refactor: better configuration logic

cmd/httb/main.go

@@ -2,8 +2,10 @@ package main
 
 import (
 	_ "embed"
+	"fmt"
 	"github.com/marvinjwendt/httb/internal/pkg/service"
 	"log/slog"
+	"os"
 
 	"github.com/marvinjwendt/httb/internal/pkg/config"
 )
@@ -12,14 +14,23 @@ var cfg *config.Config
 
 func init() {
 	// Init config
-	env := config.ReadEnv()
-	cfg = config.New(env)
+	var err error
+	cfg, err = config.LoadConfig()
+	if err != nil {
+		_, _ = fmt.Fprintf(os.Stderr, "failed to load config: %v\n", err)
+		os.Exit(1)
+	}
 
 	// Init logger
-	slog.SetDefault(cfg.Logger)
+	logger, err := cfg.SetupLogger()
+	if err != nil {
+		_, _ = fmt.Fprintf(os.Stderr, "failed to setup logger: %v\n", err)
+		os.Exit(1)
+	}
+	slog.SetDefault(logger)
 
 	// Print config in debug mode
-	slog.Debug("configuration", "environment", env)
+	slog.Debug("configuration", "environment", cfg)
 }
 
 func main() {

go.mod

@@ -41,6 +41,7 @@ require (
 	github.com/breml/errchkjson v0.4.0 // indirect
 	github.com/butuzov/ireturn v0.3.0 // indirect
 	github.com/butuzov/mirror v1.2.0 // indirect
+	github.com/caarlos0/env/v11 v11.3.1 // indirect
 	github.com/catenacyber/perfsprint v0.7.1 // indirect
 	github.com/ccojocar/zxcvbn-go v1.0.2 // indirect
 	github.com/cespare/xxhash/v2 v2.1.2 // indirect

go.sum

@@ -108,6 +108,8 @@ github.com/butuzov/ireturn v0.3.0 h1:hTjMqWw3y5JC3kpnC5vXmFJAWI/m31jaCYQqzkS6PL0
 github.com/butuzov/ireturn v0.3.0/go.mod h1:A09nIiwiqzN/IoVo9ogpa0Hzi9fex1kd9PSD6edP5ZA=
 github.com/butuzov/mirror v1.2.0 h1:9YVK1qIjNspaqWutSv8gsge2e/Xpq1eqEkslEUHy5cs=
 github.com/butuzov/mirror v1.2.0/go.mod h1:DqZZDtzm42wIAIyHXeN8W/qb1EPlb9Qn/if9icBOpdQ=
+github.com/caarlos0/env/v11 v11.3.1 h1:cArPWC15hWmEt+gWk7YBi7lEXTXCvpaSdCiZE2X5mCA=
+github.com/caarlos0/env/v11 v11.3.1/go.mod h1:qupehSf/Y0TUTsxKywqRt/vJjN5nz6vauiYEUUr8P4U=
 github.com/catenacyber/perfsprint v0.7.1 h1:PGW5G/Kxn+YrN04cRAZKC+ZuvlVwolYMrIyyTJ/rMmc=
 github.com/catenacyber/perfsprint v0.7.1/go.mod h1:/wclWYompEyjUD2FuIIDVKNkqz7IgBIWXIH3V0Zol50=
 github.com/ccojocar/zxcvbn-go v1.0.2 h1:na/czXU8RrhXO4EZme6eQJLR4PzcGsahsBOAwU6I3Vg=

internal/pkg/config/config.go

@@ -2,121 +2,64 @@ package config
 
 import (
 	"fmt"
+	"github.com/caarlos0/env/v11"
 	"log/slog"
 	"os"
 	"strings"
 	"time"
 )
 
-var hasError bool
-
-type Env struct {
-	LogLevel  string
-	LogFormat string
-	Addr      string
-	Timeout   string
-}
-
-func (e *Env) String() string {
-	return fmt.Sprintf("%+v", *e)
-}
-
+// Config holds application configuration.
 type Config struct {
-	// Logger is the slog logger to use
-	Logger *slog.Logger
-
-	// Addr is the address to listen on
-	Addr string `json:"addr"`
-
-	// Timeout is the timeout for the http server
-	Timeout time.Duration `json:"timeout"`
-}
-
-// ReadEnv reads the environment variables and returns an Env struct.
-func ReadEnv() *Env {
-	return &Env{
-		LogLevel:  getEnv("LOG_LEVEL", "info"),
-		LogFormat: getEnv("LOG_FORMAT", "logfmt"),
-		Addr:      getEnv("ADDR", ":8080"),
-		Timeout:   getEnv("TIMEOUT", "2m"),
-	}
+	LogLevel  string        `env:"LOG_LEVEL" envDefault:"info"`
+	LogFormat string        `env:"LOG_FORMAT" envDefault:"logfmt"`
+	Addr      string        `env:"ADDR" envDefault:":8080"`
+	Timeout   time.Duration `env:"TIMEOUT" envDefault:"2m"`
 }
 
