tools: serpapi api key option (#773)

feat: serpapi api key options

tools/serpapi/options.go

@@ -0,0 +1,15 @@
+package serpapi
+
+type options struct {
+	apiKey string
+}
+
+type Option func(*options)
+
+// WithAPIKey passes the Serpapi API token to the client. If not set, the token
+// is read from the SERPAPI_API_KEY environment variable.
+func WithAPIKey(apiKey string) Option {
+	return func(opts *options) {
+		opts.apiKey = apiKey
+	}
+}

tools/serpapi/serpapi.go

@@ -21,14 +21,21 @@ type Tool struct {
 var _ tools.Tool = Tool{}
 
 // New creates a new serpapi tool to search on internet.
-func New() (*Tool, error) {
-	apiKey := os.Getenv("SERPAPI_API_KEY")
-	if apiKey == "" {
+func New(opts ...Option) (*Tool, error) {
+	options := &options{
+		apiKey: os.Getenv("SERPAPI_API_KEY"),
+	}
+
+	for _, opt := range opts {
+		opt(options)
+	}
+
+	if options.apiKey == "" {
 		return nil, ErrMissingToken
 	}
 
 	return &Tool{
-		client: internal.New(apiKey),
+		client: internal.New(options.apiKey),
 	}, nil
 }