Add support env variables in config file #143

cmd/app/app.go

@@ -2,6 +2,7 @@ package app
 
 import (
 	"flag"
+	"github.com/AlexxIT/go2rtc/pkg/shell"
 	"github.com/rs/zerolog"
 	"github.com/rs/zerolog/log"
 	"gopkg.in/yaml.v3"
@@ -30,6 +31,8 @@ func Init() {
 	}
 
 	if data != nil {
+		data = []byte(shell.ReplaceEnvVars(string(data)))
+
 		if err := yaml.Unmarshal(data, &cfg); err != nil {
 			println("ERROR: " + err.Error())
 		}

pkg/shell/env.go

@@ -0,0 +1,31 @@
+package shell
+
+import (
+	"os"
+	"regexp"
+	"strings"
+)
+
+func ReplaceEnvVars(text string) string {
+	re := regexp.MustCompile(`\${([^}{]+)}`)
+	return re.ReplaceAllStringFunc(text, func(match string) string {
+		key := match[2 : len(match)-1]
+
+		var def string
+		i := strings.IndexByte(key, ':')
+		if i > 0 {
+			key, def = key[:i], key[i+1:]
+		}
+
+		value, exists := os.LookupEnv(key)
+		if exists {
+			return value
+		}
+
+		if def != "" {
+			return def
+		}
+
+		return match
+	})
+}