implement

cmd/simple/config.go

@@ -0,0 +1,37 @@
+package main
+
+import (
+	"encoding/json"
+	"os"
+)
+
+type config struct {
+	DSN   string `json:"dsn"`
+	Topic string `json:"topic"`
+}
+
+func parseEnvConfig() (cfg config) {
+	const defaultPath = "./cli.json"
+
+	data, err := os.ReadFile(defaultPath)
+	if err != nil {
+		if !os.IsNotExist(err) {
+			panic(err.Error())
+		}
+	} else {
+		err := json.Unmarshal(data, &cfg)
+		if err != nil {
+			panic(err.Error())
+		}
+	}
+
+	if dsn := os.Getenv("SMTH_DSN"); dsn != "" {
+		cfg.DSN = dsn
+	}
+
+	if topic := os.Getenv("SMTH_TOPIC"); topic != "" {
+		cfg.Topic = topic
+	}
+
+	return cfg
+}