From b02a84f6cc6721fefd7aeb1ebc23c1bc6fb6b344 Mon Sep 17 00:00:00 2001
From: postmannen <postmannen@gmail.com>
Date: Thu, 16 Dec 2021 11:01:01 +0100
Subject: [PATCH] added config flags for jitter

---
 configuration_flags.go | 20 ++++++++++++++++++++
 server.go              |  5 ++++-
 2 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/configuration_flags.go b/configuration_flags.go
index b1b0ddc..2444ad9 100644
--- a/configuration_flags.go
+++ b/configuration_flags.go
@@ -33,6 +33,10 @@ type Configuration struct {
 	BrokerAddress string
 	// nats connect retry
 	NatsConnectRetryInterval int
+	// NatsReconnectJitter in milliseconds
+	NatsReconnectJitter int
+	// NatsReconnectJitterTLS in seconds
+	NatsReconnectJitterTLS int
 	// The number of the profiling port
 	ProfilingPort string
 	// host and port for prometheus listener, e.g. localhost:2112
@@ -107,6 +111,8 @@ type ConfigurationFromFile struct {
 	NodeName                  *string
 	BrokerAddress             *string
 	NatsConnectRetryInterval  *int
+	NatsReconnectJitter       *int
+	NatsReconnectJitterTLS    *int
 	ProfilingPort             *string
 	PromHostAndPort           *string
 	DefaultMessageTimeout     *int
@@ -152,6 +158,8 @@ func newConfigurationDefaults() Configuration {
 		DatabaseFolder:           "./var/lib",
 		BrokerAddress:            "127.0.0.1:4222",
 		NatsConnectRetryInterval: 10,
+		NatsReconnectJitter:      100,
+		NatsReconnectJitterTLS:   1,
 		ProfilingPort:            "",
 		PromHostAndPort:          "",
 		DefaultMessageTimeout:    10,
@@ -230,6 +238,16 @@ func checkConfigValues(cf ConfigurationFromFile) Configuration {
 	} else {
 		conf.NatsConnectRetryInterval = *cf.NatsConnectRetryInterval
 	}
+	if cf.NatsReconnectJitter == nil {
+		conf.NatsReconnectJitter = cd.NatsReconnectJitter
+	} else {
+		conf.NatsReconnectJitter = *cf.NatsReconnectJitter
+	}
+	if cf.NatsReconnectJitterTLS == nil {
+		conf.NatsReconnectJitterTLS = cd.NatsReconnectJitterTLS
+	} else {
+		conf.NatsReconnectJitterTLS = *cf.NatsReconnectJitterTLS
+	}
 	if cf.ProfilingPort == nil {
 		conf.ProfilingPort = cd.ProfilingPort
 	} else {
@@ -405,6 +423,8 @@ func (c *Configuration) CheckFlags() error {
 	flag.StringVar(&c.NodeName, "nodeName", fc.NodeName, "some unique string to identify this Edge unit")
 	flag.StringVar(&c.BrokerAddress, "brokerAddress", fc.BrokerAddress, "the address of the message broker")
 	flag.IntVar(&c.NatsConnectRetryInterval, "natsConnectRetryInterval", fc.NatsConnectRetryInterval, "default nats retry connect interval in seconds.")
+	flag.IntVar(&c.NatsReconnectJitter, "natsReconnectJitter", fc.NatsReconnectJitter, "default nats ReconnectJitter interval in milliseconds.")
+	flag.IntVar(&c.NatsReconnectJitterTLS, "natsReconnectJitterTLS", fc.NatsReconnectJitterTLS, "default nats ReconnectJitterTLS interval in seconds.")
 	flag.StringVar(&c.ProfilingPort, "profilingPort", fc.ProfilingPort, "The number of the profiling port")
 	flag.StringVar(&c.PromHostAndPort, "promHostAndPort", fc.PromHostAndPort, "host and port for prometheus listener, e.g. localhost:2112")
 	flag.IntVar(&c.DefaultMessageTimeout, "defaultMessageTimeout", fc.DefaultMessageTimeout, "default message timeout in seconds. This can be overridden on the message level")
diff --git a/server.go b/server.go
index 5e91cac..c9f738f 100644
--- a/server.go
+++ b/server.go
@@ -91,7 +91,7 @@ func NewServer(c *Configuration, version string) (*server, error) {
 	for {
 		var err error
 		// Setting MaxReconnects to -1 which equals unlimited.
-		conn, err = nats.Connect(c.BrokerAddress, opt, nats.MaxReconnects(-1))
+		conn, err = nats.Connect(c.BrokerAddress, opt, nats.MaxReconnects(-1), nats.ReconnectJitter(time.Duration(c.NatsReconnectJitter)*time.Millisecond, time.Duration(c.NatsReconnectJitterTLS)*time.Second))
 		// If no servers where available, we loop and retry until succesful.
 		if err != nil {
 			log.Printf("error: could not connect, waiting %v seconds, and retrying: %v\n", c.NatsConnectRetryInterval, err)
@@ -102,6 +102,9 @@ func NewServer(c *Configuration, version string) (*server, error) {
 		break
 	}
 
+	log.Printf(" * conn.Opts.ReconnectJitterTLS: %v\n", conn.Opts.ReconnectJitterTLS)
+	log.Printf(" * conn.Opts.ReconnectJitter: %v\n", conn.Opts.ReconnectJitter)
+
 	// Prepare the connection to the  Steward socket file
 
 	// Check if socket folder exists, if not create it