add configure provider by preview providers

client.go

@@ -4,14 +4,82 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"sync"
+	"sync/atomic"
 )
 
-func New(namespace, appName string, providers []Provider) *Client {
+func Must(namespace, appName string, providers ...interface{}) *Client {
-	return &Client{
+	client, err := New(namespace, appName, providers...)
+	if err != nil {
+		panic(err)
+	}
+
+	return client
+}
+
+func New(namespace, appName string, providers ...interface{}) (*Client, error) {
+	client := &Client{
 		namespace: namespace,
 		appName:   appName,
-		providers: providers,
+		providers: make([]Provider, len(providers)),
 	}
+
+	for idx, prov := range providers {
+		switch current := prov.(type) {
+		case Provider:
+			client.providers[idx] = current
+		case Factory:
+			client.providers[idx] = &provider{
+				factory: func(ctx context.Context) (Provider, error) {
+					return current(ctx, client)
+				},
+			}
+		default:
+			return nil, fmt.Errorf("provier[%d]: %w %T", idx, ErrUnknowType, prov)
+		}
+	}
+
+	return client, nil
+}
+
+type provider struct {
+	mu       sync.Mutex
+	done     uint32
+	provider Provider
+	factory  func(ctx context.Context) (Provider, error)
+}
+
+func (p *provider) init(ctx context.Context) (err error) {
+	if atomic.LoadUint32(&p.done) == 0 {
+		if !p.mu.TryLock() {
+			return fmt.Errorf("%w", ErrInitFactory)
+		}
+		defer atomic.StoreUint32(&p.done, 1)
+		defer p.mu.Unlock()
+		p.provider, err = p.factory(ctx)
+	}
+
+	return err
+}
+
+func (p *provider) Watch(ctx context.Context, key Key, callback WatchCallback) error {
+	if err := p.init(ctx); err != nil {
+		return fmt.Errorf("init read:%w", err)
+	}
+
+	if watch, ok := p.provider.(WatchProvider); ok {
+		return watch.Watch(ctx, key, callback)
+	}
+
+	return nil
+}
+
+func (p *provider) Read(ctx context.Context, key Key) (Variable, error) {
+	if err := p.init(ctx); err != nil {
+		return Variable{}, fmt.Errorf("init read:%w", err)
+	}
+
+	return p.provider.Read(ctx, key)
 }
 
 type Client struct {
@@ -47,7 +115,7 @@ func (c *Client) Variable(ctx context.Context, name string) (Variable, error) {
 
 	for _, provider := range c.providers {
 		variable, err = provider.Read(ctx, key)
-		if err == nil || !errors.Is(err, ErrVariableNotFound) {
+		if err == nil || !(errors.Is(err, ErrVariableNotFound) || errors.Is(err, ErrInitFactory)) {
 			break
 		}
 	}
@@ -59,36 +127,22 @@ func (c *Client) Variable(ctx context.Context, name string) (Variable, error) {
 	return variable, nil
 }
 
-func NewWatch(namespace, appName string, providers []Provider) *WatchClient {
+func (c *Client) Watch(ctx context.Context, name string, callback WatchCallback) error {
-	cl := WatchClient{
+	key := c.key(name)
-		Client: New(namespace, appName, providers),
-	}
 
-	for _, provider := range providers {
+	for idx, prov := range c.providers {
-		if watch, ok := provider.(WatchProvider); ok {
+		provider, ok := prov.(WatchProvider)
-			cl.providers = append(cl.providers, watch)
+		if !ok {
+			continue
 		}
-	}
 
-	return &cl
-}
-
-type WatchClient struct {
-	*Client
-	providers []WatchProvider
-}
-
-func (wc *WatchClient) Watch(ctx context.Context, name string, callback WatchCallback) error {
-	key := wc.key(name)
-
-	for _, provider := range wc.providers {
 		err := provider.Watch(ctx, key, callback)
 		if err != nil {
-			if errors.Is(err, ErrVariableNotFound) {
+			if errors.Is(err, ErrVariableNotFound) || errors.Is(err, ErrInitFactory) {
 				continue
 			}
 
-			return fmt.Errorf("client: failed watch by provider %s: %w", provider.Name(), err)
+			return fmt.Errorf("client: failed watch by provider[%d]: %w", idx, err)
 		}
 	}
 

client_example_test.go

@@ -19,7 +19,7 @@ import (
 	"gitoa.ru/go-4devs/config/test"
 )
 
-func ExampleNew() {
+func ExampleClient_Value() {
 	ctx := context.Background()
 	_ = os.Setenv("FDEVS_CONFIG_LISTEN", "8080")
 	_ = os.Setenv("FDEVS_CONFIG_HOST", "localhost")
@@ -51,14 +51,18 @@ func ExampleNew() {
 	// read json config
 	jsonConfig := test.ReadFile("config.json")
 
