Add support of Unix socket (#912)

Reviewed-on: https://kolaente.dev/vikunja/api/pulls/912
Reviewed-by: konrad <konrad@kola-entertainments.de>
Co-authored-by: andreymal <andriyano-31@mail.ru>
Co-committed-by: andreymal <andriyano-31@mail.ru>

config.yml.sample

@@ -5,6 +5,10 @@ service:
   JWTSecret: "<jwt-secret>"
   # The interface on which to run the webserver
   interface: ":3456"
+  # Path to Unix socket. If set, it will be created and used instead of tcp
+  unixsocket:
+  # Permission bits for the Unix socket. Note that octal values must be prefixed by "0o", e.g. 0o660
+  unixsocketmode:
   # The URL of the frontend, used to send password reset emails.
   frontendurl: ""
   # The base path on the file system where the binary and assets are.

pkg/cmd/web.go

@@ -18,6 +18,7 @@ package cmd
 
 import (
 	"context"
+	"net"
 	"os"
 	"os/signal"
 	"time"
@@ -29,7 +30,9 @@ import (
 	"code.vikunja.io/api/pkg/log"
 	"code.vikunja.io/api/pkg/routes"
 	"code.vikunja.io/api/pkg/swagger"
+	"code.vikunja.io/api/pkg/utils"
 	"code.vikunja.io/api/pkg/version"
+	"github.com/labstack/echo/v4"
 	"github.com/spf13/cobra"
 )
 
@@ -37,6 +40,31 @@ func init() {
 	rootCmd.AddCommand(webCmd)
 }
 
+func setupUnixSocket(e *echo.Echo) error {
+	path := config.ServiceUnixSocket.GetString()
+
+	// Remove old unix socket that may have remained after a crash
+	if err := os.Remove(path); err != nil && !os.IsNotExist(err) {
+		return err
+	}
+
+	if config.ServiceUnixSocketMode.Get() != nil {
+		// Use Umask instead of Chmod to prevent insecure race condition
+		// (no-op on Windows)
+		mode := config.ServiceUnixSocketMode.GetInt()
+		oldmask := utils.Umask(0o777 &^ mode)
+		defer utils.Umask(oldmask)
+	}
+
+	l, err := net.Listen("unix", path)
+	if err != nil {
+		return err
+	}
+
+	e.Listener = l
+	return nil
+}
+
 var webCmd = &cobra.Command{
 	Use:   "web",
 	Short: "Starts the rest api web server",
@@ -56,6 +84,12 @@ var webCmd = &cobra.Command{
 		routes.RegisterRoutes(e)
 		// Start server
 		go func() {
+			// Listen unix socket if needed (ServiceInterface will be ignored)
+			if config.ServiceUnixSocket.GetString() != "" {
+				if err := setupUnixSocket(e); err != nil {
+					e.Logger.Fatal(err)
+				}
+			}
 			if err := e.Start(config.ServiceInterface.GetString()); err != nil {
 				e.Logger.Info("shutting down...")
 			}

pkg/config/config.go

@@ -38,6 +38,8 @@ const (
 	// #nosec
 	ServiceJWTSecret       Key = `service.JWTSecret`
 	ServiceInterface       Key = `service.interface`
+	ServiceUnixSocket      Key = `service.unixsocket`
+	ServiceUnixSocketMode  Key = `service.unixsocketmode`
 	ServiceFrontendurl     Key = `service.frontendurl`
 	ServiceEnableCaldav    Key = `service.enablecaldav`
 	ServiceRootpath        Key = `service.rootpath`
@@ -224,6 +226,7 @@ func InitDefaultConfig() {
 	// Service
 	ServiceJWTSecret.setDefault(random)
 	ServiceInterface.setDefault(":3456")
+	ServiceUnixSocket.setDefault("")
 	ServiceFrontendurl.setDefault("")
 	ServiceEnableCaldav.setDefault(true)
 

pkg/utils/umask_unix.go

@@ -0,0 +1,25 @@
+// Vikunja is a to-do list application to facilitate your life.
+// Copyright 2018-2021 Vikunja and contributors. All rights reserved.
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public Licensee as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public Licensee for more details.
+//
+// You should have received a copy of the GNU Affero General Public Licensee
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+// +build !windows
+
+package utils
+
+import "golang.org/x/sys/unix"
+
+func Umask(mask int) int {
+	return unix.Umask(mask)
+}

pkg/utils/umask_windows.go

@@ -0,0 +1,24 @@
+// Vikunja is a to-do list application to facilitate your life.
+// Copyright 2018-2021 Vikunja and contributors. All rights reserved.
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public Licensee as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public Licensee for more details.
+//
+// You should have received a copy of the GNU Affero General Public Licensee
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+// +build windows
+
+package utils
+
+// Windows doesn't provide the umask syscall, so there is a no-op stub.
+func Umask(mask int) int {
+	return 077
+}