feat: bootstrap reusable GoOmni framework

config/env.go

@@ -0,0 +1,67 @@
+package config
+
+import (
+	"fmt"
+	"os"
+	"strconv"
+	"strings"
+	"time"
+)
+
+const defaultEnvPrefix = "GO_OMNI_"
+
+// LoadFromEnv loads application settings from GO_OMNI_* variables. The
+// database settings remain owned by database.ConfigFromEnv.
+func LoadFromEnv(prefix string) (Config, error) {
+	prefix = strings.TrimSpace(prefix)
+	if prefix == "" {
+		prefix = defaultEnvPrefix
+	}
+	cfg := Default()
+	cfg.Mode = envString(prefix+"MODE", cfg.Mode)
+	cfg.Address = envString(prefix+"HTTP_ADDR", cfg.Address)
+	cfg.RequestIDHeader = envString(prefix+"REQUEST_ID_HEADER", cfg.RequestIDHeader)
+	cfg.Log.Level = envString(prefix+"LOG_LEVEL", cfg.Log.Level)
+	cfg.Log.Format = envString(prefix+"LOG_FORMAT", cfg.Log.Format)
+	cfg.Log.Output = envString(prefix+"LOG_OUTPUT", cfg.Log.Output)
+	cfg.Log.File = envString(prefix+"LOG_FILE", cfg.Log.File)
+	cfg.Log.Service = envString(prefix+"SERVICE", cfg.Log.Service)
+	cfg.Log.Environment = envString(prefix+"ENVIRONMENT", cfg.Log.Environment)
+
+	var err error
+	if cfg.EnableLogger, err = envBool(prefix+"ENABLE_LOGGER", cfg.EnableLogger); err != nil {
+		return Config{}, err
+	}
+	if cfg.Log.AddSource, err = envBool(prefix+"LOG_ADD_SOURCE", cfg.Log.AddSource); err != nil {
+		return Config{}, err
+	}
+	if value := strings.TrimSpace(os.Getenv(prefix + "SHUTDOWN_TIMEOUT")); value != "" {
+		cfg.ShutdownTimeout, err = time.ParseDuration(value)
+		if err != nil {
+			return Config{}, fmt.Errorf("%sSHUTDOWN_TIMEOUT must be a duration: %w", prefix, err)
+		}
+	}
+	if err := cfg.Validate(); err != nil {
+		return Config{}, err
+	}
+	return cfg, nil
+}
+
+func envString(key, fallback string) string {
+	if value := strings.TrimSpace(os.Getenv(key)); value != "" {
+		return value
+	}
+	return fallback
+}
+
+func envBool(key string, fallback bool) (bool, error) {
+	value := strings.TrimSpace(os.Getenv(key))
+	if value == "" {
+		return fallback, nil
+	}
+	parsed, err := strconv.ParseBool(value)
+	if err != nil {
+		return false, fmt.Errorf("%s must be a boolean: %w", key, err)
+	}
+	return parsed, nil
+}