Config Package

2026-01-02 18:04:25 +00:00 · 2025-12-09 09:19:56 +02:00
parent 659b2925e4
commit 1baa0af0ac
12 changed files with 944 additions and 163 deletions
--- a/pkg/config/README.md
+++ b/pkg/config/README.md
@@ -0,0 +1,291 @@
+# ResolveSpec Configuration System
+
+A centralized configuration system with support for multiple configuration sources: config files (YAML, TOML, JSON), environment variables, and programmatic configuration.
+
+## Features
+
+- **Multiple Config Sources**: Config files, environment variables, and code
+- **Priority Order**: Environment variables > Config file > Defaults
+- **Multiple Formats**: YAML, TOML, JSON supported
+- **Type Safety**: Strongly-typed configuration structs
+- **Sensible Defaults**: Works out of the box with reasonable defaults
+
+## Quick Start
+
+### Basic Usage
+
+```go
+import "github.com/heinhel/ResolveSpec/pkg/config"
+
+// Create a new config manager
+mgr := config.NewManager()
+
+// Load configuration from file and environment
+if err := mgr.Load(); err != nil {
+    log.Fatal(err)
+}
+
+// Get the complete configuration
+cfg, err := mgr.GetConfig()
+if err != nil {
+    log.Fatal(err)
+}
+
+// Use the configuration
+fmt.Println("Server address:", cfg.Server.Addr)
+```
+
+### Custom Configuration Paths
+
+```go
+mgr := config.NewManagerWithOptions(
+    config.WithConfigFile("/path/to/config.yaml"),
+    config.WithEnvPrefix("MYAPP"),
+)
+```
+
+## Configuration Sources
+
+### 1. Config Files
+
+Place a `config.yaml` file in one of these locations:
+- Current directory (`.`)
+- `./config/`
+- `/etc/resolvespec/`
+- `$HOME/.resolvespec/`
+
+Example `config.yaml`:
+
+```yaml
+server:
+  addr: ":8080"
+  shutdown_timeout: 30s
+
+tracing:
+  enabled: true
+  service_name: "my-service"
+
+cache:
+  provider: "redis"
+  redis:
+    host: "localhost"
+    port: 6379
+```
+
+### 2. Environment Variables
+
+All configuration can be set via environment variables with the `RESOLVESPEC_` prefix:
+
+```bash
+export RESOLVESPEC_SERVER_ADDR=":9090"
+export RESOLVESPEC_TRACING_ENABLED=true
+export RESOLVESPEC_CACHE_PROVIDER=redis
+export RESOLVESPEC_CACHE_REDIS_HOST=localhost
+```
+
+Nested configuration uses underscores:
+- `server.addr` → `RESOLVESPEC_SERVER_ADDR`
+- `cache.redis.host` → `RESOLVESPEC_CACHE_REDIS_HOST`
+
+### 3. Programmatic Configuration
+
+```go
+mgr := config.NewManager()
+mgr.Set("server.addr", ":9090")
+mgr.Set("tracing.enabled", true)
+
+cfg, _ := mgr.GetConfig()
+```
+
+## Configuration Options
+
+### Server Configuration
+
+```yaml
+server:
+  addr: ":8080"              # Server address
+  shutdown_timeout: 30s       # Graceful shutdown timeout
+  drain_timeout: 25s          # Connection drain timeout
+  read_timeout: 10s           # HTTP read timeout
+  write_timeout: 10s          # HTTP write timeout
+  idle_timeout: 120s          # HTTP idle timeout
+```
+
+### Tracing Configuration
+
+```yaml
+tracing:
+  enabled: false                                  # Enable/disable tracing
+  service_name: "resolvespec"                     # Service name
+  service_version: "1.0.0"                        # Service version
+  endpoint: "http://localhost:4318/v1/traces"     # OTLP endpoint
+```
+
+### Cache Configuration
+
+```yaml
+cache:
+  provider: "memory"  # Options: memory, redis, memcache
+
+  redis:
+    host: "localhost"
+    port: 6379
