| nohttps | false | Disable https and use plain http. | For lab experiments or development. |
-| location | "/archive" | This is static location where curl (or more sophisticated client) should aim to download backup | /archive is okay, but you free to choose something more wild like "/backup", just for giggles. |
+| location | "/archive" | API endpoint path for backup download. | |
-| user | | You should pick up some flashy username for basic auth to prevent unauthorized access to your backup. | Enough said. |
+| user | — | Username for basic auth. | Required. |
-| password | | You should pick up something super-duper secretous to prevent unauthorized access to your backup. | Enough said. |
+| password | — | Password for basic auth. | Required. |
-| log | stderr | Where log messages are directed. If no value set, logs drops to stderr | |
+| log | stderr | Log output file path. | |
-| loglevel | | Verbosity of logs. | Can be error, warn, info, debug. Pick whatever you like. |
+| loglevel | "info" | Verbosity of logs. | Options: error, warn, info, debug. |
-| directories | | An array with directories. Backer can work only with directories, not single files. | Put here all the folders you'd like to backup! |
+| directories | — | Directories to backup. | Required. Array of paths. |
-| backup_timeout | 60 | Timeout in minutes for backup streaming operations. | If a backup takes longer than this, the connection will be terminated. Useful for large backups. Range: 1-1440 minutes (1 day max). |
+| backup_timeout | 60 | Timeout in minutes for backup streaming. | Range: 1-1440 minutes. |
-| 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. |
+| compression_level | 9 | Compression level. | 1 (fastest) to 9 (best compression). |
-| exclude_patterns | [] | Regex patterns to exclude from backup. | E.g., `[".*\\.tmp$", "/node_modules/"]`. Files matching any pattern are skipped. |
+| exclude_patterns | [] | Regex patterns to exclude from backup. | E.g., `[".*\\.tmp$", "/node_modules/"]`. |
-| filename_prefix | "backup" | Prefix for backup filename in Content-Disposition header. | E.g., "mybackup" produces `mybackup-20260325-092341.tar.gz`. |
+| filename_prefix | "backup" | Prefix for backup filename. | E.g., "mybackup" produces `mybackup-20260325-092341.tar.gz`. |
-| 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). |
+| compression_algorithm | "gzip" | Compression algorithm. | Options: gzip, pgzip, bzip2, zstd, lz4, xz. |
+
+## Compression algorithms
+
+| Algorithm | Speed | Compression | Notes |
+| :--- | :--- | :--- | :--- |
+| gzip | Fast | Good | Default. Standard, widely compatible. |
+| pgzip | Fast | Good | Parallel gzip. Uses multiple CPU cores, slightly larger files. |
+| bzip2 | Slow | Better | Pure Go. Good compression, slower than gzip. |
+| zstd | Fast | Very good | Good balance of speed and compression. |
+| lz4 | Fastest | Moderate | Extremely fast, larger files. |
+| xz | Slowest | Best | Best compression, slowest speed. |
 
 ## Best practices
 

data/config_example.json

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

go.mod

@@ -6,6 +6,7 @@ require (
 	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/klauspost/pgzip v1.2.6
 	github.com/pierrec/lz4 v2.6.1+incompatible
 	github.com/ulikunitz/xz v0.5.15
 )

go.sum

@@ -12,6 +12,8 @@ github.com/klauspost/compress v1.4.1/go.mod h1:RyIbtBH6LamlWaDj8nUwkbUhJ87Yi3uG0
 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/klauspost/pgzip v1.2.6 h1:8RXeL5crjEUFnR2/Sn6GJNWtSQ3Dk8pq4CL3jvdDyjU=
+github.com/klauspost/pgzip v1.2.6/go.mod h1:Ch1tH69qFZu15pkjo5kYi6mth2Zzwzt50oCQKQE9RUs=
 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=

internal/backer/loadConfig.go

@@ -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" && C.CompressionAlgorithm != "xz" {
+	if C.CompressionAlgorithm != "gzip" && C.CompressionAlgorithm != "bzip2" && C.CompressionAlgorithm != "zstd" && C.CompressionAlgorithm != "lz4" && C.CompressionAlgorithm != "xz" && C.CompressionAlgorithm != "pgzip" {
-		return fmt.Errorf("Compression_algorithm must be gzip, bzip2, zstd, lz4 or xz, got %s", C.CompressionAlgorithm)
+		return fmt.Errorf("Compression_algorithm must be gzip, bzip2, zstd, lz4, xz or pgzip, got %s", C.CompressionAlgorithm)
 	}
 
 	// Compile exclude patterns.

internal/backer/loadConfig_test.go

@@ -316,6 +316,27 @@ func TestLoadConfigCompressionAlgorithmXz(t *testing.T) {
 	}
 }
 
+// TestLoadConfigCompressionAlgorithmPgzip tests pgzip compression algorithm.
+func TestLoadConfigCompressionAlgorithmPgzip(t *testing.T) {
+	config := `{
+		"user": "test",
+		"password": "test",
+		"directories": ["../../test_data/test1/foo"],
+		"nohttps": true,
+		"compression_algorithm": "pgzip"
+	}`
+	tmpFile := writeTempConfig(t, config)
+
+	err := LoadConfig(tmpFile)
+	if err != nil {
+		t.Errorf("Expected no error, got %v", err)
+	}
+
+	if C.CompressionAlgorithm != "pgzip" {
+		t.Errorf("C.CompressionAlgorithm should be pgzip, got %s", C.CompressionAlgorithm)
+	}
+}
+
 // TestLoadConfigCompressionAlgorithmInvalid tests invalid compression algorithm.
 func TestLoadConfigCompressionAlgorithmInvalid(t *testing.T) {
 	config := `{

internal/backer/newServer.go

@@ -95,6 +95,10 @@ func NewServer(configPath string) (*http.Server, error) {
 			archive = CreateTarXzStream(ctx, files)
 			extension = "tar.xz"
 
+		case "pgzip":
+			archive = CreateTarPgzipStream(ctx, files)
+			extension = "tar.gz"
+
 		default:
 			archive = CreateTarGzStream(ctx, files)
 			extension = "tar.gz"

internal/backer/utils.go

@@ -14,6 +14,7 @@ import (
 
 	"github.com/dsnet/compress/bzip2"
 	"github.com/klauspost/compress/zstd"
+	"github.com/klauspost/pgzip"
 	"github.com/pierrec/lz4"
 	"github.com/ulikunitz/xz"
 )
@@ -730,6 +731,145 @@ func CreateTarXzStream(ctx context.Context, filepaths []string) io.ReadCloser {
 	return pr
 }
 
+// CreateTarPgzipStream takes a list of files and returns a reader that reads from a parallel gzip-compressed tar archive.
+func CreateTarPgzipStream(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()
+			}
+		}()
+
+		gw, err := pgzip.NewWriterLevel(pw, C.CompressionLevel)
+		if err != nil {
+			closePipeWithError(fmt.Errorf("pgzip writer error: %w", err))
+
+			return
+		}
+
+		defer func() {
+			if pipeErr == nil {
+				if err := gw.Close(); err != nil {
+					if !isPipeClosedError(err) {
+						log.Errorf("Failed to close pgzip writer: %v", err)
+					}
+				}
+			}
+		}()
+
+		tw := tar.NewWriter(gw)
+
+		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 {

llms.txt

@@ -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, lz4 or xz) |
+| compression_algorithm | gzip | Compression algorithm (gzip, pgzip, bzip2, zstd, lz4 or xz) |
 
 ## Key Patterns