Config Package

pkg/config/manager.go

@@ -0,0 +1,168 @@
+package config
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/spf13/viper"
+)
+
+// Manager handles configuration loading from multiple sources
+type Manager struct {
+	v *viper.Viper
+}
+
+// NewManager creates a new configuration manager with defaults
+func NewManager() *Manager {
+	v := viper.New()
+
+	// Set configuration file settings
+	v.SetConfigName("config")
+	v.SetConfigType("yaml")
+	v.AddConfigPath(".")
+	v.AddConfigPath("./config")
+	v.AddConfigPath("/etc/resolvespec")
+	v.AddConfigPath("$HOME/.resolvespec")
+
+	// Enable environment variable support
+	v.SetEnvPrefix("RESOLVESPEC")
+	v.SetEnvKeyReplacer(strings.NewReplacer(".", "_"))
+	v.AutomaticEnv()
+
+	// Set default values
+	setDefaults(v)
+
+	return &Manager{v: v}
+}
+
+// NewManagerWithOptions creates a new configuration manager with custom options
+func NewManagerWithOptions(opts ...Option) *Manager {
+	m := NewManager()
+	for _, opt := range opts {
+		opt(m)
+	}
+	return m
+}
+
+// Option is a functional option for configuring the Manager
+type Option func(*Manager)
+
+// WithConfigFile sets a specific config file path
+func WithConfigFile(path string) Option {
+	return func(m *Manager) {
+		m.v.SetConfigFile(path)
+	}
+}
+
+// WithConfigName sets the config file name (without extension)
+func WithConfigName(name string) Option {
+	return func(m *Manager) {
+		m.v.SetConfigName(name)
+	}
+}
+
+// WithConfigPath adds a path to search for config files
+func WithConfigPath(path string) Option {
+	return func(m *Manager) {
+		m.v.AddConfigPath(path)
+	}
+}
+
+// WithEnvPrefix sets the environment variable prefix
+func WithEnvPrefix(prefix string) Option {
+	return func(m *Manager) {
+		m.v.SetEnvPrefix(prefix)
+	}
+}
+
+// Load attempts to load configuration from file and environment
+func (m *Manager) Load() error {
+	// Try to read config file (not an error if it doesn't exist)
+	if err := m.v.ReadInConfig(); err != nil {
+		if _, ok := err.(viper.ConfigFileNotFoundError); !ok {
+			return fmt.Errorf("error reading config file: %w", err)
+		}
+		// Config file not found; will rely on defaults and env vars
+	}
+
+	return nil
+}
+
+// GetConfig returns the complete configuration
+func (m *Manager) GetConfig() (*Config, error) {
+	var cfg Config
+	if err := m.v.Unmarshal(&cfg); err != nil {
+		return nil, fmt.Errorf("failed to unmarshal config: %w", err)
+	}
+	return &cfg, nil
+}
+
+// Get returns a configuration value by key
+func (m *Manager) Get(key string) interface{} {
+	return m.v.Get(key)
+}
+
+// GetString returns a string configuration value
+func (m *Manager) GetString(key string) string {
+	return m.v.GetString(key)
+}
+
+// GetInt returns an int configuration value
+func (m *Manager) GetInt(key string) int {
+	return m.v.GetInt(key)
+}
+
+// GetBool returns a bool configuration value
+func (m *Manager) GetBool(key string) bool {
+	return m.v.GetBool(key)
+}
+
+// Set sets a configuration value
+func (m *Manager) Set(key string, value interface{}) {
+	m.v.Set(key, value)
+}
+
+// setDefaults sets default configuration values
+func setDefaults(v *viper.Viper) {
+	// Server defaults
+	v.SetDefault("server.addr", ":8080")
+	v.SetDefault("server.shutdown_timeout", "30s")
+	v.SetDefault("server.drain_timeout", "25s")
+	v.SetDefault("server.read_timeout", "10s")
+	v.SetDefault("server.write_timeout", "10s")
+	v.SetDefault("server.idle_timeout", "120s")
+
+	// Tracing defaults
+	v.SetDefault("tracing.enabled", false)
+	v.SetDefault("tracing.service_name", "resolvespec")
+	v.SetDefault("tracing.service_version", "1.0.0")
+	v.SetDefault("tracing.endpoint", "")
+
+	// Cache defaults
+	v.SetDefault("cache.provider", "memory")
+	v.SetDefault("cache.redis.host", "localhost")
+	v.SetDefault("cache.redis.port", 6379)
+	v.SetDefault("cache.redis.password", "")
+	v.SetDefault("cache.redis.db", 0)
+	v.SetDefault("cache.memcache.servers", []string{"localhost:11211"})
+	v.SetDefault("cache.memcache.max_idle_conns", 10)
+	v.SetDefault("cache.memcache.timeout", "100ms")
+
+	// Logger defaults
+	v.SetDefault("logger.dev", false)
+	v.SetDefault("logger.path", "")
+
+	// Middleware defaults
+	v.SetDefault("middleware.rate_limit_rps", 100.0)
+	v.SetDefault("middleware.rate_limit_burst", 200)
+	v.SetDefault("middleware.max_request_size", 10485760) // 10MB
+
+	// CORS defaults
+	v.SetDefault("cors.allowed_origins", []string{"*"})
+	v.SetDefault("cors.allowed_methods", []string{"GET", "POST", "PUT", "DELETE", "OPTIONS"})
+	v.SetDefault("cors.allowed_headers", []string{"*"})
+	v.SetDefault("cors.max_age", 3600)
+
+	// Database defaults
+	v.SetDefault("database.url", "")
+}