-	providers := []config.Provider{
+	config, err := config.New(test.Namespace, test.AppName,
 		arg.New(),
 		env.New(),
 		etcd.NewProvider(etcdClient),
 		vault.NewSecretKV2(vaultClient),
 		json.New(jsonConfig),
+	)
+	if err != nil {
+		log.Print(err)
+
+		return
 	}
-	config := config.New(test.Namespace, test.AppName, providers)
 
 	dsn, err := config.Value(ctx, "example:dsn")
 	if err != nil {
@@ -120,7 +124,7 @@ func ExampleNew() {
 	// replace env host by args: gitoa.ru
 }
 
-func ExampleNewWatch() {
+func ExampleClient_Watch() {
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
 
@@ -151,12 +155,17 @@ func ExampleNewWatch() {
 		}
 	}()
 
-	providers := []config.Provider{
+	watcher, err := config.New(test.Namespace, test.AppName,
 		watcher.New(time.Microsecond, env.New()),
-		watcher.New(time.Microsecond, yaml.NewFile("test/fixture/config.yaml")),
+		watcher.New(time.Microsecond, yaml.NewWatch("test/fixture/config.yaml")),
 		etcd.NewProvider(etcdClient),
+	)
+	if err != nil {
+		log.Print(err)
+
+		return
 	}
-	watcher := config.NewWatch(test.Namespace, test.AppName, providers)
+
 	wg := sync.WaitGroup{}
 	wg.Add(2)
 
@@ -196,3 +205,90 @@ func ExampleNewWatch() {
 	// update  env  variable: FDEVS_CONFIG_EXAMPLE_ENABLE , old:  true  new: false
 	// update  etcd  variable: fdevs/config/example_db_dsn , old:  pgsql://user@pass:127.0.0.1:5432  new: mysql://localhost:5432
 }
+
+func ExampleClient_Value_factory() {
+	ctx := context.Background()
+	_ = os.Setenv("FDEVS_CONFIG_LISTEN", "8080")
+	_ = os.Setenv("FDEVS_CONFIG_HOST", "localhost")
+
+	args := os.Args
+
+	defer func() {
+		os.Args = args
+	}()
+
+	os.Args = []string{"main.go", "--config-json=config.json", "--config-yaml=test/fixture/config.yaml"}
+
+	config, err := config.New(test.Namespace, test.AppName,
+		arg.New(),
+		env.New(),
+		config.Factory(func(ctx context.Context, cfg config.ReadConfig) (config.Provider, error) {
+			val, err := cfg.Value(ctx, "config-json")
+			if err != nil {
+				return nil, fmt.Errorf("failed read config file:%w", err)
+			}
+			jsonConfig := test.ReadFile(val.String())
+
+			return json.New(jsonConfig), nil
+		}),
+		config.Factory(func(ctx context.Context, cfg config.ReadConfig) (config.Provider, error) {
+			val, err := cfg.Value(ctx, "config-yaml")
+			if err != nil {
+				return nil, fmt.Errorf("failed read config file:%w", err)
+			}
+
+			provader, err := yaml.NewFile(val.String())
+			if err != nil {
+				return nil, fmt.Errorf("failed init by file %v:%w", val.String(), err)
+			}
+
+			return provader, nil
+		}),
+	)
+	if err != nil {
+		log.Print(err)
+
+		return
+	}
+
+	port, err := config.Value(ctx, "listen")
+	if err != nil {
+		log.Print(err)
+
+		return
+	}
+
+	title, err := config.Value(ctx, "app.name.title")
+	if err != nil {
+		log.Print(err)
+
+		return
+	}
+
+	yamlTitle, err := config.Value(ctx, "app/title")
+	if err != nil {
+		log.Print(err)
+
+		return
+	}
+
+	cfgValue, err := config.Value(ctx, "cfg")
+	if err != nil {
+		log.Print(err)
+
+		return
+	}
+
+	cfg := test.Config{}
+	_ = cfgValue.Unmarshal(&cfg)
+
+	fmt.Printf("listen from env: %d\n", port.Int())
+	fmt.Printf("title from json: %v\n", title.String())
+	fmt.Printf("title from yaml: %v\n", yamlTitle.String())
+	fmt.Printf("struct from json: %+v\n", cfg)
+	// Output:
+	// listen from env: 8080
+	// title from json: config title
+	// title from yaml: yaml title
+	// struct from json: {Duration:21m0s Enabled:true}
+}

error.go

@@ -5,4 +5,6 @@ import "errors"
 var (
 	ErrVariableNotFound = errors.New("variable not found")
 	ErrInvalidValue     = errors.New("invalid value")
+	ErrUnknowType       = errors.New("unknow type")
+	ErrInitFactory      = errors.New("init factory")
 )

provider.go

@@ -4,16 +4,16 @@ import "context"
 
 type Provider interface {
 	Read(ctx context.Context, key Key) (Variable, error)
-	NamedProvider
 }
 
 type WatchCallback func(ctx context.Context, oldVar, newVar Variable)
 
 type WatchProvider interface {
 	Watch(ctx context.Context, key Key, callback WatchCallback) error
-	NamedProvider
 }
 
