chore: move all cloudsql.Instance references behind methods (#678)

This is the first step to extracting an interface for cloudsql.Instance.

Also, prefer full words (cfg vs config) for types, field names, and
compound variable names.

dialer.go

@@ -81,9 +81,9 @@ type Dialer struct {
 
 	sqladmin *sqladmin.Service
 
-	// defaultDialCfg holds the constructor level DialOptions, so that it can
-	// be copied and mutated by the Dial function.
-	defaultDialCfg dialCfg
+	// defaultDialConfig holds the constructor level DialOptions, so that it
+	// can be copied and mutated by the Dial function.
+	defaultDialConfig dialConfig
 
 	// dialerID uniquely identifies a Dialer. Used for monitoring purposes,
 	// *only* when a client has configured OpenCensus exporters.
@@ -157,10 +157,10 @@ func NewDialer(ctx context.Context, opts ...Option) (*Dialer, error) {
 		return nil, fmt.Errorf("failed to create sqladmin client: %v", err)
 	}
 
-	dc := dialCfg{
+	dc := dialConfig{
 		ipType:       cloudsql.PublicIP,
 		tcpKeepAlive: defaultTCPKeepAlive,
-		refreshCfg: cloudsql.RefreshCfg{
+		refreshConfig: cloudsql.RefreshConfig{
 			UseIAMAuthN: cfg.useIAMAuthN,
 		},
 	}
@@ -172,14 +172,14 @@ func NewDialer(ctx context.Context, opts ...Option) (*Dialer, error) {
 		return nil, err
 	}
 	d := &Dialer{
-		instances:      make(map[cloudsql.ConnName]*cloudsql.Instance),
-		key:            cfg.rsaKey,
-		refreshTimeout: cfg.refreshTimeout,
-		sqladmin:       client,
-		defaultDialCfg: dc,
-		dialerID:       uuid.New().String(),
-		iamTokenSource: cfg.iamLoginTokenSource,
-		dialFunc:       cfg.dialFunc,
+		instances:         make(map[cloudsql.ConnName]*cloudsql.Instance),
+		key:               cfg.rsaKey,
+		refreshTimeout:    cfg.refreshTimeout,
+		sqladmin:          client,
+		defaultDialConfig: dc,
+		dialerID:          uuid.New().String(),
+		iamTokenSource:    cfg.iamLoginTokenSource,
+		dialFunc:          cfg.dialFunc,
 	}
 	return d, nil
 }
@@ -202,15 +202,15 @@ func (d *Dialer) Dial(ctx context.Context, instance string, opts ...DialOption)
 		return nil, err
 	}
 
-	cfg := d.defaultDialCfg
+	cfg := d.defaultDialConfig
 	for _, opt := range opts {
 		opt(&cfg)
 	}
 
 	var endInfo trace.EndSpanFunc
 	ctx, endInfo = trace.StartSpan(ctx, "cloud.google.com/go/cloudsqlconn/internal.InstanceInfo")
-	i := d.instance(cn, &cfg.refreshCfg)
-	addr, tlsCfg, err := i.ConnectInfo(ctx, cfg.ipType)
+	i := d.instance(cn, &cfg.refreshConfig)
+	addr, tlsConfig, err := i.ConnectInfo(ctx, cfg.ipType)
 	if err != nil {
 		d.removeInstance(i)
 		endInfo(err)
@@ -241,7 +241,7 @@ func (d *Dialer) Dial(ctx context.Context, instance string, opts ...DialOption)
 		}
 	}
 
