client: functional opts for constructor

v2/client/client.go

@@ -31,12 +31,37 @@ const DefaultUserAgent = "voucher-client/2"
 
 // NewClient creates a new Client set to connect to the passed
 // hostname.
-func NewClient(voucherURL string) (*Client, error) {
-	return newClient(voucherURL, &http.Client{})
+func NewClient(voucherURL string, opts ...Option) (*Client, error) {
+	return newClient(voucherURL, &http.Client{}, opts...)
+}
+
+type Option func(*Client)
+
+// WithHTTPClient sets the http.Client to use for the client.
+func WithHTTPClient(httpClient *http.Client) Option {
+	return func(c *Client) {
+		c.httpClient = httpClient
+	}
+}
+
+// WithUserAgent sets the User-Agent header for the client.
+func WithUserAgent(userAgent string) Option {
+	return func(c *Client) {
+		c.userAgent = userAgent
+	}
+}
+
+// WithBasicAuth sets the username and password to use for the client.
+func WithBasicAuth(username, password string) Option {
+	return func(c *Client) {
+		c.username = username
+		c.password = password
+	}
 }
 
 // NewAuthClient creates a new auth Client set to connect to the passed
 // hostname using tokens.
+// Deprecated: use the WithHTTPClient option instead
 func NewAuthClient(voucherURL string) (*Client, error) {
 	authClient, err := idtoken.NewClient(context.Background(), voucherURL)
 	if err != nil {
@@ -45,23 +70,13 @@ func NewAuthClient(voucherURL string) (*Client, error) {
 	return newClient(voucherURL, authClient)
 }
 
-// NewCustomClient creates a new Client set to connect to passed
-// hostname using a passed http client
-func NewCustomClient(voucherURL string, client *http.Client) (*Client, error) {
-	return newClient(voucherURL, client)
-}
-
 // SetBasicAuth adds the username and password to the Client struct
+// Deprecated: use the WithBasicAuth option instead
 func (c *Client) SetBasicAuth(username, password string) {
 	c.username = username
 	c.password = password
 }
 
-// SetUserAgent customizes the user agent used by the client
-func (c *Client) SetUserAgent(userAgent string) {
-	c.userAgent = userAgent
-}
-
 // CopyURL returns a copy of this client's URL
 func (c *Client) CopyURL() *url.URL {
 	urlCopy := (*c.url)
@@ -117,7 +132,7 @@ func (c *Client) doVoucherRequest(ctx context.Context, url string, image referen
 	return &voucherResp, nil
 }
 
-func newClient(voucherURL string, httpClient *http.Client) (*Client, error) {
+func newClient(voucherURL string, httpClient *http.Client, options ...Option) (*Client, error) {
 	if voucherURL == "" {
 		return nil, errNoHost
 	}
@@ -135,5 +150,8 @@ func newClient(voucherURL string, httpClient *http.Client) (*Client, error) {
 		httpClient: httpClient,
 		userAgent:  DefaultUserAgent,
 	}
+	for _, opt := range options {
+		opt(client)
+	}
 	return client, nil
 }

v2/client/client_test.go

@@ -70,8 +70,7 @@ func TestVoucher_CustomUserAgent(t *testing.T) {
 	srv := httptest.NewServer(v)
 	defer srv.Close()
 
-	c, err := client.NewClient(srv.URL)
-	c.SetUserAgent(customUserAgent)
+	c, err := client.NewClient(srv.URL, client.WithUserAgent(customUserAgent))
 	require.NoError(t, err)
 	res, err := c.Check(context.Background(), "diy", canonical(t, image))
 	require.NoError(t, err)

v2/cmd/voucher_client/config.go

@@ -8,6 +8,7 @@ import (
 
 	voucher "github.com/grafeas/voucher/v2"
 	"github.com/grafeas/voucher/v2/client"
+	"google.golang.org/api/idtoken"
 )
 
 type config struct {
@@ -26,30 +27,35 @@ func getCheck() string {
 }
 
 func getVoucherClient() (voucher.Interface, error) {
-	var newClient *client.Client
-	var err error
+	options := []client.Option{
+		client.WithUserAgent(fmt.Sprintf("voucher-client/%s", version)),
+	}
 	switch strings.ToLower(defaultConfig.Auth) {
-	case "idtoken":
-		newClient, err = client.NewAuthClient(defaultConfig.Server)
-		if err != nil {
-			return nil, err
-		}
 	case "basic":
-		newClient, err = client.NewClient(defaultConfig.Server)
+		options = append(options, client.WithBasicAuth(defaultConfig.Username, defaultConfig.Password))
+
+	case "idtoken":
+		idClient, err := idtoken.NewClient(context.Background(), defaultConfig.Server)
 		if err != nil {
 			return nil, err
 		}
-		newClient.SetBasicAuth(defaultConfig.Username, defaultConfig.Password)
+		options = append(options, client.WithHTTPClient(idClient))
+
 	case "default-access-token":
-		newClient, err = NewAuthClientWithToken(context.Background(), defaultConfig.Server)
+		tokenClient, err := getDefaultTokenSourceClient(context.Background())
 		if err != nil {
 			return nil, err
 		}
+		options = append(options, client.WithHTTPClient(tokenClient))
+
 	default:
 		return nil, fmt.Errorf("invalid auth value: %q", defaultConfig.Auth)
 	}
 
-	newClient.SetUserAgent(fmt.Sprintf("voucher-client/%s", version))
+	newClient, err := client.NewClient(defaultConfig.Server, options...)
+	if err != nil {
+		return nil, err
+	}
 	return newClient, nil
 }
 

v2/cmd/voucher_client/defaultclient.go

@@ -5,7 +5,6 @@ import (
 	"fmt"
 	"net/http"
 
-	"github.com/grafeas/voucher/v2/client"
 	"golang.org/x/oauth2"
 	"golang.org/x/oauth2/google"
 	"google.golang.org/api/option"
@@ -39,33 +38,16 @@ func (s *idTokenSource) Token() (*oauth2.Token, error) {
 	}, nil
 }
 
-// NewAuthClientWithToken creates an auth client using the token created from ADC
-func NewAuthClientWithToken(ctx context.Context, voucherURL string) (*client.Client, error) {
-	ts, err := getDefaultTokenSource(ctx)
-	if err != nil {
-		return nil, err
-	}
-
-	c, err := newHTTPClient(ctx, ts)
-	if err != nil {
-		return nil, err
-	}
-	return client.NewCustomClient(voucherURL, c)
-}
-
-func getDefaultTokenSource(ctx context.Context) (oauth2.TokenSource, error) {
+func getDefaultTokenSourceClient(ctx context.Context) (*http.Client, error) {
 	src, err := google.DefaultTokenSource(ctx)
 	if err != nil {
 		return nil, fmt.Errorf("error creating token source: %w", err)
 	}
 	ts := oauth2.ReuseTokenSource(nil, &idTokenSource{TokenSource: src})
-	return ts, nil
-}
 
-func newHTTPClient(ctx context.Context, ts oauth2.TokenSource) (*http.Client, error) {
-	t, err := htransport.NewTransport(ctx, http.DefaultTransport, option.WithTokenSource(ts))
+	transport, err := htransport.NewTransport(ctx, http.DefaultTransport, option.WithTokenSource(ts))
 	if err != nil {
 		return nil, fmt.Errorf("error creating client: %w", err)
 	}
-	return &http.Client{Transport: t}, nil
+	return &http.Client{Transport: transport}, nil
 }