fix(tls): Pass certificate and private key files to listener method (#531)

Fixes #530

README.md

@@ -1278,14 +1278,14 @@ Confused? Read [Securing Gatus with OIDC using Auth0](https://twin.sh/articles/5
 
 ### TLS Encryption
 Gatus supports basic encryption with TLS. To enable this, certificate files in PEM format have to be provided.
-The example below shows an example configuration which makes gatus respond on port 4443 to HTTPS requests.
 
+The example below shows an example configuration which makes gatus respond on port 4443 to HTTPS requests:
 ```yaml
 web:
   port: 4443
   tls:
-    certificate-file: "server.crt"
+    certificate-file: "certificate.crt"
-    private-key-file: "server.key"
+    private-key-file: "private.key"
 ```
 
 ### Metrics

config/web/web.go

@@ -34,8 +34,6 @@ type TLSConfig struct {
 
 	// PrivateKeyFile is the private key file for TLS in PEM format.
 	PrivateKeyFile string `yaml:"private-key-file,omitempty"`
-
-	tlsConfig *tls.Config
 }
 
 // GetDefaultConfig returns a Config struct with the default values
@@ -57,33 +55,29 @@ func (web *Config) ValidateAndSetDefaults() error {
 	}
 	// Try to load the TLS certificates
 	if web.TLS != nil {
-		if err := web.TLS.loadConfig(); err != nil {
+		if err := web.TLS.isValid(); err != nil {
 			return fmt.Errorf("invalid tls config: %w", err)
 		}
 	}
 	return nil
 }
 
+func (web *Config) HasTLS() bool {
+	return web.TLS != nil && len(web.TLS.CertificateFile) > 0 && len(web.TLS.PrivateKeyFile) > 0
+}
+
 // SocketAddress returns the combination of the Address and the Port
 func (web *Config) SocketAddress() string {
 	return fmt.Sprintf("%s:%d", web.Address, web.Port)
 }
 
-func (t *TLSConfig) loadConfig() error {
+func (t *TLSConfig) isValid() error {
 	if len(t.CertificateFile) > 0 && len(t.PrivateKeyFile) > 0 {
-		certificate, err := tls.LoadX509KeyPair(t.CertificateFile, t.PrivateKeyFile)
+		_, err := tls.LoadX509KeyPair(t.CertificateFile, t.PrivateKeyFile)
 		if err != nil {
 			return err
 		}
-		t.tlsConfig = &tls.Config{Certificates: []tls.Certificate{certificate}}
 		return nil
 	}
 	return errors.New("certificate-file and private-key-file must be specified")
 }
-
-func (web *Config) TLSConfig() *tls.Config {
-	if web.TLS != nil {
-		return web.TLS.tlsConfig
-	}
-	return nil
-}

config/web/web_test.go

@@ -37,6 +37,27 @@ func TestConfig_ValidateAndSetDefaults(t *testing.T) {
 			cfg:         &Config{Port: 100000000},
 			expectedErr: true,
 		},
+		{
+			name:            "with-good-tls-config",
+			cfg:             &Config{Port: 443, TLS: &TLSConfig{CertificateFile: "../../testdata/cert.pem", PrivateKeyFile: "../../testdata/cert.key"}},
+			expectedAddress: "0.0.0.0",
+			expectedPort:    443,
+			expectedErr:     false,
+		},
+		{
+			name:            "with-bad-tls-config",
+			cfg:             &Config{Port: 443, TLS: &TLSConfig{CertificateFile: "../../testdata/badcert.pem", PrivateKeyFile: "../../testdata/cert.key"}},
+			expectedAddress: "0.0.0.0",
+			expectedPort:    443,
+			expectedErr:     true,
+		},
+		{
+			name:            "with-partial-tls-config",
+			cfg:             &Config{Port: 443, TLS: &TLSConfig{CertificateFile: "", PrivateKeyFile: "../../testdata/cert.key"}},
+			expectedAddress: "0.0.0.0",
+			expectedPort:    443,
+			expectedErr:     true,
+		},
 	}
 	for _, scenario := range scenarios {
 		t.Run(scenario.name, func(t *testing.T) {
@@ -67,7 +88,7 @@ func TestConfig_SocketAddress(t *testing.T) {
 	}
 }
 