-	tlsConn := tls.Client(conn, tlsCfg)
+	tlsConn := tls.Client(conn, tlsConfig)
 	if err := tlsConn.HandshakeContext(ctx); err != nil {
 		// refresh the instance info in case it caused the handshake failure
 		i.ForceRefresh()
@@ -251,13 +251,13 @@ func (d *Dialer) Dial(ctx context.Context, instance string, opts ...DialOption)
 
 	latency := time.Since(startTime).Milliseconds()
 	go func() {
-		n := atomic.AddUint64(&i.OpenConns, 1)
+		n := atomic.AddUint64(i.OpenConns(), 1)
 		trace.RecordOpenConnections(ctx, int64(n), d.dialerID, i.String())
 		trace.RecordDialLatency(ctx, instance, d.dialerID, latency)
 	}()
 
 	return newInstrumentedConn(tlsConn, func() {
-		n := atomic.AddUint64(&i.OpenConns, ^uint64(0))
+		n := atomic.AddUint64(i.OpenConns(), ^uint64(0))
 		trace.RecordOpenConnections(context.Background(), int64(n), d.dialerID, i.String())
 	}), nil
 }
@@ -285,11 +285,11 @@ func (d *Dialer) Warmup(_ context.Context, instance string, opts ...DialOption)
 	if err != nil {
 		return err
 	}
-	cfg := d.defaultDialCfg
+	cfg := d.defaultDialConfig
 	for _, opt := range opts {
 		opt(&cfg)
 	}
-	_ = d.instance(cn, &cfg.refreshCfg)
+	_ = d.instance(cn, &cfg.refreshConfig)
 	return nil
 }
 
@@ -334,26 +334,26 @@ func (d *Dialer) Close() error {
 
 // instance is a helper function for returning the appropriate instance object in a threadsafe way.
 // It will create a new instance object, modify the existing one, or leave it unchanged as needed.
-func (d *Dialer) instance(cn cloudsql.ConnName, r *cloudsql.RefreshCfg) *cloudsql.Instance {
+func (d *Dialer) instance(cn cloudsql.ConnName, r *cloudsql.RefreshConfig) *cloudsql.Instance {
 	// Check instance cache
 	d.lock.RLock()
 	i, ok := d.instances[cn]
 	d.lock.RUnlock()
-	// If the instance hasn't been created yet or if the refreshCfg has changed
-	if !ok || (r != nil && *r != i.RefreshCfg) {
+	// If the instance hasn't been created yet or if the refreshConfig has changed
+	if !ok || (r != nil && *r != i.RefreshConfig()) {
 		d.lock.Lock()
 		// Recheck to ensure instance wasn't created or changed between locks
 		i, ok = d.instances[cn]
 		if !ok {
 			// Create a new instance
 			if r == nil {
-				r = &d.defaultDialCfg.refreshCfg
+				r = &d.defaultDialConfig.refreshConfig
 			}
 			i = cloudsql.NewInstance(cn, d.sqladmin, d.key,
 				d.refreshTimeout, d.iamTokenSource, d.dialerID, *r)
 			d.instances[cn] = i
-		} else if r != nil && *r != i.RefreshCfg {
-			// Update the instance with the new refresh cfg
+		} else if r != nil && *r != i.RefreshConfig() {
+			// Update the instance with the new refresh config
 			i.UpdateRefresh(*r)
 		}
 		d.lock.Unlock()
@@ -366,5 +366,5 @@ func (d *Dialer) removeInstance(i *cloudsql.Instance) {
 	defer d.lock.Unlock()
 	// Stop all background refreshes
 	i.Close()
-	delete(d.instances, i.ConnName)
+	delete(d.instances, i.ConnName())
 }

dialer_test.go

@@ -185,7 +185,7 @@ func TestIAMAuthn(t *testing.T) {
 			if err != nil {
 				t.Fatalf("NewDialer failed with error = %v", err)
 			}
-			if gotIAMAuthN := d.defaultDialCfg.refreshCfg.UseIAMAuthN; gotIAMAuthN != tc.wantIAMAuthN {
+			if gotIAMAuthN := d.defaultDialConfig.refreshConfig.UseIAMAuthN; gotIAMAuthN != tc.wantIAMAuthN {
 				t.Fatalf("want = %v, got = %v", tc.wantIAMAuthN, gotIAMAuthN)
 			}
 		})

internal/cloudsql/instance.go

@@ -120,8 +120,8 @@ func (r *refreshOperation) isValid() bool {
 	}
 }
 
-// RefreshCfg is a collection of attributes that trigger new refresh operations.
-type RefreshCfg struct {
+// RefreshConfig is a collection of attributes that trigger new refresh operations.
+type RefreshConfig struct {
 	UseIAMAuthN bool
 }
 
