add doc for run about func() []any (#41)

gcp/gcp_test.go

@@ -43,11 +43,7 @@ func TestOptions(t *testing.T) {
 		{
 			description: "with options",
 			opts: []gcp.Option{
-				gcp.WithOptions(func() []gcp.Option {
-					return []gcp.Option{
-						gcp.WithProject("project"),
-					}
-				}),
+				gcp.WithProject("project"),
 			},
 			assertion: func(t *testing.T, opts []any) {
 				t.Helper()

gcp/option.go

@@ -67,17 +67,6 @@ func WithMetric(opts ...otlpmetricgrpc.Option) Option {
 	}
 }
 
-// WithOptions provides the function which returns multiple Option(s).
-// It's useful while the Option needs to read configuration from config,
-// since it defers the creation of Option(s) until the config is loaded.
-func WithOptions(f func() []Option) Option {
-	return func(options *options) {
-		for _, opt := range f() {
-			opt(options)
-		}
-	}
-}
-
 type (
 	// Option configures the GCP runtime with specific options.
 	Option  func(*options)

run.go

@@ -32,6 +32,10 @@ import (
 //   - log.Option
 //   - run.Option
 //   - func(context.Context) error
+//
+// By default, above args are statics which could not change according to the configuration.
+// If the args need to by dynamic, it should be wrapped in func() []any,
+// which returns args according to the configuration.
 func Run(args ...any) error {
 	// Setup configuration first so others can use it.
 	var configOpts []config.Option