tlsutil: un-ptr and add godoc to autoTLs struct

the autoTLS field on Configurator is only set once. By making it a value receiver it
should be allocated as a single block of memory along with Configurator.

Also add godoc to document what it is used for.

tlsutil/config.go

@@ -150,6 +150,8 @@ func SpecificDC(dc string, tlsWrap DCWrapper) Wrapper {
 	}
 }
 
+// autoTLS stores configuration that is received from the auto-encrypt or
+// auto-config features.
 type autoTLS struct {
 	manualCAPems         []string
 	connectCAPems        []string
@@ -157,7 +159,7 @@ type autoTLS struct {
 	verifyServerHostname bool
 }
 
-func (a *autoTLS) caPems() []string {
+func (a autoTLS) caPems() []string {
 	return append(a.manualCAPems, a.connectCAPems...)
 }
 
@@ -172,7 +174,7 @@ type Configurator struct {
 	// lock synchronizes access to all fields on this struct except for logger and version.
 	lock                 sync.RWMutex
 	base                 *Config
-	autoTLS              *autoTLS
+	autoTLS              autoTLS
 	manual               *manual
 	peerDatacenterUseTLS map[string]bool
 	caPool               *x509.CertPool
@@ -197,7 +199,6 @@ func NewConfigurator(config Config, logger hclog.Logger) (*Configurator, error)
 	c := &Configurator{
 		logger:               logger.Named(logging.TLSUtil),
 		manual:               &manual{},
-		autoTLS:              &autoTLS{},
 		peerDatacenterUseTLS: map[string]bool{},
 	}
 	err := c.Update(config)
@@ -274,7 +275,7 @@ func (c *Configurator) UpdateAutoTLSCA(connectCAPems []string) error {
 	return nil
 }
 
-// UpdateAutoTLSCert
+// UpdateAutoTLSCert receives the updated Auto-Encrypt certificate.
 func (c *Configurator) UpdateAutoTLSCert(pub, priv string) error {
 	cert, err := tls.X509KeyPair([]byte(pub), []byte(priv))
 	if err != nil {
@@ -290,8 +291,8 @@ func (c *Configurator) UpdateAutoTLSCert(pub, priv string) error {
 	return nil
 }
 
-// UpdateAutoTLS sets everything under autoEncrypt. This is being called on the
+// UpdateAutoTLS receives updates from Auto-Config, only expected to be called on
-// client when it received its cert from AutoEncrypt/AutoConfig endpoints.
+// client agents.
 func (c *Configurator) UpdateAutoTLS(manualCAPems, connectCAPems []string, pub, priv string, verifyServerHostname bool) error {
 	cert, err := tls.X509KeyPair([]byte(pub), []byte(priv))
 	if err != nil {

tlsutil/config_test.go

@@ -506,7 +506,7 @@ func TestConfigurator_ErrorPropagation(t *testing.T) {
 		variants = append(variants, variant{Config{TLSMinVersion: v}, false, false})
 	}
 
-	c := Configurator{autoTLS: &autoTLS{}, manual: &manual{}}
+	c := Configurator{manual: &manual{}}
 	for i, v := range variants {
 		info := fmt.Sprintf("case %d, config: %+v", i, v.config)
 		_, err1 := NewConfigurator(v.config, nil)
@@ -716,7 +716,7 @@ func TestConfigurator_CommonTLSConfigTLSMinVersion(t *testing.T) {
 }
 
 func TestConfigurator_CommonTLSConfigVerifyIncoming(t *testing.T) {
-	c := Configurator{base: &Config{}, autoTLS: &autoTLS{}}
+	c := Configurator{base: &Config{}}
 	type variant struct {
 		verify   bool
 		expected tls.ClientAuthType
@@ -731,7 +731,7 @@ func TestConfigurator_CommonTLSConfigVerifyIncoming(t *testing.T) {
 }
 
 func TestConfigurator_OutgoingRPCTLSDisabled(t *testing.T) {
-	c := Configurator{base: &Config{}, autoTLS: &autoTLS{}}
+	c := Configurator{base: &Config{}}
 	type variant struct {
 		verify         bool
 		autoEncryptTLS bool
@@ -909,7 +909,7 @@ func TestConfigurator_IncomingALPNRPCConfig(t *testing.T) {
 }
 
 func TestConfigurator_IncomingHTTPSConfig(t *testing.T) {
-	c := Configurator{base: &Config{}, autoTLS: &autoTLS{}}
+	c := Configurator{base: &Config{}}
 	require.Equal(t, []string{"h2", "http/1.1"}, c.IncomingHTTPSConfig().NextProtos)
 }
 
