From 5b2e5d329cd765f1f7fcc46d33bb8fe81833ce14 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Rub=C3=A9n=20Ruiz?= <ruben@ruizt.net>
Date: Sun, 21 Apr 2024 16:15:40 +0200
Subject: [PATCH] feat: make listening port configurable

---
 README.md          |  1 +
 internal/config.go | 48 +++++++++++++++++++++++++++++++++++++++-------
 internal/server.go |  5 +++--
 3 files changed, 45 insertions(+), 9 deletions(-)

diff --git a/README.md b/README.md
index 8d4c783..99b7282 100644
--- a/README.md
+++ b/README.md
@@ -69,6 +69,7 @@ You can configure `omnivore-as-rss` with environment variables or command line f
 | ------------- | ------------- |-----------|
 | OMNIVORE_AUTH_TOKEN / -t  | The API token from Omnivore  | `00000000-0000-0000-0000-000000000000` |
 | OMNIVORE_AUTH_TOKEN_FILEPATH / -tf | The filepath of the file containing the API token from Omnivore | `/run/secrets/omnivore` |
+| PORT / -p | The port where the application is going to listen (defaults to 8090) | `8090` |
 
 
 
diff --git a/internal/config.go b/internal/config.go
index 13ea6f4..4c7799e 100644
--- a/internal/config.go
+++ b/internal/config.go
@@ -12,42 +12,76 @@ var Cfg Config
 
 type Config struct {
 	OmnivoreAuthToken string
+	LocalPort string
 }
 
 func InitConfig() {
-	omnivoreToken , err := getOmnivoreToken()
+	flagMap := extractFlags()
+
+	omnivoreToken , err := getOmnivoreToken(flagMap)
+	localPort := getPort(flagMap)
+
 	if err != nil {
 		log.Fatal(err)
 	}
 
 	c := Config {
 		OmnivoreAuthToken: omnivoreToken,
+		LocalPort: localPort,
 	}
 
 	Cfg = c
 }
 
-func getOmnivoreToken() (string, error) {
-	var omnivoreTokenFlag string
-	var secretFilePathFlag string
+func extractFlags() map[string]string {
+	flagMap := map[string] string {}
 
-	flag.StringVar(&omnivoreTokenFlag, "t", "" , "the Omnivore API token")
-	flag.StringVar(&secretFilePathFlag, "tf", "" , "the path to the file with the Omnivore API Token")
+	var omnivoreToken string
+	var secretFilePath string
+	var port string
 
+	flag.StringVar(&omnivoreToken, "t", "" , "the Omnivore API token")
+	flag.StringVar(&secretFilePath, "tf", "" , "the path to the file with the Omnivore API Token")
+	flag.StringVar(&port, "p", "" , "the port where the service is going to listen")
 	flag.Parse()
 
+	flagMap["t"] = omnivoreToken
+	flagMap["tf"] = secretFilePath
+	flagMap["p"] = port
+
+	return flagMap
+}
+
+func getPort(flagMap map[string] string) string {
+	port := flagMap["p"]
+
+	if port == "" {
+		port = os.Getenv("PORT")
+		if port == "" {
+			port = "8090"
+		}
+	}
+
+	return port
+}
+
+func getOmnivoreToken(flagMap map[string]string) (string, error) {
+
+	omnivoreTokenFlag := flagMap["t"]
+
 	omnivoreToken := os.Getenv("OMNIVORE_AUTH_TOKEN")
 	if omnivoreToken == "" {
 		omnivoreToken = omnivoreTokenFlag
 	}
 
+	secretFilePathFlag := flagMap["tf"]
 	secretFilePath := os.Getenv("OMNIVORE_AUTH_TOKEN_FILEPATH")
 	if secretFilePath == "" {
 		secretFilePath = secretFilePathFlag
 	}
 
 	if omnivoreToken != "" {
-		log.Println("Reading secret from env var")
+		log.Println("Reading secret from env var or flag")
 		return omnivoreToken, nil
 	} else if secretFilePath != "" {
 		log.Println("Reading secret from file")
diff --git a/internal/server.go b/internal/server.go
index bc1b87d..5d4501f 100644
--- a/internal/server.go
+++ b/internal/server.go
@@ -9,8 +9,9 @@ import (
 
 func Serve() {
 	http.HandleFunc("/rss", rss)
-	log.Println("Starting web server: listening at port 8090")
-	http.ListenAndServe(":8090", nil)
+	localPort := Cfg.LocalPort
+	log.Println("Starting web server: listening at port ", localPort)
+	http.ListenAndServe(":" + localPort, nil)
 }
 
 func rss(w http.ResponseWriter, req *http.Request) {