first commit

client.go

@@ -0,0 +1,96 @@
+package config
+
+import (
+	"context"
+	"errors"
+	"fmt"
+)
+
+func New(namespace, appName string, providers []Provider) *Client {
+	return &Client{
+		namespace: namespace,
+		appName:   appName,
+		providers: providers,
+	}
+}
+
+type Client struct {
+	providers []Provider
+	appName   string
+	namespace string
+}
+
+func (c *Client) key(name string) Key {
+	return Key{
+		Name:      name,
+		AppName:   c.appName,
+		Namespace: c.namespace,
+	}
+}
+
+func (c *Client) Value(ctx context.Context, name string) (Value, error) {
+	variable, err := c.Variable(ctx, name)
+	if err != nil {
+		return nil, err
+	}
+
+	return variable.Value, nil
+}
+
+func (c *Client) Variable(ctx context.Context, name string) (Variable, error) {
+	var (
+		variable Variable
+		err      error
+	)
+
+	key := c.key(name)
+
+	for _, provider := range c.providers {
+		variable, err = provider.Read(ctx, key)
+		if err == nil || !errors.Is(err, ErrVariableNotFound) {
+			break
+		}
+	}
+
+	if err != nil {
+		return variable, fmt.Errorf("client failed get variable: %w", err)
+	}
+
+	return variable, nil
+}
+
+func NewWatch(namespace, appName string, providers []Provider) *WatchClient {
+	cl := WatchClient{
+		Client: New(namespace, appName, providers),
+	}
+
+	for _, provider := range providers {
+		if watch, ok := provider.(WatchProvider); ok {
+			cl.providers = append(cl.providers, watch)
+		}
+	}
+
+	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) {
+				continue
+			}
+
+			return fmt.Errorf("client: failed watch by provider %s: %w", provider.Name(), err)
+		}
+	}
+
+	return nil
+}