-func TestConfig_TLSConfig(t *testing.T) {
+func TestConfig_isValid(t *testing.T) {
 	scenarios := []struct {
 		name        string
 		cfg         *Config
@@ -79,27 +100,37 @@ func TestConfig_TLSConfig(t *testing.T) {
 			expectedErr: false,
 		},
 		{
-			name:        "missing-crt-file",
+			name:        "missing-certificate-file",
 			cfg:         &Config{TLS: &TLSConfig{CertificateFile: "doesnotexist", PrivateKeyFile: "../../testdata/cert.key"}},
 			expectedErr: true,
 		},
 		{
-			name:        "bad-crt-file",
+			name:        "bad-certificate-file",
 			cfg:         &Config{TLS: &TLSConfig{CertificateFile: "../../testdata/badcert.pem", PrivateKeyFile: "../../testdata/cert.key"}},
 			expectedErr: true,
 		},
+		{
+			name:        "no-certificate-file",
+			cfg:         &Config{TLS: &TLSConfig{CertificateFile: "", PrivateKeyFile: "../../testdata/cert.key"}},
+			expectedErr: true,
+		},
 		{
 			name:        "missing-private-key-file",
 			cfg:         &Config{TLS: &TLSConfig{CertificateFile: "../../testdata/cert.pem", PrivateKeyFile: "doesnotexist"}},
 			expectedErr: true,
 		},
+		{
+			name:        "no-private-key-file",
+			cfg:         &Config{TLS: &TLSConfig{CertificateFile: "../../testdata/cert.pem", PrivateKeyFile: ""}},
+			expectedErr: true,
+		},
 		{
 			name:        "bad-private-key-file",
 			cfg:         &Config{TLS: &TLSConfig{CertificateFile: "../../testdata/cert.pem", PrivateKeyFile: "../../testdata/badcert.key"}},
 			expectedErr: true,
 		},
 		{
-			name:        "bad-cert-and-private-key-file",
+			name:        "bad-certificate-and-private-key-file",
 			cfg:         &Config{TLS: &TLSConfig{CertificateFile: "../../testdata/badcert.pem", PrivateKeyFile: "../../testdata/badcert.key"}},
 			expectedErr: true,
 		},
@@ -112,8 +143,8 @@ func TestConfig_TLSConfig(t *testing.T) {
 				return
 			}
 			if !scenario.expectedErr {
-				if scenario.cfg.TLS.tlsConfig == nil {
+				if scenario.cfg.TLS.isValid() != nil {
-					t.Error("TLS configuration was not correctly loaded although no error was returned")
+					t.Error("cfg.TLS.isValid() returned an error even though no error was expected")
 				}
 			}
 		})

controller/controller.go

@@ -22,16 +22,22 @@ func Handle(cfg *config.Config) {
 	server.ReadTimeout = 15 * time.Second
 	server.WriteTimeout = 15 * time.Second
 	server.IdleTimeout = 15 * time.Second
-	server.TLSConfig = cfg.Web.TLSConfig()
 	if os.Getenv("ROUTER_TEST") == "true" {
 		return
 	}
 	log.Println("[controller][Handle] Listening on " + cfg.Web.SocketAddress())
-	if server.TLSConfig != nil {
+	if cfg.Web.HasTLS() {
-		log.Println("[controller][Handle]", app.ListenTLS(cfg.Web.SocketAddress(), "", ""))
+		err := app.ListenTLS(cfg.Web.SocketAddress(), cfg.Web.TLS.CertificateFile, cfg.Web.TLS.PrivateKeyFile)
-	} else {
+		if err != nil {
-		log.Println("[controller][Handle]", app.Listen(cfg.Web.SocketAddress()))
+			log.Fatal("[controller][Handle]", err)
 		}
+	} else {
+		err := app.Listen(cfg.Web.SocketAddress())
+		if err != nil {
+			log.Fatal("[controller][Handle]", err)
+		}
+	}
+	log.Println("[controller][Handle] Server has shut down successfully")
 }
 
 // Shutdown stops the server