micro/config/config.go

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// Package config is an interface for dynamic configuration.
package config // import "go.unistack.org/micro/v3/config"
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import (
"context"
"errors"
"reflect"
"time"
)
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type Validator interface {
Validate() error
}
// DefaultConfig default config
var DefaultConfig = NewConfig()
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// DefaultWatcherMinInterval default min interval for poll changes
var DefaultWatcherMinInterval = 5 * time.Second
// DefaultWatcherMaxInterval default max interval for poll changes
var DefaultWatcherMaxInterval = 9 * time.Second
var (
// ErrCodecMissing is returned when codec needed and not specified
ErrCodecMissing = errors.New("codec missing")
// ErrInvalidStruct is returned when the target struct is invalid
ErrInvalidStruct = errors.New("invalid struct specified")
// ErrWatcherStopped is returned when source watcher has been stopped
ErrWatcherStopped = errors.New("watcher stopped")
// ErrWatcherNotImplemented returned when config does not implement watch
ErrWatcherNotImplemented = errors.New("watcher not implemented")
)
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// Config is an interface abstraction for dynamic configuration
type Config interface {
// Name returns name of config
Name() string
// Init the config
Init(opts ...Option) error
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// Options in the config
Options() Options
// Load config from sources
Load(context.Context, ...LoadOption) error
// Save config to sources
Save(context.Context, ...SaveOption) error
// Watch a config for changes
Watch(context.Context, ...WatchOption) (Watcher, error)
// String returns config type name
String() string
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}
// Watcher is the config watcher
type Watcher interface {
// Next blocks until update happens or error returned
Next() (map[string]interface{}, error)
// Stop stops watcher
Stop() error
}
// Load loads config from config sources
func Load(ctx context.Context, cs []Config, opts ...LoadOption) error {
var err error
for _, c := range cs {
if err = c.Init(); err != nil {
return err
}
if err = c.Load(ctx, opts...); err != nil {
return err
}
}
return nil
}
// Validate runs Validate() error func for each struct field
func Validate(ctx context.Context, cfg interface{}) error {
if cfg == nil {
return nil
}
if v, ok := cfg.(Validator); ok {
if err := v.Validate(); err != nil {
return err
}
}
sv := reflect.ValueOf(cfg)
if sv.Kind() == reflect.Ptr {
sv = sv.Elem()
}
if sv.Kind() != reflect.Struct {
return nil
}
typ := sv.Type()
for idx := 0; idx < typ.NumField(); idx++ {
fld := typ.Field(idx)
val := sv.Field(idx)
if !val.IsValid() || len(fld.PkgPath) != 0 {
continue
}
if v, ok := val.Interface().(Validator); ok {
if err := v.Validate(); err != nil {
return err
}
}
switch val.Kind() {
case reflect.Ptr:
if reflect.Indirect(val).Kind() == reflect.Struct {
if err := Validate(ctx, val.Interface()); err != nil {
return err
}
}
case reflect.Struct:
if err := Validate(ctx, val.Interface()); err != nil {
return err
}
}
}
return nil
}
var (
// DefaultAfterLoad default func that runs after config load
DefaultAfterLoad = func(ctx context.Context, c Config) error {
for _, fn := range c.Options().AfterLoad {
if err := fn(ctx, c); err != nil {
c.Options().Logger.Errorf(ctx, "%s AfterLoad err: %v", c.String(), err)
if !c.Options().AllowFail {
return err
}
}
}
return nil
}
// DefaultAfterSave default func that runs after config save
DefaultAfterSave = func(ctx context.Context, c Config) error {
for _, fn := range c.Options().AfterSave {
if err := fn(ctx, c); err != nil {
c.Options().Logger.Errorf(ctx, "%s AfterSave err: %v", c.String(), err)
if !c.Options().AllowFail {
return err
}
}
}
return nil
}
// DefaultBeforeLoad default func that runs before config load
DefaultBeforeLoad = func(ctx context.Context, c Config) error {
for _, fn := range c.Options().BeforeLoad {
if err := fn(ctx, c); err != nil {
c.Options().Logger.Errorf(ctx, "%s BeforeLoad err: %v", c.String(), err)
if !c.Options().AllowFail {
return err
}
}
}
return nil
}
// DefaultBeforeSave default func that runs befora config save
DefaultBeforeSave = func(ctx context.Context, c Config) error {
for _, fn := range c.Options().BeforeSave {
if err := fn(ctx, c); err != nil {
c.Options().Logger.Errorf(ctx, "%s BeforeSave err: %v", c.String(), err)
if !c.Options().AllowFail {
return err
}
}
}
return nil
}
)