config: load defaults

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

config/default_test.go

@@ -0,0 +1,66 @@
+package config_test
+
+import (
+	"context"
+	"fmt"
+	"testing"
+
+	"github.com/unistack-org/micro/v3/config"
+)
+
+type Cfg struct {
+	StringValue string `default:"string_value"`
+	IntValue    int    `default:"99"`
+}
+
+func TestDefault(t *testing.T) {
+	ctx := context.Background()
+	conf := &Cfg{}
+	blfn := func(ctx context.Context, cfg config.Config) error {
+		conf, ok := cfg.Options().Struct.(*Cfg)
+		if !ok {
+			return fmt.Errorf("failed to get Struct from options: %v", cfg.Options())
+		}
+		conf.StringValue = "before_load"
+		return nil
+	}
+	alfn := func(ctx context.Context, cfg config.Config) error {
+		conf, ok := cfg.Options().Struct.(*Cfg)
+		if !ok {
+			return fmt.Errorf("failed to get Struct from options: %v", cfg.Options())
+		}
+		conf.StringValue = "after_load"
+		return nil
+	}
+
+	cfg := config.NewConfig(config.Struct(conf), config.BeforeLoad(blfn), config.AfterLoad(alfn))
+	if err := cfg.Init(); err != nil {
+		t.Fatal(err)
+	}
+	for _, fn := range cfg.Options().BeforeLoad {
+		if err := fn(ctx, cfg); err != nil {
+			t.Fatal(err)
+		}
+	}
+	if conf.StringValue != "before_load" {
+		t.Fatal("BeforeLoad option not working")
+	}
+
+	if err := cfg.Load(ctx); err != nil {
+		t.Fatal(err)
+	}
+
+	if conf.StringValue != "string_value" || conf.IntValue != 99 {
+		t.Fatalf("load failed: %#+v", conf)
+	}
+
+	for _, fn := range cfg.Options().AfterLoad {
+		if err := fn(ctx, cfg); err != nil {
+			t.Fatal(err)
+		}
+	}
+	if conf.StringValue != "after_load" {
+		t.Fatal("AfterLoad option not working")
+	}
+
+}