chore: move dialer options to proxy.Config (#61)

This is a port of GoogleCloudPlatform/cloud-sql-proxy#1247

cmd/root.go

@@ -29,15 +29,12 @@ import (
 	"syscall"
 	"time"
 
-	"cloud.google.com/go/alloydbconn"
 	"contrib.go.opencensus.io/exporter/prometheus"
 	"contrib.go.opencensus.io/exporter/stackdriver"
 	"github.com/GoogleCloudPlatform/alloydb-auth-proxy/alloydb"
-	"github.com/GoogleCloudPlatform/alloydb-auth-proxy/internal/gcloud"
 	"github.com/GoogleCloudPlatform/alloydb-auth-proxy/internal/proxy"
 	"github.com/spf13/cobra"
 	"go.opencensus.io/trace"
-	"golang.org/x/oauth2"
 )
 
 var (
@@ -171,6 +168,9 @@ func parseConfig(cmd *cobra.Command, conf *proxy.Config, args []string) error {
 	if len(args) == 0 {
 		return newBadCommandError("missing instance uri (e.g., /projects/$PROJECTS/locations/$LOCTION/clusters/$CLUSTER/instances/$INSTANCES)")
 	}
+
+	conf.UserAgent = userAgent
+
 	userHasSet := func(f string) bool {
 		return cmd.PersistentFlags().Lookup(f).Changed
 	}
@@ -195,31 +195,6 @@ func parseConfig(cmd *cobra.Command, conf *proxy.Config, args []string) error {
 	if conf.CredentialsFile != "" && conf.GcloudAuth {
 		return newBadCommandError("cannot specify --credentials-file and --gcloud-auth flags at the same time")
 	}
-	opts := []alloydbconn.Option{
-		alloydbconn.WithUserAgent(userAgent),
-	}
-	switch {
-	case conf.Token != "":
-		cmd.Printf("Authorizing with the -token flag\n")
-		opts = append(opts, alloydbconn.WithTokenSource(
-			oauth2.StaticTokenSource(&oauth2.Token{AccessToken: conf.Token}),
-		))
-	case conf.CredentialsFile != "":
-		cmd.Printf("Authorizing with the credentials file at %q\n", conf.CredentialsFile)
-		opts = append(opts, alloydbconn.WithCredentialsFile(
-			conf.CredentialsFile,
-		))
-	case conf.GcloudAuth:
-		cmd.Println("Authorizing with gcloud user credentials")
-		ts, err := gcloud.TokenSource()
-		if err != nil {
-			return err
-		}
-		opts = append(opts, alloydbconn.WithTokenSource(ts))
-	default:
-		cmd.Println("Authorizing with Application Default Credentials")
-	}
-	conf.DialerOpts = opts
 
 	if userHasSet("http-port") && !userHasSet("prometheus-namespace") {
 		return newBadCommandError("cannot specify --http-port without --prometheus-namespace")
@@ -394,18 +369,7 @@ func runSignalWrapper(cmd *Command) error {
 	startCh := make(chan *proxy.Client)
 	go func() {
 		defer close(startCh)
-		// Check if the caller has configured a dialer.
-		// Otherwise, initialize a new one.
-		d := cmd.conf.Dialer
-		if d == nil {
-			var err error
-			d, err = alloydbconn.NewDialer(ctx, cmd.conf.DialerOpts...)
-			if err != nil {
-				shutdownCh <- fmt.Errorf("error initializing dialer: %v", err)
-				return
-			}
-		}
-		p, err := proxy.NewClient(ctx, d, cmd.Command, cmd.conf)
+		p, err := proxy.NewClient(ctx, cmd.Command, cmd.conf)
 		if err != nil {
 			shutdownCh <- fmt.Errorf("unable to start: %v", err)
 			return

cmd/root_test.go

@@ -27,12 +27,14 @@ import (
 	"cloud.google.com/go/alloydbconn"
 	"github.com/GoogleCloudPlatform/alloydb-auth-proxy/internal/proxy"
 	"github.com/google/go-cmp/cmp"
-	"github.com/google/go-cmp/cmp/cmpopts"
 	"github.com/spf13/cobra"
 )
 
 func TestNewCommandArguments(t *testing.T) {
 	withDefaults := func(c *proxy.Config) *proxy.Config {
+		if c.UserAgent == "" {
+			c.UserAgent = userAgent
+		}
 		if c.Addr == "" {
 			c.Addr = "127.0.0.1"
 		}
@@ -180,8 +182,7 @@ func TestNewCommandArguments(t *testing.T) {
 				t.Fatalf("want error = nil, got = %v", err)
 			}
 
