feat: add machine-id support for hytale servers

Author: naterfute

src/cmd/root.go

@@ -218,9 +218,9 @@ func rootCmdRun(cmd *cobra.Command, _ []string) {
 	for _, serv := range manager.All() {
 		s := serv
 
-		// For each server we encounter make sure the root data directory exists.
+		// For each server ensure the minimal environment is confiugured for the server.
 		if err := s.EnsureDataDirectoryExists(); err != nil {
-			s.Log().Error("could not create root data directory for server: not loading server...")
+			s.Log().Error("could not create base environment for server: not loading server...")
 			continue
 		}
 

src/config/config.go

@@ -182,7 +182,7 @@ type SystemConfiguration struct {
 		// files into containers.
 		Enable bool `yaml:"enabled" default:"false"`
 
-		// Directory is the directory on disk where the generated files will be stored.
+		// Directory is the directory on disk where the generated passwd files will be stored.
 		// This directory may be temporary as it will be re-created whenever Elytra is started.
 		//
 		// This path **WILL** be both written to by Elytra and mounted into containers created by
@@ -193,6 +193,26 @@ type SystemConfiguration struct {
 		Directory string `yaml:"directory" default:"/run/elytra/etc"`
 	} `yaml:"passwd"`
 
+	// MachineID controls the mounting of a generated `/etc/machine-id` file into containers started by Wings.
+	MachineID struct {
+		// Enable controls whether a generated machine-id file should be mounted
+		// into containers.
+		//
+		// By default this option is enabled and Wings will mount an additional
+		// machine-id file into containers.
+		Enable bool `yaml:"enabled" default:"true"`
+
+		// Directory is the directory on disk where the generated machine-id files will be stored.
+		// This directory may be temporary as it will be re-created whenever Wings is started.
+		//
+		// This path **WILL** be both written to by Wings and mounted into containers created by
+		// Wings. If you are running Wings itself in a container, this path will need to be mounted
+		// into the Wings container as the exact path on the host, which should match the value
+		// specified here. If you are using SELinux, you will need to make sure this file has the
+		// correct SELinux context in order for containers to use it.
+		Directory string `yaml:"directory" default:"/run/elytra/machine-id"`
+	} `yaml:"machine_id"`
+
 	// The amount of time in seconds that can elapse before a server's disk space calculation is
 	// considered stale and a re-check should occur. DANGER: setting this value too low can seriously
 	// impact system performance and cause massive I/O bottlenecks and high CPU usage for the Elytra
@@ -744,6 +764,11 @@ func ConfigureDirectories() error {
 		return err
 	}
 
+	log.WithField("path", _config.System.TmpDirectory).Debug("ensuring temporary data directory exists")
+	if err := os.MkdirAll(_config.System.TmpDirectory, 0o700); err != nil {
+		return err
+	}
+
 	log.WithField("path", _config.System.ArchiveDirectory).Debug("ensuring archive data directory exists")
 	if err := os.MkdirAll(_config.System.ArchiveDirectory, 0o700); err != nil {
 		return err
@@ -761,6 +786,13 @@ func ConfigureDirectories() error {
 		}
 	}
 
+	if _config.System.MachineID.Enable {
+		log.WithField("path", _config.System.MachineID.Directory).Debug("ensuring machine-id directory exists")
+		if err := os.MkdirAll(_config.System.MachineID.Directory, 0o755); err != nil {
+			return err
+		}
+	}
+
 	return nil
 }
 

src/server/mounts.go

@@ -28,22 +28,34 @@ func (s *Server) Mounts() []environment.Mount {
 			ReadOnly: false,
 		},
 	}
+	cfg := config.Get()
 
 	// Handle mounting a generated `/etc/passwd` if the feature is enabled.
-	if passwd := config.Get().System.Passwd; passwd.Enable {
-		s.Log().WithFields(log.Fields{"source_path": passwd.Directory}).Info("mouting generated /etc/{group,passwd} to workaround UID/GID issues")
+	if cfg.System.Passwd.Enable {
+		s.Log().WithFields(log.Fields{"source_path": cfg.System.Passwd.Directory}).Info("mouting generated /etc/{group,passwd} to workaround UID/GID issues")
 		m = append(m, environment.Mount{
-			Source:   filepath.Join(passwd.Directory, "group"),
+			Source:   filepath.Join(cfg.System.Passwd.Directory, "group"),
 			Target:   "/etc/group",
 			ReadOnly: true,
 		})
 		m = append(m, environment.Mount{
-			Source:   filepath.Join(passwd.Directory, "passwd"),
+			Source:   filepath.Join(cfg.System.Passwd.Directory, "passwd"),
 			Target:   "/etc/passwd",
 			ReadOnly: true,
 		})
 	}
 
+	if cfg.System.MachineID.Enable {
+		// Hytale wants a machine-id in order to encrypt tokens for the server.
+		// So add a mount to `/etc/machine-id` to a source that contains the
+		// server's UUID without any dashes.
+		m = append(m, environment.Mount{
+			Source:   filepath.Join(cfg.System.MachineID.Directory, s.ID()),
+			Target:   "/etc/machine-id",
+			ReadOnly: true,
+		})
+	}
+
 	// Also include any of this server's custom mounts when returning them.
 	return append(m, s.customMounts()...)
 }

src/server/server.go

@@ -1,11 +1,13 @@
 package server
 
 import (
+	"bytes"
 	"context"
 	"encoding/json"
 	"fmt"
 	"net/http"
 	"os"
+	"path/filepath"
 	"strings"
 	"sync"
 
@@ -259,6 +261,18 @@ func (s *Server) CreateEnvironment() error {
 		return err
 	}
 
+	cfg := config.Get()
+	if cfg.System.MachineID.Enable {
+		// Hytale wants a machine-id in order to encrypt tokens for the server. So
+		// write a machine-id file for the server that contains the server's UUID
+		// without any dashes.
+		p := filepath.Join(cfg.System.MachineID.Directory, s.ID())
+		machineID := append(bytes.ReplaceAll([]byte(s.ID()), []byte{'-'}, []byte{}), '\n')
+		if err := os.WriteFile(p, machineID, 0o644); err != nil {
+			return fmt.Errorf("failed to write machine-id (at '%s') for server '%s': %w", p, s.ID(), err)
+		}
+	}
+
 	return s.Environment.Create()
 }