API Port as an environment variable + Dockerfile added for Arm32v7 and Arm64v8

Armv7Dockerfile

@@ -0,0 +1,10 @@
+FROM arm32v7/golang:latest as builder
+
+COPY . /build/mqtt2prometheus
+WORKDIR /build/mqtt2prometheus
+RUN make static_build TARGET_FILE=/bin/mqtt2prometheus
+
+FROM arm32v7/ubuntu:latest
+WORKDIR /
+COPY --from=builder /bin/mqtt2prometheus /mqtt2prometheus
+ENTRYPOINT ["/mqtt2prometheus"]

Armv8Dockerfile

@@ -0,0 +1,10 @@
+FROM arm64v8/golang:latest as builder
+
+COPY . /build/mqtt2prometheus
+WORKDIR /build/mqtt2prometheus
+RUN make static_build TARGET_FILE=/bin/mqtt2prometheus
+
+FROM arm64v8/ubuntu:latest
+WORKDIR /
+COPY --from=builder /bin/mqtt2prometheus /mqtt2prometheus
+ENTRYPOINT ["/mqtt2prometheus"]

Readme.md

@@ -101,6 +101,10 @@ docker run -it -v "$(pwd)/config.yaml:/config.yaml"  -p  9641:9641 ghcr.io/hikhv
 Please have a look at the [latest relase](https://github.com/hikhvar/mqtt2prometheus/releases/latest) to get a stable image tag. The latest tag may break at any moment in time since latest is pushed into the registries on every git commit in the master branch. 
 
 #### Build The Image locally
+To build a docker Image for your target system you can use the Dockerfile you need. After cloning the repository:
+```bash
+docker build -t mqtt2prometheus:arm -f Armv8Dockerfile .
+```
 To build a docker container with the mqtt2prometheus exporter included run:
 
 ```bash
@@ -112,6 +116,11 @@ To run the container with a given config file:
 ```bash
 docker run -it -v "$(pwd)/config.yaml:/config.yaml"  -p 9641:9641 mqtt2prometheus:latest 
 ```
+To run the mqtt2prometheus with another port 
+
+```bash
+docker run -it -v "$(pwd)/config.yaml:/config.yaml" -e PORT=9990 -p 9990:9990 mqtt2prometheus:latest 
+```
 
 ## Configuration
 The exporter can be configured via command line and config file. 
@@ -268,6 +277,8 @@ metrics:
 ### 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.
+Also we can change the main port of MQTT2Prometheus
+by using `PORT` environment.
 
 #### Example use with Docker
 
@@ -284,6 +295,7 @@ Then load that file into the environment before starting the container:
   docker run -it \
   -e MQTT2PROM_MQTT_USER \
   -e MQTT2PROM_MQTT_PASSWORD \
+  -e PORT=9990  \
   -v "$(pwd)/examples/config.yaml:/config.yaml" \
   -p 9641:9641 \
   ghcr.io/hikhvar/mqtt2prometheus:latest

cmd/mqtt2prometheus.go

@@ -40,7 +40,7 @@ var (
 	)
 	portFlag = flag.String(
 		"listen-port",
-		"9641",
+		portgetter(),
 		"HTTP port used to expose metrics",
 	)
 	addressFlag = flag.String(
@@ -268,3 +268,12 @@ func newTLSConfig(cfg config.Config) (*tls.Config, error) {
 		Certificates:       []tls.Certificate{cert},
 	}, nil
 }
+func portgetter() string {
+	port := os.Getenv("PORT")
+	if port != "" {
+		return port
+	} else {
+		return "9641"
+	}
+
+}