From c26207fff6b57e15e6a70df796f9562861202a87 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Valdimar=20Bj=C3=B6rn=20=C3=81sgeirsson?=
 <vrioniavas@gmail.com>
Date: Mon, 13 Sep 2021 16:57:12 +0000
Subject: [PATCH 1/2] Read mqtt user and password from environment

Environment variables override config variables, if they exist
---
 cmd/mqtt2prometheus.go | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/cmd/mqtt2prometheus.go b/cmd/mqtt2prometheus.go
index 17da069..bfcad1f 100644
--- a/cmd/mqtt2prometheus.go
+++ b/cmd/mqtt2prometheus.go
@@ -79,6 +79,17 @@ func main() {
 	if err != nil {
 		logger.Fatal("Could not load config", zap.Error(err))
 	}
+
+	mqtt_user := os.Getenv("MQTT2PROM_MQTT_USER")
+	mqtt_password := os.Getenv("MQTT2PROM_MQTT_PASSWORD")
+
+	if mqtt_user != "" {
+		cfg.MQTT.User = mqtt_user
+	}
+	if mqtt_password != "" {
+		cfg.MQTT.Password = mqtt_password
+	}
+
 	mqttClientOptions := mqtt.NewClientOptions()
 	mqttClientOptions.AddBroker(cfg.MQTT.Server).SetCleanSession(true)
 	mqttClientOptions.SetAutoReconnect(true)

From 83413b19e29c443eb73031a2955ee40c16dd335d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Valdimar=20Bj=C3=B6rn=20=C3=81sgeirsson?=
 <vrioniavas@gmail.com>
Date: Mon, 20 Sep 2021 13:12:15 +0000
Subject: [PATCH 2/2] Update readme for env vars

Describe how to supply MQTT username and password via environment variables.
---
 Readme.md | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/Readme.md b/Readme.md
index 1400700..f43d2de 100644
--- a/Readme.md
+++ b/Readme.md
@@ -179,6 +179,30 @@ metrics:
       error_value: 1      
 ```
 
+### Environment Variables
+
+Having the MQTT login details in the config file runs the risk of publishing them to a version control system. To avoid this, you can supply these parameters via environment variables. MQTT2Prometheus will look for `MQTT2PROM_MQTT_USER` and `MQTT2PROM_MQTT_PASSWORD` in the local environment and load them on startup.
+
+#### Example use with Docker
+
+Create a file to store your login details, for example at `~/secrets/mqtt2prom`:
+```SHELL
+#!/bin/bash
+export MQTT2PROM_MQTT_USER="myUser" 
+export MQTT2PROM_MQTT_PASSWORD="superpassword"
+```
+
+Then load that file into the environment before starting the container:
+```SHELL
+ source ~/secrets/mqtt2prom && \
+  docker run -it \
+  -e MQTT2PROM_MQTT_USER \
+  -e MQTT2PROM_MQTT_PASSWORD \
+  -v "$(pwd)/examples/config.yaml:/config.yaml" \
+  -p 9641:9641 \
+  ghcr.io/hikhvar/mqtt2prometheus:latest
+```
+
 
 ## Best Practices
 The exporter can only listen to one topic_path per instance. If you have to listen to two different topic_paths it is