-// New reads the configuration from the environment variables and returns a Config and Env struct.
-func New(env *Env) *Config {
-	cfg := &Config{
-		Logger:  parseLogger(env.LogLevel, env.LogFormat),
-		Addr:    env.Addr,
-		Timeout: parseTimeout(env.Timeout),
-	}
-
-	if hasError {
-		os.Exit(1)
+// LoadConfig reads the environment variables and returns a Config struct.
+func LoadConfig() (*Config, error) {
+	cfg := &Config{}
+	if err := env.Parse(cfg); err != nil {
+		return nil, fmt.Errorf("failed to parse environment variables: %w", err)
 	}
-
-	return cfg
+	return cfg, nil
 }
 
-func parseTimeout(timeout string) time.Duration {
-	d, err := time.ParseDuration(timeout)
+// SetupLogger initializes the slog.Logger based on the config.
+func (cfg *Config) SetupLogger() (*slog.Logger, error) {
+	format := strings.ToLower(cfg.LogFormat)
+	level, err := parseLogLevel(cfg.LogLevel)
 	if err != nil {
-		configError("invalid timeout", "timeout", timeout)
+		return nil, err
 	}
 
-	return d
-}
-
-func parseLogger(level, format string) *slog.Logger {
-	format = strings.ToLower(format)
-
 	var handler slog.Handler
 
 	switch format {
 	case "json":
-		handler = slog.NewJSONHandler(os.Stdout, &slog.HandlerOptions{Level: parseLogLevel(level)})
+		handler = slog.NewJSONHandler(os.Stdout, &slog.HandlerOptions{Level: level})
 	case "logfmt", "text":
-		handler = slog.NewTextHandler(os.Stdout, &slog.HandlerOptions{Level: parseLogLevel(level)})
+		handler = slog.NewTextHandler(os.Stdout, &slog.HandlerOptions{Level: level})
 	default:
-		configError("invalid log format", "log_format", format)
+		return nil, fmt.Errorf("invalid log format: %s", format)
 	}
 
-	return slog.New(handler)
+	return slog.New(handler), nil
 }
 
-// parseLogLevel parses the log level from the environment variable and returns the corresponding slog.Level.
-// If the level is invalid, it logs an error and returns slog.LevelInfo.
-// Possible values are: debug, info, warn, error - default is info.
-func parseLogLevel(level string) slog.Level {
-	level = strings.ToLower(level)
-
-	switch level {
+// parseLogLevel converts a string to a slog.Level, returning an error if invalid.
+func parseLogLevel(level string) (slog.Level, error) {
+	switch strings.ToLower(level) {
 	case "debug":
-		return slog.LevelDebug
+		return slog.LevelDebug, nil
 	case "info":
-		return slog.LevelInfo
+		return slog.LevelInfo, nil
 	case "warn":
-		return slog.LevelWarn
+		return slog.LevelWarn, nil
 	case "error":
-		return slog.LevelError
+		return slog.LevelError, nil
 	default:
-		configError("invalid log level", "log_level", level)
-		return slog.LevelInfo
-	}
-}
-
-// error logs an error message and sets the hasError flag to true, which will cause the program to exit with a non-zero exit code.
-func configError(msg string, args ...any) {
-	msg = "in config: " + msg
-	slog.Error(msg, args...)
-
-	hasError = true
-}
-
-// getEnv returns the value of a given environment variable, or the defined default value.
-func getEnv(key, def string) string {
-	if val := os.Getenv(key); val != "" {
-		return val
+		return slog.LevelInfo, fmt.Errorf("invalid log level: %s", level)
 	}
-
-	return def
 }

internal/pkg/service/server.go

@@ -17,7 +17,7 @@ func (s Service) Start() error {
 	e.HidePort = true
 
 	// Echo middlewares
-	e.Use(slogecho.New(s.config.Logger))
+	e.Use(slogecho.New(slog.Default()))
 	e.Use(middleware.Recover())
 	e.Use(middleware.CORS())