From 43aeb830691128961e78aa0befb59682ac873645 Mon Sep 17 00:00:00 2001
From: Norwin Roosen <github@nroo.de>
Date: Sun, 10 Feb 2019 13:44:01 +0100
Subject: [PATCH] improve notifier performance

---
 core/cache.go         |  5 ++++-
 core/notifier_xmpp.go | 51 ++++++++++++++++++++++++++++---------------
 core/notifiers.go     | 16 +++++++++-----
 3 files changed, 47 insertions(+), 25 deletions(-)

diff --git a/core/cache.go b/core/cache.go
index 877d6f3..7cf8066 100644
--- a/core/cache.go
+++ b/core/cache.go
@@ -53,11 +53,14 @@ func (results BoxCheckResults) filterChangedFromCache() BoxCheckResults {
 	return remaining
 }
 
-func updateCache(box *Box, results []CheckResult) error {
+func updateCache(box *Box, results []CheckResult) {
 	for _, result := range results {
 		key := fmt.Sprintf("watchcache.%s.%s", box.Id, result.EventID())
 		cache.Set(key+".laststatus", result.Status)
 	}
+}
+
+func writeCache() error {
 	return cache.WriteConfig()
 }
 
diff --git a/core/notifier_xmpp.go b/core/notifier_xmpp.go
index c649573..5fab50c 100644
--- a/core/notifier_xmpp.go
+++ b/core/notifier_xmpp.go
@@ -8,6 +8,8 @@ import (
 	"github.com/spf13/viper"
 )
 
+var client = &xmpp.Client{} // @Hacky
+
 // box config required for the XmppNotifier (TransportConfig.Options)
 type XmppNotifier struct {
 	Recipients []string
@@ -23,6 +25,16 @@ func (n XmppNotifier) New(config TransportConfig) (AbstractNotifier, error) {
 		}
 	}
 
+	// establish connection with server once, and share it accross instances
+	// @Hacky
+	if client.JID() == "" {
+		c, err := connectXmpp()
+		if err != nil {
+			return nil, err
+		}
+		client = c
+	}
+
 	// assign configuration to the notifier after ensuring the correct type.
 	// lesson of this project: golang requires us to fuck around with type
 	// assertions, instead of providing us with proper inheritance.
@@ -53,26 +65,12 @@ func (n XmppNotifier) New(config TransportConfig) (AbstractNotifier, error) {
 }
 
 func (n XmppNotifier) Submit(notification Notification) error {
-	// :TransportConfSourceHack
-	xmppOpts := xmpp.Options{
-		Host:     viper.GetString("xmpp.host"),
-		User:     viper.GetString("xmpp.user"),
-		Password: viper.GetString("xmpp.pass"),
-		Resource: "osem_notify",
-	}
-
-	if viper.GetBool("xmpp.starttls") {
-		xmppOpts.NoTLS = true
-		xmppOpts.StartTLS = true
-	}
-
-	client, err := xmppOpts.NewClient()
-	if err != nil {
-		return err
+	if client.JID() == "" {
+		return fmt.Errorf("xmpp client not correctly initialized!")
 	}
 
 	for _, recipient := range n.Recipients {
-		_, err = client.Send(xmpp.Chat{
+		_, err := client.Send(xmpp.Chat{
 			Remote:  recipient,
 			Subject: notification.Subject,
 			Text:    fmt.Sprintf("%s\n\n%s", notification.Subject, notification.Body),
@@ -83,5 +81,22 @@ func (n XmppNotifier) Submit(notification Notification) error {
 		}
 	}
 
-	return err
+	return nil
+}
+
+func connectXmpp() (*xmpp.Client, error) {
+	// :TransportConfSourceHack
+	xmppOpts := xmpp.Options{
+		Host:     viper.GetString("xmpp.host"),
+		User:     viper.GetString("xmpp.user"),
+		Password: viper.GetString("xmpp.pass"),
+		Resource: "osem_notify",
+	}
+
+	if viper.GetBool("xmpp.starttls") {
+		xmppOpts.NoTLS = true
+		xmppOpts.StartTLS = true
+	}
+
+	return xmppOpts.NewClient()
 }
diff --git a/core/notifiers.go b/core/notifiers.go
index a6ffa8d..14c87ec 100644
--- a/core/notifiers.go
+++ b/core/notifiers.go
@@ -98,11 +98,7 @@ func (results BoxCheckResults) SendNotifications(notifyTypes []string, useCache
 		// update cache (with /all/ changed results to reset status)
 		if useCache {
 			notifyLog.Debug("updating cache")
-			cacheError := updateCache(box, resultsBox)
-			if cacheError != nil {
-				notifyLog.Error("could not cache notification results: ", cacheError)
-				errs = append(errs, cacheError.Error())
-			}
+			updateCache(box, resultsBox)
 		}
 
 		if len(resultsDue) != 0 {
@@ -110,6 +106,15 @@ func (results BoxCheckResults) SendNotifications(notifyTypes []string, useCache
 		}
 	}
 
+	// persist changes to cache
+	if useCache {
+		err := writeCache()
+		if err != nil {
+			log.Error("could not write cache of notification results: ", err)
+			errs = append(errs, err.Error())
+		}
+	}
+
 	if len(errs) != 0 {
 		return fmt.Errorf(strings.Join(errs, "\n"))
 	}
@@ -147,4 +152,3 @@ func ComposeNotification(box *Box, checks []CheckResult) Notification {
 			time.Now().Round(time.Minute), box.Name, errList, resolvedList, box.Id),
 	}
 }
-