@@ -130,11 +130,11 @@ type RefreshCfg struct {
 // the required information approximately 4 minutes before the previous
 // certificate expires (every ~56 minutes).
 type Instance struct {
-	// OpenConns is the number of open connections to the instance.
-	OpenConns uint64
+	// openConns is the number of open connections to the instance.
+	openConns uint64
 
-	ConnName
-	key *rsa.PrivateKey
+	connName ConnName
+	key      *rsa.PrivateKey
 
 	// refreshTimeout sets the maximum duration a refresh cycle can run
 	// for.
@@ -143,8 +143,8 @@ type Instance struct {
 	l *rate.Limiter
 	r refresher
 
-	refreshLock sync.RWMutex
-	RefreshCfg  RefreshCfg
+	refreshLock   sync.RWMutex
+	refreshConfig RefreshConfig
 	// cur represents the current refreshOperation that will be used to
 	// create connections. If a valid complete refreshOperation isn't
 	// available it's possible for cur to be equal to next.
@@ -167,11 +167,11 @@ func NewInstance(
 	refreshTimeout time.Duration,
 	ts oauth2.TokenSource,
 	dialerID string,
-	r RefreshCfg,
+	r RefreshConfig,
 ) *Instance {
 	ctx, cancel := context.WithCancel(context.Background())
 	i := &Instance{
-		ConnName: cn,
+		connName: cn,
 		key:      key,
 		l:        rate.NewLimiter(rate.Every(refreshInterval), refreshBurst),
 		r: newRefresher(
@@ -180,7 +180,7 @@ func NewInstance(
 			dialerID,
 		),
 		refreshTimeout: refreshTimeout,
-		RefreshCfg:     r,
+		refreshConfig:  r,
 		ctx:            ctx,
 		cancel:         cancel,
 	}
@@ -193,6 +193,23 @@ func NewInstance(
 	return i
 }
 
+// OpenConns returns a pointer to the number of open connections to
+// faciliate changing the value using atomics.
+func (i *Instance) OpenConns() *uint64 {
+	return &i.openConns
+}
+
+// ConnName returns the instance connection name associated with this Instance.
+func (i *Instance) ConnName() ConnName {
+	return i.connName
+}
+
+// RefreshConfig returns the refresh configuration associated with this
+// instance.
+func (i *Instance) RefreshConfig() RefreshConfig {
+	return i.refreshConfig
+}
+
 // Close closes the instance; it stops the refresh cycle and prevents it from
 // making additional calls to the Cloud SQL Admin API.
 func (i *Instance) Close() {
@@ -245,14 +262,14 @@ func (i *Instance) InstanceEngineVersion(ctx context.Context) (string, error) {
 
 // UpdateRefresh cancels all existing refresh attempts and schedules new
 // attempts with the provided config.
-func (i *Instance) UpdateRefresh(cfg RefreshCfg) {
+func (i *Instance) UpdateRefresh(c RefreshConfig) {
 	i.refreshLock.Lock()
 	defer i.refreshLock.Unlock()
 	// Cancel any pending refreshes
 	i.cur.cancel()
 	i.next.cancel()
 	// update the refresh config as needed
-	i.RefreshCfg = cfg
+	i.refreshConfig = c
 	// reschedule a new refresh immediately
 	i.cur = i.scheduleRefresh(0)
 	i.next = i.cur
@@ -328,12 +345,12 @@ func (i *Instance) scheduleRefresh(d time.Duration) *refreshOperation {
 		if err != nil {
 			r.err = errtype.NewDialError(
 				"context was canceled or expired before refresh completed",
-				i.ConnName.String(),
+				i.connName.String(),
 				nil,
 			)
 		} else {
 			r.result, r.err = i.r.performRefresh(
-				ctx, i.ConnName, i.key, i.RefreshCfg.UseIAMAuthN)
+				ctx, i.connName, i.key, i.refreshConfig.UseIAMAuthN)
 		}
 
