CUB-127: implement Control Center CRUD API in Go

go-backend/internal/config/config.go

@@ -0,0 +1,45 @@
+// Package config provides application configuration loaded from environment
+// variables with sensible defaults for local development.
+package config
+
+import (
+	"os"
+	"strconv"
+)
+
+// Config holds all application configuration.
+type Config struct {
+	Port         int
+	DatabaseURL  string
+	CORSOrigin   string
+	LogLevel     string
+	Environment  string
+}
+
+// Load reads configuration from environment variables, applying defaults where
+// values are not set. All secrets come from the environment — nothing is hardcoded.
+func Load() *Config {
+	return &Config{
+		Port:        getEnvInt("PORT", 8080),
+		DatabaseURL: getEnv("DATABASE_URL", "postgres://controlcenter:controlcenter@localhost:5432/controlcenter?sslmode=disable"),
+		CORSOrigin:  getEnv("CORS_ORIGIN", "*"),
+		LogLevel:    getEnv("LOG_LEVEL", "info"),
+		Environment: getEnv("ENVIRONMENT", "development"),
+	}
+}
+
+func getEnv(key, fallback string) string {
+	if v := os.Getenv(key); v != "" {
+		return v
+	}
+	return fallback
+}
+
+func getEnvInt(key string, fallback int) int {
+	if v := os.Getenv(key); v != "" {
+		if i, err := strconv.Atoi(v); err == nil {
+			return i
+		}
+	}
+	return fallback
+}