-type NamedProvider interface {
+type ReadConfig interface {
-	Name() string
+	Value(ctx context.Context, name string) (Value, error)
 }
+
+type Factory func(ctx context.Context, cfg ReadConfig) (Provider, error)

provider/watcher/provider.go

@@ -47,7 +47,7 @@ type Provider struct {
 func (p *Provider) Watch(ctx context.Context, key config.Key, callback config.WatchCallback) error {
 	oldVar, err := p.Provider.Read(ctx, key)
 	if err != nil {
-		return fmt.Errorf("%s: failed watch variable: %w", p.Provider.Name(), err)
+		return fmt.Errorf("failed watch variable: %w", err)
 	}
 
 	go func() {

provider/yaml/file.go

@@ -1,57 +0,0 @@
-package yaml
-
-import (
-	"context"
-	"fmt"
-	"io/ioutil"
-
-	"gitoa.ru/go-4devs/config"
-	"gopkg.in/yaml.v3"
-)
-
-func WithFileKeyFactory(f func(context.Context, config.Key) []string) FileOption {
-	return func(p *File) {
-		p.key = f
-	}
-}
-
-type FileOption func(*File)
-
-func NewFile(name string, opts ...FileOption) *File {
-	f := File{
-		file: name,
-		key:  keyFactory,
-	}
-
-	for _, opt := range opts {
-		opt(&f)
-	}
-
-	return &f
-}
-
-type File struct {
-	file string
-	key  func(context.Context, config.Key) []string
-}
-
-func (p *File) Name() string {
-	return "yaml_file"
-}
-
-func (p *File) Read(ctx context.Context, key config.Key) (config.Variable, error) {
-	in, err := ioutil.ReadFile(p.file)
-	if err != nil {
-		return config.Variable{}, fmt.Errorf("yaml_file: read error: %w", err)
-	}
-
-	var n yaml.Node
-	if err = yaml.Unmarshal(in, &n); err != nil {
-		return config.Variable{}, fmt.Errorf("yaml_file: unmarshal error: %w", err)
-	}
-
-	data := node{Node: &n}
-	k := p.key(ctx, key)
-
-	return data.read(p.Name(), k)
-}

provider/yaml/provider.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"io/ioutil"
 	"strings"
 
 	"gitoa.ru/go-4devs/config"
@@ -17,22 +18,34 @@ func keyFactory(ctx context.Context, key config.Key) []string {
 	return strings.Split(key.Name, "/")
 }
 
+func NewFile(name string, opts ...Option) (*Provider, error) {
+	in, err := ioutil.ReadFile(name)
+	if err != nil {
+		return nil, fmt.Errorf("yaml_file: read error: %w", err)
+	}
+
+	return New(in, opts...)
+}
+
 func New(yml []byte, opts ...Option) (*Provider, error) {
 	var data yaml.Node
 	if err := yaml.Unmarshal(yml, &data); err != nil {
 		return nil, fmt.Errorf("yaml: unmarshal err: %w", err)
 	}
 
+	return create(opts...).With(&data), nil
+}
+
+func create(opts ...Option) *Provider {
 	p := Provider{
-		key:  keyFactory,
+		key: keyFactory,
-		data: node{Node: &data},
 	}
 
 	for _, opt := range opts {
 		opt(&p)
 	}
 
-	return &p, nil
+	return &p
 }
 
 type Option func(*Provider)
@@ -52,6 +65,13 @@ func (p *Provider) Read(ctx context.Context, key config.Key) (config.Variable, e
 	return p.data.read(p.Name(), k)
 }
 
+func (p *Provider) With(data *yaml.Node) *Provider {
+	return &Provider{
+		key:  p.key,
+		data: node{Node: data},
+	}
+}
+
 type node struct {
 	*yaml.Node
 }

provider/yaml/watch.go

@@ -0,0 +1,42 @@
+package yaml
+
+import (
+	"context"
+	"fmt"
+	"io/ioutil"
+
+	"gitoa.ru/go-4devs/config"
+	"gopkg.in/yaml.v3"
+)
+
+func NewWatch(name string, opts ...Option) *Watch {
+	f := Watch{
+		file: name,
+		prov: create(opts...),
+	}
+
+	return &f
+}
+
+type Watch struct {
+	file string
+	prov *Provider
+}
+
+func (p *Watch) Name() string {
+	return "yaml_watch"
+}
+
+func (p *Watch) Read(ctx context.Context, key config.Key) (config.Variable, error) {
+	in, err := ioutil.ReadFile(p.file)
+	if err != nil {
+		return config.Variable{}, fmt.Errorf("yaml_file: read error: %w", err)
+	}
+
+	var n yaml.Node
+	if err = yaml.Unmarshal(in, &n); err != nil {
+		return config.Variable{}, fmt.Errorf("yaml_file: unmarshal error: %w", err)
+	}
+
+	return p.prov.With(&n).Read(ctx, key)
+}

test/fixture/config.json

@@ -11,6 +11,7 @@
     },
     "cfg": {
         "duration": 1260000000000,
-        "enabled": true
+        "enabled": true,
+        "type":"json"
     }
 }

test/fixture/config.yaml

@@ -1,4 +1,5 @@
 app:
+    title: yaml title
     name:
         var: 
             - test
@@ -10,3 +11,4 @@ time_var: "2020-01-02T15:04:05Z"
 cfg:
     duration: 21m
     enabled: true
+    type: yaml