-			opts := cmpopts.IgnoreFields(proxy.Config{}, "DialerOpts")
-			if got := c.conf; !cmp.Equal(tc.want, got, opts) {
+			if got := c.conf; !cmp.Equal(tc.want, got) {
 				t.Fatalf("want = %#v\ngot = %#v\ndiff = %v", tc.want, got, cmp.Diff(tc.want, got))
 			}
 		})

internal/proxy/proxy.go

@@ -28,7 +28,9 @@ import (
 
 	"cloud.google.com/go/alloydbconn"
 	"github.com/GoogleCloudPlatform/alloydb-auth-proxy/alloydb"
+	"github.com/GoogleCloudPlatform/alloydb-auth-proxy/internal/gcloud"
 	"github.com/spf13/cobra"
+	"golang.org/x/oauth2"
 )
 
 // InstanceConnConfig holds the configuration for an individual instance
@@ -48,6 +50,10 @@ type InstanceConnConfig struct {
 
 // Config contains all the configuration provided by the caller.
 type Config struct {
+	// UserAgent is the user agent to use when sending requests to the Admin
+	// API.
+	UserAgent string
+
 	// Token is the Bearer token used for authorization.
 	Token string
 
@@ -76,10 +82,33 @@ type Config struct {
 	// Dialer specifies the dialer to use when connecting to AlloyDB
 	// instances.
 	Dialer alloydb.Dialer
+}
+
+// DialerOptions builds appropriate list of options from the Config
+// values for use by alloydbconn.NewClient()
+func (c *Config) DialerOptions() ([]alloydbconn.Option, error) {
+	opts := []alloydbconn.Option{
+		alloydbconn.WithUserAgent(c.UserAgent),
+	}
+	switch {
+	case c.Token != "":
+		opts = append(opts, alloydbconn.WithTokenSource(
+			oauth2.StaticTokenSource(&oauth2.Token{AccessToken: c.Token}),
+		))
+	case c.CredentialsFile != "":
+		opts = append(opts, alloydbconn.WithCredentialsFile(
+			c.CredentialsFile,
+		))
+	case c.GcloudAuth:
+		ts, err := gcloud.TokenSource()
+		if err != nil {
+			return nil, err
+		}
+		opts = append(opts, alloydbconn.WithTokenSource(ts))
+	default:
+	}
 
-	// DialerOpts specifies the opts to use when creating a new dialer. This
-	// value is ignored when a Dialer has been set.
-	DialerOpts []alloydbconn.Option
+	return opts, nil
 }
 
 type portConfig struct {
@@ -131,7 +160,22 @@ type Client struct {
 }
 
 // NewClient completes the initial setup required to get the proxy to a "steady" state.
-func NewClient(ctx context.Context, d alloydb.Dialer, cmd *cobra.Command, conf *Config) (*Client, error) {
+func NewClient(ctx context.Context, cmd *cobra.Command, conf *Config) (*Client, error) {
+	// Check if the caller has configured a dialer.
+	// Otherwise, initialize a new one.
+	d := conf.Dialer
+	if d == nil {
+		var err error
+		dialerOpts, err := conf.DialerOptions()
+		if err != nil {
+			return nil, fmt.Errorf("error initializing dialer: %v", err)
+		}
+		d, err = alloydbconn.NewDialer(ctx, dialerOpts...)
+		if err != nil {
+			return nil, fmt.Errorf("error initializing dialer: %v", err)
+		}
+	}
+
 	pc := newPortConfig(conf.Port)
 	var mnts []*socketMount
 	for _, inst := range conf.Instances {

internal/proxy/proxy_test.go

@@ -185,7 +185,8 @@ func TestClientInitialization(t *testing.T) {
 
 	for _, tc := range tcs {
 		t.Run(tc.desc, func(t *testing.T) {
-			c, err := proxy.NewClient(ctx, fakeDialer{}, &cobra.Command{}, tc.in)
+			tc.in.Dialer = fakeDialer{}
+			c, err := proxy.NewClient(ctx, &cobra.Command{}, tc.in)
 			if err != nil {
 				t.Fatalf("want error = nil, got = %v", err)
 			}
@@ -228,14 +229,15 @@ func TestClientInitializationWorksRepeatedly(t *testing.T) {
 		Instances: []proxy.InstanceConnConfig{
 			{Name: "/projects/proj/locations/region/clusters/clust/instances/inst1"},
 		},
+		Dialer: fakeDialer{},
 	}
-	c, err := proxy.NewClient(ctx, fakeDialer{}, &cobra.Command{}, in)
+	c, err := proxy.NewClient(ctx, &cobra.Command{}, in)
 	if err != nil {
 		t.Fatalf("want error = nil, got = %v", err)
 	}
 	c.Close()
 
-	c, err = proxy.NewClient(ctx, fakeDialer{}, &cobra.Command{}, in)
+	c, err = proxy.NewClient(ctx, &cobra.Command{}, in)
 	if err != nil {
 		t.Fatalf("want error = nil, got = %v", err)
 	}