+    password: ""
+    db: 0
+
+  memcache:
+    servers:
+      - "localhost:11211"
+    max_idle_conns: 10
+    timeout: 100ms
+```
+
+### Logger Configuration
+
+```yaml
+logger:
+  dev: false    # Development mode (human-readable output)
+  path: ""      # Log file path (empty = stdout)
+```
+
+### Middleware Configuration
+
+```yaml
+middleware:
+  rate_limit_rps: 100.0       # Requests per second
+  rate_limit_burst: 200        # Burst size
+  max_request_size: 10485760   # Max request size in bytes (10MB)
+```
+
+### CORS Configuration
+
+```yaml
+cors:
+  allowed_origins:
+    - "*"
+  allowed_methods:
+    - "GET"
+    - "POST"
+    - "PUT"
+    - "DELETE"
+    - "OPTIONS"
+  allowed_headers:
+    - "*"
+  max_age: 3600
+```
+
+### Database Configuration
+
+```yaml
+database:
+  url: "host=localhost user=postgres password=postgres dbname=mydb port=5432 sslmode=disable"
+```
+
+## Priority and Overrides
+
+Configuration sources are applied in this order (highest priority first):
+
+1. **Environment Variables** (highest priority)
+2. **Config File**
+3. **Defaults** (lowest priority)
+
+This allows you to:
+- Set defaults in code
+- Override with a config file
+- Override specific values with environment variables
+
+## Examples
+
+### Production Setup
+
+```yaml
+# config.yaml
+server:
+  addr: ":8080"
+
+tracing:
+  enabled: true
+  service_name: "myapi"
+  endpoint: "http://jaeger:4318/v1/traces"
+
+cache:
+  provider: "redis"
+  redis:
+    host: "redis"
+    port: 6379
+    password: "${REDIS_PASSWORD}"
+
+logger:
+  dev: false
+  path: "/var/log/myapi/app.log"
+```
+
+### Development Setup
+
+```bash
+# Use environment variables for development
+export RESOLVESPEC_LOGGER_DEV=true
+export RESOLVESPEC_TRACING_ENABLED=false
+export RESOLVESPEC_CACHE_PROVIDER=memory
+```
+
+### Testing Setup
+
+```go
+// Override config for tests
+mgr := config.NewManager()
+mgr.Set("cache.provider", "memory")
+mgr.Set("database.url", testDBURL)
+
+cfg, _ := mgr.GetConfig()
+```
+
+## Best Practices
+
+1. **Use config files for base configuration** - Define your standard settings
+2. **Use environment variables for secrets** - Never commit passwords/tokens
+3. **Use environment variables for deployment-specific values** - Different per environment
+4. **Keep defaults sensible** - Application should work with minimal configuration
+5. **Document your configuration** - Comment your config.yaml files
+
+## Integration with ResolveSpec Components
+
+The configuration system integrates seamlessly with ResolveSpec components:
+
+```go
+cfg, _ := config.NewManager().Load().GetConfig()
+
+// Server
+srv := server.NewGracefulServer(server.Config{
+    Addr:            cfg.Server.Addr,
+    ShutdownTimeout: cfg.Server.ShutdownTimeout,
+    // ... other fields
+})
+
+// Tracing
+if cfg.Tracing.Enabled {
+    tracer := tracing.Init(tracing.Config{
+        ServiceName:    cfg.Tracing.ServiceName,
+        ServiceVersion: cfg.Tracing.ServiceVersion,
+        Endpoint:       cfg.Tracing.Endpoint,
+    })
+    defer tracer.Shutdown(context.Background())
+}
+
+// Cache
+var cacheProvider cache.Provider
+switch cfg.Cache.Provider {
+case "redis":
+    cacheProvider = cache.NewRedisProvider(cfg.Cache.Redis.Host, cfg.Cache.Redis.Port, ...)
+case "memcache":
+    cacheProvider = cache.NewMemcacheProvider(cfg.Cache.Memcache.Servers, ...)
