From d4e07e81c532bf41fe827d9594cdcb505a7f7028 Mon Sep 17 00:00:00 2001
From: Alex Auvolat <alex@adnab.me>
Date: Fri, 28 Feb 2020 17:42:15 +0100
Subject: Error channels; notify users of restart

---
 main.go   | 12 ++++++------
 server.go | 24 +++++++++++++++++-------
 web.go    |  4 ++--
 3 files changed, 25 insertions(+), 15 deletions(-)

diff --git a/main.go b/main.go
index 339f6c7..e6c3f82 100644
--- a/main.go
+++ b/main.go
@@ -151,6 +151,7 @@ func readRegistration(file string) mxlib.Registration {
 func main() {
 	flag.Parse()
 
+	// Read configuration
 	config_file := readConfig()
 	config = &config_file
 
@@ -163,13 +164,12 @@ func main() {
 	reg_file := readRegistration(config.Registration)
 	registration = &reg_file
 
-	errch, err := StartAppService()
-	if err != nil {
-		log.Fatal(err)
-	}
-
-	StartWeb()
+	// Start appservice and web management interface
+	errch := make(chan error)
+	StartAppService(errch)
+	StartWeb(errch)
 
+	// Wait for an error somewhere
 	err = <-errch
 	if err != nil {
 		log.Fatal(err)
diff --git a/server.go b/server.go
index f3eb898..e914f3b 100644
--- a/server.go
+++ b/server.go
@@ -15,17 +15,17 @@ import (
 
 var mx *mxlib.Client
 
-func StartAppService() (chan error, error) {
+func StartAppService(errch chan error) error {
 	mx = mxlib.NewClient(config.Server, registration.AsToken)
 
 	err := InitDb()
 	if err != nil {
-		return nil, err
+		return err
 	}
 
 	err = mx.RegisterUser(registration.SenderLocalpart)
 	if mxe, ok := err.(*mxlib.MxError); !ok || mxe.ErrCode != "M_USER_IN_USE" {
-		return nil, err
+		return err
 	}
 	if err == nil {
 		// If Easybridge account was created, update avatar and display name
@@ -33,11 +33,11 @@ func StartAppService() (chan error, error) {
 			Path: "easybridge.jpg",
 		})
 		if err != nil {
-			return nil, err
+			return err
 		}
 		err = mx.ProfileDisplayname(ezbrMxId(), fmt.Sprintf("Easybridge (%s)", EASYBRIDGE_SYSTEM_PROTOCOL))
 		if err != nil {
-			return nil, err
+			return err
 		}
 	}
 
@@ -45,7 +45,6 @@ func StartAppService() (chan error, error) {
 	router.HandleFunc("/_matrix/app/v1/transactions/{txnId}", handleTxn)
 	router.HandleFunc("/transactions/{txnId}", handleTxn)
 
-	errch := make(chan error)
 	go func() {
 		log.Printf("Starting HTTP server on %s", config.ASBindAddr)
 		err := http.ListenAndServe(config.ASBindAddr, checkTokenAndLog(router))
@@ -54,7 +53,18 @@ func StartAppService() (chan error, error) {
 		}
 	}()
 
-	return errch, nil
+	// Notify users that Easybridge has restarted
+	go func() {
+		var users []DbAccountConfig
+		db.Model(&DbAccountConfig{}).Select("mx_user_id").Group("mx_user_id").Find(&users)
+		for _, u := range users {
+			ezbrSystemSendf(u.MxUserID,
+				"Easybridge has restarted, please visit %s or open configuration widget to reconnect to your accounts.",
+				config.WebURL)
+		}
+	}()
+
+	return nil
 }
 
 func checkTokenAndLog(handler http.Handler) http.Handler {
diff --git a/web.go b/web.go
index d50d91c..d5846c5 100644
--- a/web.go
+++ b/web.go
@@ -21,7 +21,7 @@ const SESSION_NAME = "easybridge_session"
 var sessionsStore sessions.Store = nil
 var userKeys = map[string]*[32]byte{}
 
-func StartWeb() {
+func StartWeb(errch chan error) {
 	session_key := blake2b.Sum256([]byte(config.SessionKey))
 	sessionsStore = sessions.NewCookieStore(session_key[:])
 
@@ -39,7 +39,7 @@ func StartWeb() {
 	go func() {
 		err := http.ListenAndServe(config.WebBindAddr, logRequest(r))
 		if err != nil {
-			log.Fatal("Cannot start http server: ", err)
+			errch <- err
 		}
 	}()
 }
-- 
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