add example

client_example_test.go

@@ -0,0 +1,172 @@
+package config_test
+
+import (
+	"context"
+	"fmt"
+	"log"
+	"os"
+	"sync"
+	"time"
+
+	"gitoa.ru/go-4devs/config"
+	"gitoa.ru/go-4devs/config/provider/arg"
+	"gitoa.ru/go-4devs/config/provider/env"
+	"gitoa.ru/go-4devs/config/provider/watcher"
+	"gitoa.ru/go-4devs/config/test"
+)
+
+func ExampleClient_Value() {
+	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", "--host=gitoa.ru"}
+
+	// read json config
+
+	config, err := config.New(
+		arg.New(),
+		env.New(test.Namespace, test.AppName),
+	)
+	if err != nil {
+		log.Print(err)
+
+		return
+	}
+
+	port, err := config.Value(ctx, "listen")
+	if err != nil {
+		log.Print("listen", err)
+
+		return
+	}
+
+	hostValue, err := config.Value(ctx, "host")
+	if err != nil {
+		log.Print("host ", err)
+
+		return
+	}
+
+	fmt.Printf("listen from env: %d\n", port.Int())
+	fmt.Printf("replace env host by args: %v\n", hostValue.String())
+	// Output:
+	// listen from env: 8080
+	// replace env host by args: gitoa.ru
+}
+
+func ExampleClient_Watch() {
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	_ = os.Setenv("FDEVS_CONFIG_EXAMPLE_ENABLE", "true")
+
+	watcher, err := config.New(
+		watcher.New(time.Microsecond, env.New(test.Namespace, test.AppName)),
+	)
+	if err != nil {
+		log.Print(err)
+
+		return
+	}
+
+	wg := sync.WaitGroup{}
+	wg.Add(1)
+
+	err = watcher.Watch(ctx, func(ctx context.Context, oldVar, newVar config.Value) error {
+		fmt.Println("update example_enable old: ", oldVar.Bool(), " new:", newVar.Bool())
+		wg.Done()
+		return nil
+	}, "example_enable")
+	if err != nil {
+		log.Print(err)
+
+		return
+	}
+
+	_ = os.Setenv("FDEVS_CONFIG_EXAMPLE_ENABLE", "false")
+
+	err = watcher.Watch(ctx, func(ctx context.Context, oldVar, newVar config.Value) error {
+		fmt.Println("update example_db_dsn old: ", oldVar.String(), " new:", newVar.String())
+		wg.Done()
+		return nil
+	}, "example_db_dsn")
+	if err != nil {
+		log.Print(err)
+
+		return
+	}
+
+	wg.Wait()
+
+	// Output:
+	// update example_enable old:  true  new: false
+}
+
+func ExampleClient_Value_factory() {
+	ctx := context.Background()
+	_ = os.Setenv("FDEVS_CONFIG_LISTEN", "8080")
+	_ = os.Setenv("FDEVS_CONFIG_HOST", "localhost")
+	_ = os.Setenv("FDEVS_GOLANG_HOST", "go.dev")
+
+	args := os.Args
+
+	defer func() {
+		os.Args = args
+	}()
+
+	os.Args = []string{"main.go", "--env=golang"}
+
+	config, err := config.New(
+		arg.New(),
+		config.Factory(func(ctx context.Context, cfg config.Provider) (config.Provider, error) {
+			val, err := cfg.Value(ctx, "env")
+			if err != nil {
+				return nil, fmt.Errorf("failed read config file:%w", err)
+			}
+
+			return env.New(test.Namespace, val.String()), nil
+		}),
+		env.New(test.Namespace, test.AppName),
+	)
+	if err != nil {
+		log.Print(err)
+
+		return
+	}
+
+	envName, err := config.Value(ctx, "env")
+	if err != nil {
+		log.Print("env ", err)
+
+		return
+	}
+
+	host, err := config.Value(ctx, "host")
+	if err != nil {
+		log.Print("host ", err)
+
+		return
+	}
+
+	listen, err := config.Value(ctx, "listen")
+	if err != nil {
+		log.Print("listen", err)
+
+		return
+	}
+
+	fmt.Printf("envName from env: %s\n", envName.String())
+	fmt.Printf("host from env with app name golang: %s\n", host.String())
+	fmt.Printf("listen from env with default app name: %s\n", listen.String())
+	// Output:
+	// envName from env: golang
+	// host from env with app name golang: go.dev
+	// listen from env with default app name: 8080
+}