+default:
+    cacheProvider = cache.NewMemoryProvider()
+}
+
+// Logger
+logger.Init(cfg.Logger.Dev)
+if cfg.Logger.Path != "" {
+    logger.UpdateLoggerPath(cfg.Logger.Path, cfg.Logger.Dev)
+}
+```
--- a/pkg/config/config.go
+++ b/pkg/config/config.go
@@ -0,0 +1,80 @@
+package config
+
+import "time"
+
+// Config represents the complete application configuration
+type Config struct {
+	Server     ServerConfig     `mapstructure:"server"`
+	Tracing    TracingConfig    `mapstructure:"tracing"`
+	Cache      CacheConfig      `mapstructure:"cache"`
+	Logger     LoggerConfig     `mapstructure:"logger"`
+	Middleware MiddlewareConfig `mapstructure:"middleware"`
+	CORS       CORSConfig       `mapstructure:"cors"`
+	Database   DatabaseConfig   `mapstructure:"database"`
+}
+
+// ServerConfig holds server-related configuration
+type ServerConfig struct {
+	Addr            string        `mapstructure:"addr"`
+	ShutdownTimeout time.Duration `mapstructure:"shutdown_timeout"`
+	DrainTimeout    time.Duration `mapstructure:"drain_timeout"`
+	ReadTimeout     time.Duration `mapstructure:"read_timeout"`
+	WriteTimeout    time.Duration `mapstructure:"write_timeout"`
+	IdleTimeout     time.Duration `mapstructure:"idle_timeout"`
+}
+
+// TracingConfig holds OpenTelemetry tracing configuration
+type TracingConfig struct {
+	Enabled        bool   `mapstructure:"enabled"`
+	ServiceName    string `mapstructure:"service_name"`
+	ServiceVersion string `mapstructure:"service_version"`
+	Endpoint       string `mapstructure:"endpoint"`
+}
+
+// CacheConfig holds cache provider configuration
+type CacheConfig struct {
+	Provider string         `mapstructure:"provider"` // memory, redis, memcache
+	Redis    RedisConfig    `mapstructure:"redis"`
+	Memcache MemcacheConfig `mapstructure:"memcache"`
+}
+
+// RedisConfig holds Redis-specific configuration
+type RedisConfig struct {
+	Host     string `mapstructure:"host"`
+	Port     int    `mapstructure:"port"`
+	Password string `mapstructure:"password"`
+	DB       int    `mapstructure:"db"`
+}
+
+// MemcacheConfig holds Memcache-specific configuration
+type MemcacheConfig struct {
+	Servers      []string      `mapstructure:"servers"`
+	MaxIdleConns int           `mapstructure:"max_idle_conns"`
+	Timeout      time.Duration `mapstructure:"timeout"`
+}
+
+// LoggerConfig holds logger configuration
+type LoggerConfig struct {
+	Dev  bool   `mapstructure:"dev"`
+	Path string `mapstructure:"path"`
+}
+
+// MiddlewareConfig holds middleware configuration
+type MiddlewareConfig struct {
+	RateLimitRPS   float64 `mapstructure:"rate_limit_rps"`
+	RateLimitBurst int     `mapstructure:"rate_limit_burst"`
+	MaxRequestSize int64   `mapstructure:"max_request_size"`
+}
+
+// CORSConfig holds CORS configuration
+type CORSConfig struct {
+	AllowedOrigins []string `mapstructure:"allowed_origins"`
+	AllowedMethods []string `mapstructure:"allowed_methods"`
+	AllowedHeaders []string `mapstructure:"allowed_headers"`
+	MaxAge         int      `mapstructure:"max_age"`
+}
+
+// DatabaseConfig holds database configuration (primarily for testing)
+type DatabaseConfig struct {
+	URL string `mapstructure:"url"`
+}
--- a/pkg/config/manager.go
+++ b/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", "")
+}
--- a/pkg/config/manager_test.go
+++ b/pkg/config/manager_test.go
@@ -0,0 +1,166 @@
+package config
+
+import (
+	"os"
+	"testing"
+	"time"
+)
+
+func TestNewManager(t *testing.T) {
+	mgr := NewManager()
+	if mgr == nil {
+		t.Fatal("Expected manager to be non-nil")
+	}
+
+	if mgr.v == nil {
+		t.Fatal("Expected viper instance to be non-nil")
+	}
+}
+
+func TestDefaultValues(t *testing.T) {
+	mgr := NewManager()
+	if err := mgr.Load(); err != nil {
+		t.Fatalf("Failed to load config: %v", err)
+	}
+
