Add yaml server config, restart server when ConfigMap changes

internal/quake/server/server.go

@@ -2,17 +2,126 @@ package server
 
 import (
 	"context"
+	"io/ioutil"
+	"log"
 	"os"
-	"os/exec"
+	"path/filepath"
+	"time"
+
+	"sigs.k8s.io/yaml"
+
+	"github.com/criticalstack/quake-kube/internal/util/exec"
 )
 
-func Start(ctx context.Context, dir string) error {
-	cmd := exec.CommandContext(ctx, "ioq3ded", "+set", "dedicated", "1", "+exec", "server.cfg", "+exec", "maps.cfg")
-	cmd.Dir = dir
+type Server struct {
+	Dir           string
+	WatchInterval time.Duration
+	ConfigFile    string
+}
+
+func (s *Server) Start(ctx context.Context) error {
+	cmd := exec.CommandContext(ctx, "ioq3ded", "+set", "dedicated", "1", "+exec", "server.cfg")
+	cmd.Dir = s.Dir
 	cmd.Stdout = os.Stdout
 	cmd.Stderr = os.Stderr
+
+	if s.ConfigFile == "" {
+		cfg := Default()
+		data, err := cfg.Marshal()
+		if err != nil {
+			return err
+		}
+		if err := ioutil.WriteFile(filepath.Join(s.Dir, "baseq3/server.cfg"), data, 0644); err != nil {
+			return err
+		}
+		if err := cmd.Start(); err != nil {
+			return err
+		}
+		return cmd.Wait()
+	}
+
+	if err := s.reload(); err != nil {
+		return err
+	}
 	if err := cmd.Start(); err != nil {
 		return err
 	}
-	return cmd.Wait()
+
+	go func() {
+		if err := cmd.Wait(); err != nil {
+			log.Println(err)
+		}
+	}()
+
+	ch, err := s.watch(ctx)
+	if err != nil {
+		return err
+	}
+
+	for {
+		select {
+		case <-ch:
+			if err := s.reload(); err != nil {
+				return err
+			}
+			if err := cmd.Restart(ctx); err != nil {
+				return err
+			}
+			go func() {
+				if err := cmd.Wait(); err != nil {
+					log.Println(err)
+				}
+			}()
+		case <-ctx.Done():
+			return ctx.Err()
+		}
+	}
+}
+
+func (s *Server) reload() error {
+	data, err := ioutil.ReadFile(s.ConfigFile)
+	if err != nil {
+		return err
+	}
+	var cfg *Config
+	if err := yaml.Unmarshal(data, &cfg); err != nil {
+		return err
+	}
+	data, err = cfg.Marshal()
+	if err != nil {
+		return err
+	}
+	return ioutil.WriteFile(filepath.Join(s.Dir, "baseq3/server.cfg"), data, 0644)
+}
+
+func (s *Server) watch(ctx context.Context) (<-chan struct{}, error) {
+	if s.WatchInterval == 0 {
+		s.WatchInterval = 15 * time.Second
+	}
+	cur, err := os.Stat(s.ConfigFile)
+	if err != nil {
+		return nil, err
+	}
+
+	ch := make(chan struct{})
+
+	go func() {
+		ticker := time.NewTicker(s.WatchInterval)
+		defer ticker.Stop()
+
+		for {
+			select {
+			case <-ticker.C:
+				if fi, err := os.Stat(s.ConfigFile); err == nil {
+					if fi.ModTime().After(cur.ModTime()) {
+						ch <- struct{}{}
+					}
+					cur = fi
+				}
+			case <-ctx.Done():
+				return
+			}
+		}
+	}()
+	return ch, nil
 }