From 72012516003635800a57bce535c5e34cf8f8cc7a Mon Sep 17 00:00:00 2001
From: Lou Knauer <lou.knauer@gmx.de>
Date: Fri, 4 Feb 2022 08:52:53 +0100
Subject: [PATCH] Enable basic authentication for NATS

---
 README.md       |  4 +++-
 lineprotocol.go | 13 +++++++++----
 metric-store.go |  7 +++++++
 3 files changed, 19 insertions(+), 5 deletions(-)

diff --git a/README.md b/README.md
index 791bdf4..d759fc4 100644
--- a/README.md
+++ b/README.md
@@ -76,9 +76,11 @@ All durations are specified as string that will be parsed [like this](https://pk
     - `scope`: Unused at the moment, should be something like `"node"`, `"socket"` or `"hwthread"`
 - `nats`:
     - `address`: Url of NATS.io server, example: "nats://localhost:4222"
+    - `username` and `password`: Optional, if provided use those for the connection
+    - `subscribe-to`: Where to expect the measurements to be published
 - `http-api`:
     - `address`: Address to bind to, for example `0.0.0.0:8080`
-    - `https-cert-file` and `https-key-file`: Optional, if provided enable HTTPS using those files as certificate/key.
+    - `https-cert-file` and `https-key-file`: Optional, if provided enable HTTPS using those files as certificate/key
 - `jwt-public-key`: Base64 encoded string, use this to verify requests to the HTTP API
 - `retention-on-memory`: Keep all values in memory for at least that amount of time
 - `checkpoints`:
diff --git a/lineprotocol.go b/lineprotocol.go
index 5ed8967..a1829f1 100644
--- a/lineprotocol.go
+++ b/lineprotocol.go
@@ -21,7 +21,12 @@ type Metric struct {
 // function. handleLine will be called for each line recieved via nats.
 // Send `true` through the done channel for gracefull termination.
 func ReceiveNats(conf *NatsConfig, handleLine func(dec *lineprotocol.Decoder) error, workers int, ctx context.Context) error {
-	nc, err := nats.Connect(conf.Address)
+	var opts []nats.Option
+	if conf.Username != "" && conf.Password != "" {
+		opts = append(opts, nats.UserInfo(conf.Username, conf.Password))
+	}
+
+	nc, err := nats.Connect(conf.Address, opts...)
 	if err != nil {
 		return err
 	}
@@ -48,11 +53,11 @@ func ReceiveNats(conf *NatsConfig, handleLine func(dec *lineprotocol.Decoder) er
 			}()
 		}
 
-		sub, err = nc.Subscribe("updates", func(m *nats.Msg) {
+		sub, err = nc.Subscribe(conf.SubscribeTo, func(m *nats.Msg) {
 			msgs <- m
 		})
 	} else {
-		sub, err = nc.Subscribe("updates", func(m *nats.Msg) {
+		sub, err = nc.Subscribe(conf.SubscribeTo, func(m *nats.Msg) {
 			dec := lineprotocol.NewDecoderWithBytes(m.Data)
 			if err := handleLine(dec); err != nil {
 				log.Printf("error: %s\n", err.Error())
@@ -64,7 +69,7 @@ func ReceiveNats(conf *NatsConfig, handleLine func(dec *lineprotocol.Decoder) er
 		return err
 	}
 
-	log.Printf("NATS subscription to 'updates' on '%s' established\n", conf.Address)
+	log.Printf("NATS subscription to '%s' on '%s' established\n", conf.SubscribeTo, conf.Address)
 
 	<-ctx.Done()
 	err = sub.Unsubscribe()
diff --git a/metric-store.go b/metric-store.go
index d1d16cb..e17d39f 100644
--- a/metric-store.go
+++ b/metric-store.go
@@ -39,6 +39,13 @@ type HttpConfig struct {
 type NatsConfig struct {
 	// Address of the nats server
 	Address string `json:"address"`
+
+	// Channel name
+	SubscribeTo string `json:"subscribe-to"`
+
+	// Username/Password, optional
+	Username string `json:"username"`
+	Password string `json:"password"`
 }
 
 type Config struct {