@@ -917,7 +917,7 @@ func TestConfigurator_OutgoingTLSConfigForChecks(t *testing.T) {
 	c := Configurator{base: &Config{
 		TLSMinVersion:           "tls12",
 		EnableAgentTLSForChecks: false,
-	}, autoTLS: &autoTLS{}}
+	}}
 	tlsConf := c.OutgoingTLSConfigForCheck(true, "")
 	require.Equal(t, true, tlsConf.InsecureSkipVerify)
 	require.Equal(t, uint16(0), tlsConf.MinVersion)
@@ -936,7 +936,7 @@ func TestConfigurator_OutgoingTLSConfigForChecks(t *testing.T) {
 }
 
 func TestConfigurator_OutgoingRPCConfig(t *testing.T) {
-	c := &Configurator{base: &Config{}, autoTLS: &autoTLS{}}
+	c := &Configurator{base: &Config{}}
 	require.Nil(t, c.OutgoingRPCConfig())
 
 	c, err := NewConfigurator(Config{
@@ -954,7 +954,7 @@ func TestConfigurator_OutgoingRPCConfig(t *testing.T) {
 }
 
 func TestConfigurator_OutgoingALPNRPCConfig(t *testing.T) {
-	c := &Configurator{base: &Config{}, autoTLS: &autoTLS{}}
+	c := &Configurator{base: &Config{}}
 	require.Nil(t, c.OutgoingALPNRPCConfig())
 
 	c, err := NewConfigurator(Config{
@@ -974,7 +974,7 @@ func TestConfigurator_OutgoingALPNRPCConfig(t *testing.T) {
 }
 
 func TestConfigurator_OutgoingRPCWrapper(t *testing.T) {
-	c := &Configurator{base: &Config{}, autoTLS: &autoTLS{}}
+	c := &Configurator{base: &Config{}}
 	wrapper := c.OutgoingRPCWrapper()
 	require.NotNil(t, wrapper)
 	conn := &net.TCPConn{}
@@ -996,7 +996,7 @@ func TestConfigurator_OutgoingRPCWrapper(t *testing.T) {
 }
 
 func TestConfigurator_OutgoingALPNRPCWrapper(t *testing.T) {
-	c := &Configurator{base: &Config{}, autoTLS: &autoTLS{}}
+	c := &Configurator{base: &Config{}}
 	wrapper := c.OutgoingRPCWrapper()
 	require.NotNil(t, wrapper)
 	conn := &net.TCPConn{}
@@ -1071,7 +1071,7 @@ func TestConfigurator_ServerNameOrNodeName(t *testing.T) {
 }
 
 func TestConfigurator_VerifyOutgoing(t *testing.T) {
-	c := Configurator{base: &Config{}, autoTLS: &autoTLS{}}
+	c := Configurator{base: &Config{}}
 	type variant struct {
 		verify         bool
 		autoEncryptTLS bool
@@ -1104,7 +1104,7 @@ func TestConfigurator_Domain(t *testing.T) {
 }
 
 func TestConfigurator_VerifyServerHostname(t *testing.T) {
-	c := Configurator{base: &Config{}, autoTLS: &autoTLS{}}
+	c := Configurator{base: &Config{}}
 	require.False(t, c.VerifyServerHostname())
 
 	c.base.VerifyServerHostname = true
@@ -1121,7 +1121,7 @@ func TestConfigurator_VerifyServerHostname(t *testing.T) {
 }
 
 func TestConfigurator_AutoEncrytCertExpired(t *testing.T) {
-	c := Configurator{base: &Config{}, autoTLS: &autoTLS{}}
+	c := Configurator{base: &Config{}}
 	require.True(t, c.AutoEncryptCertExpired())
 
 	cert, err := loadKeyPair("../test/key/something_expired.cer", "../test/key/something_expired.key")