chore: Move dialer options out of cmd/main.go and into internal/proxy…

….go (#1247)

Move dialer options out of cmd/main.go and into internal/proxy.go. This consolidates all code relating to cloud.google.com/go/cloudsqlconn into the internal/proxy package.

cmd/root.go

@@ -29,15 +29,12 @@ import (
 	"syscall"
 	"time"
 
-	"cloud.google.com/go/cloudsqlconn"
 	"contrib.go.opencensus.io/exporter/prometheus"
 	"contrib.go.opencensus.io/exporter/stackdriver"
 	"github.com/GoogleCloudPlatform/cloudsql-proxy/v2/cloudsql"
-	"github.com/GoogleCloudPlatform/cloudsql-proxy/v2/internal/gcloud"
 	"github.com/GoogleCloudPlatform/cloudsql-proxy/v2/internal/proxy"
 	"github.com/spf13/cobra"
 	"go.opencensus.io/trace"
-	"golang.org/x/oauth2"
 )
 
 var (
@@ -162,6 +159,8 @@ func parseConfig(cmd *cobra.Command, conf *proxy.Config, args []string) error {
 		return newBadCommandError("missing instance_connection_name (e.g., project:region:instance)")
 	}
 
+	conf.UserAgent = userAgent
+
 	userHasSet := func(f string) bool {
 		return cmd.PersistentFlags().Lookup(f).Changed
 	}
@@ -185,34 +184,6 @@ 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")
 	}
-	conf.DialerOpts = []cloudsqlconn.Option{
-		cloudsqlconn.WithUserAgent(userAgent),
-	}
-	switch {
-	case conf.Token != "":
-		cmd.Printf("Authorizing with the -token flag\n")
-		conf.DialerOpts = append(conf.DialerOpts, cloudsqlconn.WithTokenSource(
-			oauth2.StaticTokenSource(&oauth2.Token{AccessToken: conf.Token}),
-		))
-	case conf.CredentialsFile != "":
-		cmd.Printf("Authorizing with the credentials file at %q\n", conf.CredentialsFile)
-		conf.DialerOpts = append(conf.DialerOpts, cloudsqlconn.WithCredentialsFile(
-			conf.CredentialsFile,
-		))
-	case conf.GcloudAuth:
-		cmd.Println("Authorizing with gcloud user credentials")
-		ts, err := gcloud.TokenSource()
-		if err != nil {
-			return err
-		}
-		conf.DialerOpts = append(conf.DialerOpts, cloudsqlconn.WithTokenSource(ts))
-	default:
-		cmd.Println("Authorizing with Application Default Credentials")
-	}
-
-	if conf.IAMAuthN {
-		conf.DialerOpts = append(conf.DialerOpts, cloudsqlconn.WithIAMAuthN())
-	}
 
 	if userHasSet("http-port") && !userHasSet("prometheus-namespace") {
 		return newBadCommandError("cannot specify --http-port without --prometheus-namespace")
@@ -406,18 +377,7 @@ 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 = cloudsqlconn.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

@@ -26,7 +26,6 @@ import (
 	"cloud.google.com/go/cloudsqlconn"
 	"github.com/GoogleCloudPlatform/cloudsql-proxy/v2/internal/proxy"
 	"github.com/google/go-cmp/cmp"
-	"github.com/google/go-cmp/cmp/cmpopts"
 	"github.com/spf13/cobra"
 )
 
@@ -36,6 +35,9 @@ func TestNewCommandArguments(t *testing.T) {
 	trueValue := true
 
 	withDefaults := func(c *proxy.Config) *proxy.Config {
+		if c.UserAgent == "" {
+			c.UserAgent = userAgent
+		}
 		if c.Addr == "" {
 			c.Addr = "127.0.0.1"
 		}
@@ -218,8 +220,7 @@ 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

@@ -26,7 +26,9 @@ import (
 
 	"cloud.google.com/go/cloudsqlconn"
 	"github.com/GoogleCloudPlatform/cloudsql-proxy/v2/cloudsql"
+	"github.com/GoogleCloudPlatform/cloudsql-proxy/v2/internal/gcloud"
 	"github.com/spf13/cobra"
+	"golang.org/x/oauth2"
 )
 
 // InstanceConnConfig holds the configuration for an individual instance
@@ -49,6 +51,9 @@ type InstanceConnConfig struct {
 
 // Config contains all the configuration provided by the caller.
 type Config struct {
+	// UserAgent is the user agent to use when connecting to the cloudsql instance
+	UserAgent string
+
 	// Token is the Bearer token used for authorization.
 	Token string
 
@@ -81,10 +86,37 @@ type Config struct {
 	// Dialer specifies the dialer to use when connecting to Cloud SQL
 	// instances.
 	Dialer cloudsql.Dialer
+}
+
+// DialerOptions builds appropriate list of options from the Config
+// values for use by cloudsqlconn.NewClient()
+func (c *Config) DialerOptions() ([]cloudsqlconn.Option, error) {
+	opts := []cloudsqlconn.Option{
+		cloudsqlconn.WithUserAgent(c.UserAgent),
+	}
+	switch {
+	case c.Token != "":
+		opts = append(opts, cloudsqlconn.WithTokenSource(
+			oauth2.StaticTokenSource(&oauth2.Token{AccessToken: c.Token}),
+		))
+	case c.CredentialsFile != "":
+		opts = append(opts, cloudsqlconn.WithCredentialsFile(
+			c.CredentialsFile,
+		))
+	case c.GcloudAuth:
+		ts, err := gcloud.TokenSource()
+		if err != nil {
+			return nil, err
+		}
+		opts = append(opts, cloudsqlconn.WithTokenSource(ts))
+	default:
+	}
+
+	if c.IAMAuthN {
+		opts = append(opts, cloudsqlconn.WithIAMAuthN())
+	}
 
-	// DialerOpts specifies the opts to use when creating a new dialer. This
-	// value is ignored when a Dialer has been set.
-	DialerOpts []cloudsqlconn.Option
+	return opts, nil
 }
 
 type portConfig struct {
@@ -140,7 +172,22 @@ type Client struct {
 }
 
 // NewClient completes the initial setup required to get the proxy to a "steady" state.
-func NewClient(ctx context.Context, d cloudsql.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 = cloudsqlconn.NewDialer(ctx, dialerOpts...)
+		if err != nil {
+			return nil, fmt.Errorf("error initializing dialer: %v", err)
+		}
+	}
+
 	var mnts []*socketMount
 	for _, inst := range conf.Instances {
 		go func(name string) {

internal/proxy/proxy_test.go

@@ -211,7 +211,8 @@ 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)
 			}
@@ -254,14 +255,16 @@ func TestClientInitializationWorksRepeatedly(t *testing.T) {
 		Instances: []proxy.InstanceConnConfig{
 			{Name: "proj:region:pg"},
 		},
+		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)
 	}