+	cfg, err := mgr.GetConfig()
+	if err != nil {
+		t.Fatalf("Failed to get config: %v", err)
+	}
+
+	// Test default values
+	tests := []struct {
+		name     string
+		got      interface{}
+		expected interface{}
+	}{
+		{"server.addr", cfg.Server.Addr, ":8080"},
+		{"server.shutdown_timeout", cfg.Server.ShutdownTimeout, 30 * time.Second},
+		{"tracing.enabled", cfg.Tracing.Enabled, false},
+		{"tracing.service_name", cfg.Tracing.ServiceName, "resolvespec"},
+		{"cache.provider", cfg.Cache.Provider, "memory"},
+		{"cache.redis.host", cfg.Cache.Redis.Host, "localhost"},
+		{"cache.redis.port", cfg.Cache.Redis.Port, 6379},
+		{"logger.dev", cfg.Logger.Dev, false},
+		{"middleware.rate_limit_rps", cfg.Middleware.RateLimitRPS, 100.0},
+		{"middleware.rate_limit_burst", cfg.Middleware.RateLimitBurst, 200},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if tt.got != tt.expected {
+				t.Errorf("%s: got %v, want %v", tt.name, tt.got, tt.expected)
+			}
+		})
+	}
+}
+
+func TestEnvironmentVariableOverrides(t *testing.T) {
+	// Set environment variables
+	os.Setenv("RESOLVESPEC_SERVER_ADDR", ":9090")
+	os.Setenv("RESOLVESPEC_TRACING_ENABLED", "true")
+	os.Setenv("RESOLVESPEC_CACHE_PROVIDER", "redis")
+	os.Setenv("RESOLVESPEC_LOGGER_DEV", "true")
+	defer func() {
+		os.Unsetenv("RESOLVESPEC_SERVER_ADDR")
+		os.Unsetenv("RESOLVESPEC_TRACING_ENABLED")
+		os.Unsetenv("RESOLVESPEC_CACHE_PROVIDER")
+		os.Unsetenv("RESOLVESPEC_LOGGER_DEV")
+	}()
+
+	mgr := NewManager()
+	if err := mgr.Load(); err != nil {
+		t.Fatalf("Failed to load config: %v", err)
+	}
+
+	cfg, err := mgr.GetConfig()
+	if err != nil {
+		t.Fatalf("Failed to get config: %v", err)
+	}
+
+	// Test environment variable overrides
+	tests := []struct {
+		name     string
+		got      interface{}
+		expected interface{}
+	}{
+		{"server.addr", cfg.Server.Addr, ":9090"},
+		{"tracing.enabled", cfg.Tracing.Enabled, true},
+		{"cache.provider", cfg.Cache.Provider, "redis"},
+		{"logger.dev", cfg.Logger.Dev, true},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if tt.got != tt.expected {
+				t.Errorf("%s: got %v, want %v", tt.name, tt.got, tt.expected)
+			}
+		})
+	}
+}
+
+func TestProgrammaticConfiguration(t *testing.T) {
+	mgr := NewManager()
+	mgr.Set("server.addr", ":7070")
+	mgr.Set("tracing.service_name", "test-service")
+
+	cfg, err := mgr.GetConfig()
+	if err != nil {
+		t.Fatalf("Failed to get config: %v", err)
+	}
+
+	if cfg.Server.Addr != ":7070" {
+		t.Errorf("server.addr: got %s, want :7070", cfg.Server.Addr)
+	}
+
+	if cfg.Tracing.ServiceName != "test-service" {
+		t.Errorf("tracing.service_name: got %s, want test-service", cfg.Tracing.ServiceName)
+	}
+}
+
+func TestGetterMethods(t *testing.T) {
+	mgr := NewManager()
+	mgr.Set("test.string", "value")
+	mgr.Set("test.int", 42)
+	mgr.Set("test.bool", true)
+
+	if got := mgr.GetString("test.string"); got != "value" {
+		t.Errorf("GetString: got %s, want value", got)
+	}
+
+	if got := mgr.GetInt("test.int"); got != 42 {
+		t.Errorf("GetInt: got %d, want 42", got)
+	}
+
+	if got := mgr.GetBool("test.bool"); !got {
+		t.Errorf("GetBool: got %v, want true", got)
+	}
+}
+
+func TestWithOptions(t *testing.T) {
+	mgr := NewManagerWithOptions(
+		WithEnvPrefix("MYAPP"),
+		WithConfigName("myconfig"),
+	)
+
+	if mgr == nil {
+		t.Fatal("Expected manager to be non-nil")
+	}
+
+	// Set environment variable with custom prefix
+	os.Setenv("MYAPP_SERVER_ADDR", ":5000")
+	defer os.Unsetenv("MYAPP_SERVER_ADDR")
+
+	if err := mgr.Load(); err != nil {
+		t.Fatalf("Failed to load config: %v", err)
+	}
+
+	cfg, err := mgr.GetConfig()
+	if err != nil {
+		t.Fatalf("Failed to get config: %v", err)
+	}
+
+	if cfg.Server.Addr != ":5000" {
+		t.Errorf("server.addr: got %s, want :5000", cfg.Server.Addr)
+	}
+}