domaininfo: Do not reload the database periodically

It is not expected that the user modifies the domaininfo database behind
chasquid's back, and reloading it can be somewhat expensive.

So this patch removes the periodic reload, and instead makes it triggered
by SIGHUP so the user can trigger a reload manually if needed.

chasquid.go

@@ -18,6 +18,7 @@ import (
 
 	"blitiri.com.ar/go/chasquid/internal/config"
 	"blitiri.com.ar/go/chasquid/internal/courier"
+	"blitiri.com.ar/go/chasquid/internal/domaininfo"
 	"blitiri.com.ar/go/chasquid/internal/dovecot"
 	"blitiri.com.ar/go/chasquid/internal/maillog"
 	"blitiri.com.ar/go/chasquid/internal/normalize"
@@ -70,8 +71,6 @@ func main() {
 
 	initMailLog(conf.MailLogPath)
 
-	go signalHandler()
-
 	if conf.MonitoringAddress != "" {
 		go launchMonitoringServer(conf)
 	}
@@ -132,7 +131,11 @@ func main() {
 	// as a remote domain (for loops, alias resolutions, etc.).
 	s.AddDomain("localhost")
 
-	dinfo := s.InitDomainInfo(conf.DataDir + "/domaininfo")
+	dinfo, err := domaininfo.New(conf.DataDir + "/domaininfo")
+	if err != nil {
+		log.Fatalf("Error opening domain info database: %v", err)
+	}
+	s.SetDomainInfo(dinfo)
 
 	stsCache, err := sts.NewCache(conf.DataDir + "/sts-cache")
 	if err != nil {
@@ -169,6 +172,8 @@ func main() {
 		log.Fatalf("No address to listen on")
 	}
 
+	go signalHandler(dinfo, s)
+
 	s.ListenAndServe()
 }
 
@@ -212,7 +217,7 @@ func initMailLog(path string) {
 	}
 }
 
-func signalHandler() {
+func signalHandler(dinfo *domaininfo.DB, srv *smtpsrv.Server) {
 	var err error
 
 	signals := make(chan os.Signal, 1)
@@ -221,6 +226,8 @@ func signalHandler() {
 	for {
 		switch sig := <-signals; sig {
 		case syscall.SIGHUP:
+			log.Infof("Received SIGHUP, reloading")
+
 			// SIGHUP triggers a reopen of the log files. This is used for log
 			// rotation.
 			err = log.Default.Reopen()
@@ -232,6 +239,17 @@ func signalHandler() {
 			if err != nil {
 				log.Fatalf("Error reopening maillog: %v", err)
 			}
+
+			// We don't want to reload the domain info database periodically,
+			// as it can be expensive, and it is not expected that the user
+			// changes this behind chasquid's back.
+			err = dinfo.Reload()
+			if err != nil {
+				log.Fatalf("Error reloading domain info: %v", err)
+			}
+
+			// Also trigger a server reload.
+			srv.Reload()
 		case syscall.SIGTERM, syscall.SIGINT:
 			log.Fatalf("Got signal to exit: %v", sig)
 		default:

internal/smtpsrv/server.go

@@ -138,15 +138,9 @@ func (s *Server) SetAliasesConfig(suffixSep, dropChars string) {
 	s.aliasesR.ResolveHook = path.Join(s.HookPath, "alias-resolve")
 }
 
-// InitDomainInfo initializes the domain info database.
-func (s *Server) InitDomainInfo(dir string) *domaininfo.DB {
-	var err error
-	s.dinfo, err = domaininfo.New(dir)
-	if err != nil {
-		log.Fatalf("Error opening domain info database: %v", err)
-	}
-
-	return s.dinfo
+// SetDomainInfo sets the domain info database to use.
+func (s *Server) SetDomainInfo(dinfo *domaininfo.DB) {
+	s.dinfo = dinfo
 }
 
 // InitQueue initializes the queue.
@@ -168,8 +162,8 @@ func (s *Server) InitQueue(path string, localC, remoteC courier.Courier) {
 		})
 }
 
-// periodicallyReload some of the server's information, such as aliases and
-// the user databases.
+// periodicallyReload some of the server's information that can be changed
+// without the server knowing, such as aliases and the user databases.
 func (s *Server) periodicallyReload() {
 	if reloadEvery == nil {
 		return
@@ -177,20 +171,20 @@ func (s *Server) periodicallyReload() {
 
 	//lint:ignore SA1015 This lasts the program's lifetime.
 	for range time.Tick(*reloadEvery) {
-		err := s.aliasesR.Reload()
-		if err != nil {
-			log.Errorf("Error reloading aliases: %v", err)
-		}
+		s.Reload()
+	}
+}
 
-		err = s.authr.Reload()
-		if err != nil {
-			log.Errorf("Error reloading authenticators: %v", err)
-		}
+func (s *Server) Reload() {
+	// Note that any error while reloading is fatal: this way, if there is an
+	// unexpected error it can be detected (and corrected) quickly, instead of
+	// much later (e.g. upon restart) when it might be harder to debug.
+	if err := s.aliasesR.Reload(); err != nil {
+		log.Fatalf("Error reloading aliases: %v", err)
+	}
 
-		err = s.dinfo.Reload()
-		if err != nil {
-			log.Errorf("Error reloading domaininfo: %v", err)
-		}
+	if err := s.authr.Reload(); err != nil {
+		log.Fatalf("Error reloading authenticators: %v", err)
 	}
 }
 

internal/smtpsrv/server_test.go

@@ -11,6 +11,7 @@ import (
 	"time"
 
 	"blitiri.com.ar/go/chasquid/internal/aliases"
+	"blitiri.com.ar/go/chasquid/internal/domaininfo"
 	"blitiri.com.ar/go/chasquid/internal/maillog"
 	"blitiri.com.ar/go/chasquid/internal/testlib"
 	"blitiri.com.ar/go/chasquid/internal/userdb"
@@ -593,7 +594,13 @@ func realMain(m *testing.M) int {
 		s.AddAddr(submissionTLSAddr, ModeSubmissionTLS)
 
 		s.InitQueue(tmpDir+"/queue", localC, remoteC)
-		s.InitDomainInfo(tmpDir + "/domaininfo")
+
+		dinfo, err := domaininfo.New(tmpDir + "/domaininfo")
+		if err != nil {
+			fmt.Printf("Error initializing domaininfo: %v", err)
+			return 1
+		}
+		s.SetDomainInfo(dinfo)
 
 		udb := userdb.New("/dev/null")
 		udb.AddUser("testuser", "testpasswd")