feat(archive): add concurrency control for archive operations

Introduce a new `archiveWorkers` channel to limit the number of concurrent archive operations. When the limit is reached, new requests will receive a 429 Too Many Requests response. This prevents resource exhaustion and improves system stability. The maximum number of workers can be configured via the `--max-archive-workers` CLI option.

Author: OlegChuev-MD

README.md

@@ -28,7 +28,7 @@ Will generate executable file "main" in current directory.
 Start server on port 8080, root directory is current working directory:
 ```sh
 ghfs -l 8080
-``` 
+```
 
 Start server on port 8080, root directory is /usr/share/doc:
 ```sh
@@ -258,7 +258,10 @@ ghfs [options]
 -A|--global-archive
     Allow user to download the whole contents of current directory for all url paths.
     A download link will appear on top part of the page.
-    Make sure there is no circular symbol links.
+--max-archive-workers <number>
+    Maximum number of concurrent archive operations.
+    Set to -1 for unlimited (default).
+    When the limit is reached, new archive requests will receive 429 Too Many Requests.
 --archive <url-path> ...
 --archive-user <separator><url-path>[<separator><allowed-username>...] ...
     Allow user to download the whole contents of current directory for specific url paths(and sub paths).
@@ -304,7 +307,7 @@ ghfs [options]
 -S|--show <wildcard> ...
 -SD|--show-dir <wildcard> ...
 -SF|--show-file <wildcard> ...
-    If specified, files or directories match wildcards(except hidden by hide option) will be shown. 
+    If specified, files or directories match wildcards(except hidden by hide option) will be shown.
 
 -H|--hide <wildcard> ...
 -HD|--hide-dir <wildcard> ...

src/param/cli.go

@@ -2,12 +2,13 @@ package param
 
 import (
 	"errors"
-	"mjpclab.dev/ghfs/src/goNixArgParser"
-	"mjpclab.dev/ghfs/src/goVirtualHost"
-	"mjpclab.dev/ghfs/src/serverError"
 	"net/http"
 	"os"
 	"strings"
+
+	"mjpclab.dev/ghfs/src/goNixArgParser"
+	"mjpclab.dev/ghfs/src/goVirtualHost"
+	"mjpclab.dev/ghfs/src/serverError"
 )
 
 var cliCmd = NewCliCmd()
@@ -147,6 +148,9 @@ func NewCliCmd() *goNixArgParser.Command {
 	err = options.AddFlagValues("archivedirsusers", "--archive-dir-user", "", nil, "file system path that allow archive files for specific users, <sep><fs-path>[<sep><user>...]")
 	serverError.CheckFatal(err)
 
+	err = options.AddFlagValue("maxarchiveworkers", "--max-archive-workers", "", "-1", "maximum number of concurrent archive operations (-1 for unlimited)")
+	serverError.CheckFatal(err)
+
 	err = options.AddFlag("globalcors", "--global-cors", "GHFS_GLOBAL_CORS", "enable CORS headers for all directories")
 	serverError.CheckFatal(err)
 
@@ -436,6 +440,8 @@ func CmdResultsToParams(results []*goNixArgParser.ParseResult) (params Params, e
 		archiveDirsUsers, _ := result.GetStrings("archivedirsusers")
 		param.ArchiveDirsUsers = SplitAllKeyValues(archiveDirsUsers)
 
+		param.ArchiveMaxWorkers, _ = result.GetInt("maxarchiveworkers")
+
 		// global restrict access
 		if result.HasKey("globalrestrictaccess") {
 			param.GlobalRestrictAccess, _ = result.GetStrings("globalrestrictaccess")
@@ -464,7 +470,7 @@ func CmdResultsToParams(results []*goNixArgParser.ParseResult) (params Params, e
 		// certificate
 		certFiles, _ := result.GetStrings("certs")
 		keyFiles, _ := result.GetStrings("keys")
-		param.CertKeyPaths, es = goVirtualHost.CertsKeysToPairs(certFiles, keyFiles)
+		param.CertKeyPaths, _ = goVirtualHost.CertsKeysToPairs(certFiles, keyFiles)
 
 		// listen
 		listens, _ := result.GetStrings("listens")

src/param/main.go

@@ -1,11 +1,12 @@
 package param
 
 import (
+	"os"
+	"path/filepath"
+
 	"mjpclab.dev/ghfs/src/middleware"
 	"mjpclab.dev/ghfs/src/serverError"
 	"mjpclab.dev/ghfs/src/util"
-	"os"
-	"path/filepath"
 )
 
 type Param struct {
@@ -56,11 +57,13 @@ type Param struct {
 	DeleteDirs      []string
 	DeleteDirsUsers [][]string // [][path, user...]
 