 		close(r.ready)
@@ -376,5 +393,5 @@ func (i *Instance) scheduleRefresh(d time.Duration) *refreshOperation {
 
 // String returns the instance's connection name.
 func (i *Instance) String() string {
-	return i.ConnName.String()
+	return i.connName.String()
 }

internal/cloudsql/instance_test.go

@@ -95,7 +95,7 @@ func TestInstanceEngineVersion(t *testing.T) {
 				t.Fatalf("%v", err)
 			}
 		}()
-		i := NewInstance(testInstanceConnName(), client, RSAKey, 30*time.Second, nil, "", RefreshCfg{})
+		i := NewInstance(testInstanceConnName(), client, RSAKey, 30*time.Second, nil, "", RefreshConfig{})
 		if err != nil {
 			t.Fatalf("failed to init instance: %v", err)
 		}
@@ -129,7 +129,7 @@ func TestConnectInfo(t *testing.T) {
 		}
 	}()
 
-	i := NewInstance(testInstanceConnName(), client, RSAKey, 30*time.Second, nil, "", RefreshCfg{})
+	i := NewInstance(testInstanceConnName(), client, RSAKey, 30*time.Second, nil, "", RefreshConfig{})
 
 	gotAddr, gotTLSCfg, err := i.ConnectInfo(ctx, PublicIP)
 	if err != nil {
@@ -194,7 +194,7 @@ func TestConnectInfoAutoIP(t *testing.T) {
 			}
 		}()
 
-		i := NewInstance(testInstanceConnName(), client, RSAKey, 30*time.Second, nil, "", RefreshCfg{})
+		i := NewInstance(testInstanceConnName(), client, RSAKey, 30*time.Second, nil, "", RefreshConfig{})
 		if err != nil {
 			t.Fatalf("failed to create mock instance: %v", err)
 		}
@@ -223,7 +223,7 @@ func TestConnectInfoErrors(t *testing.T) {
 	defer cleanup()
 
 	// Use a timeout that should fail instantly
-	i := NewInstance(testInstanceConnName(), client, RSAKey, 0, nil, "", RefreshCfg{})
+	i := NewInstance(testInstanceConnName(), client, RSAKey, 0, nil, "", RefreshConfig{})
 
 	_, _, err = i.ConnectInfo(ctx, PublicIP)
 	var wantErr *errtype.DialError
@@ -248,7 +248,7 @@ func TestClose(t *testing.T) {
 	defer cleanup()
 
 	// Set up an instance and then close it immediately
-	i := NewInstance(testInstanceConnName(), client, RSAKey, 30, nil, "", RefreshCfg{})
+	i := NewInstance(testInstanceConnName(), client, RSAKey, 30, nil, "", RefreshConfig{})
 	i.Close()
 
 	_, _, err = i.ConnectInfo(ctx, PublicIP)
@@ -311,7 +311,7 @@ func TestContextCancelled(t *testing.T) {
 	defer cleanup()
 
 	// Set up an instance and then close it immediately
-	i := NewInstance(testInstanceConnName(), client, RSAKey, 30, nil, "", RefreshCfg{})
+	i := NewInstance(testInstanceConnName(), client, RSAKey, 30, nil, "", RefreshConfig{})
 	if err != nil {
 		t.Fatalf("failed to initialize Instance: %v", err)
 	}