-	GlobalArchive    bool
-	ArchiveUrls      []string
-	ArchiveUrlsUsers [][]string // [][path, user...]
-	ArchiveDirs      []string
-	ArchiveDirsUsers [][]string // [][path, user...]
+	GlobalArchive     bool
+	ArchiveUrls       []string
+	ArchiveUrlsUsers  [][]string // [][path, user...]
+	ArchiveDirs       []string
+	ArchiveDirsUsers  [][]string // [][path, user...]
+	ArchiveMaxWorkers int
+	ArchivationsSem   chan struct{}
 
 	GlobalCors bool
 	CorsUrls   []string
@@ -163,6 +166,10 @@ func (param *Param) Normalize() (errs []error) {
 	param.DeleteDirs = NormalizeFsPaths(param.DeleteDirs)
 	param.ArchiveUrls = NormalizeUrlPaths(param.ArchiveUrls)
 	param.ArchiveDirs = NormalizeFsPaths(param.ArchiveDirs)
+	if param.ArchiveMaxWorkers > 0 {
+		param.ArchivationsSem = make(chan struct{}, param.ArchiveMaxWorkers)
+	}
+
 	param.CorsUrls = NormalizeUrlPaths(param.CorsUrls)
 	param.CorsDirs = NormalizeFsPaths(param.CorsDirs)
 

src/serverHandler/aliasHandler.go

@@ -1,16 +1,17 @@
 package serverHandler
 
 import (
+	"net/http"
+	"regexp"
+	"strconv"
+	"strings"
+
 	"mjpclab.dev/ghfs/src/middleware"
 	"mjpclab.dev/ghfs/src/param"
 	"mjpclab.dev/ghfs/src/serverLog"
 	"mjpclab.dev/ghfs/src/tpl/theme"
 	"mjpclab.dev/ghfs/src/user"
 	"mjpclab.dev/ghfs/src/util"
-	"net/http"
-	"regexp"
-	"strconv"
-	"strings"
 )
 
 var defaultHandler = http.NotFoundHandler()
@@ -48,6 +49,8 @@ type aliasHandler struct {
 	archive *hierarchyAvailability
 	cors    *hierarchyAvailability
 
+	archiveWorkers chan struct{}
+
 	globalRestrictAccess []string
 	restrictAccessUrls   pathStringsList
 	restrictAccessDirs   pathStringsList
@@ -120,21 +123,8 @@ func (h *aliasHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 
 		if session.isMutate && h.mutate(w, r, session, data) {
 			return
-		} else if session.isArchive {
-			switch session.archiveFormat {
-			case tarFmt:
-				if h.tar(w, r, session, data) {
-					return
-				}
-			case tgzFmt:
-				if h.tgz(w, r, session, data) {
-					return
-				}
-			case zipFmt:
-				if h.zip(w, r, session, data) {
-					return
-				}
-			}
+		} else if session.isArchive && h.createArchive(w, r, session, data) {
+			return
 		}
 	}
 
@@ -152,6 +142,29 @@ func (h *aliasHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	}
 }
 
+func (h *aliasHandler) createArchive(w http.ResponseWriter, r *http.Request, session *sessionContext, data *responseData) bool {
+	if h.archiveWorkers != nil {
+		select {
+		case h.archiveWorkers <- struct{}{}:
+			defer func() { <-h.archiveWorkers }()
+		default:
+			data.Status = http.StatusTooManyRequests
+			return false
+		}
+	}
+
+	switch session.archiveFormat {
+	case tarFmt:
+		return h.tar(w, r, session, data)
+	case tgzFmt:
+		return h.tgz(w, r, session, data)
+	case zipFmt:
+		return h.zip(w, r, session, data)
+	}
+
+	return false
+}
+
 func newAliasHandler(
 	p *param.Param,
 	vhostCtx *vhostContext,
@@ -179,6 +192,8 @@ func newAliasHandler(
 		toHttpsPort:  p.ToHttpsPort,
 		defaultSort:  p.DefaultSort,
 
+		archiveWorkers: p.ArchivationsSem,
+
 		users:  vhostCtx.users,
 		theme:  vhostCtx.theme,
 		logger: vhostCtx.logger,