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| 1 | +//go:build !nomysql |
| 2 | + |
| 3 | +package sql_exporter |
| 4 | + |
| 5 | +import ( |
| 6 | + "crypto/tls" |
| 7 | + "crypto/x509" |
| 8 | + "errors" |
| 9 | + "fmt" |
| 10 | + "log/slog" |
| 11 | + "net/url" |
| 12 | + "os" |
| 13 | + "sync" |
| 14 | + |
| 15 | + "github.com/go-sql-driver/mysql" |
| 16 | +) |
| 17 | + |
| 18 | +const ( |
| 19 | + mysqlTLSParamCACert = "tls-ca" |
| 20 | + mysqlTLSParamClientCert = "tls-cert" |
| 21 | + mysqlTLSParamClientKey = "tls-key" |
| 22 | +) |
| 23 | + |
| 24 | +// mysqlTLSParams is a list of TLS parameters that can be used in MySQL DSNs. It is used to identify and strip TLS |
| 25 | +// parameters from the DSN after registering the TLS configuration, as these parameters are not recognized by the MySQL |
| 26 | +// driver and would cause connection failure if left in the DSN. |
| 27 | +var ( |
| 28 | + mysqlTLSParams = []string{mysqlTLSParamCACert, mysqlTLSParamClientCert, mysqlTLSParamClientKey} |
| 29 | + |
| 30 | + onceMap sync.Map |
| 31 | +) |
| 32 | + |
| 33 | +// handleMySQLTLSConfig wraps the registration of a MySQL TLS configuration in a thread-safe manner. It uses a |
| 34 | +// sync.Once to ensure that the TLS configuration for a given config name is registered only once, even if multiple |
| 35 | +// goroutines attempt to register it concurrently. |
| 36 | +func handleMySQLTLSConfig(configName string, params url.Values) error { |
| 37 | + onceConn, _ := onceMap.LoadOrStore(configName, &sync.Once{}) |
| 38 | + once := onceConn.(*sync.Once) |
| 39 | + var err error |
| 40 | + once.Do(func() { |
| 41 | + err = registerMySQLTLSConfig(configName, params) |
| 42 | + if err != nil { |
| 43 | + slog.Error("Failed to register MySQL TLS config", "error", err) |
| 44 | + } |
| 45 | + }) |
| 46 | + return err |
| 47 | +} |
| 48 | + |
| 49 | +// registerMySQLTLSConfig registers a custom TLS configuration for MySQL with the given config name and parameters. |
| 50 | +func registerMySQLTLSConfig(configName string, params url.Values) error { |
| 51 | + caCert := params.Get(mysqlTLSParamCACert) |
| 52 | + clientCert := params.Get(mysqlTLSParamClientCert) |
| 53 | + clientKey := params.Get(mysqlTLSParamClientKey) |
| 54 | + |
| 55 | + slog.Debug("MySQL TLS config", "configName", configName, mysqlTLSParamCACert, caCert, |
| 56 | + mysqlTLSParamClientCert, clientCert, mysqlTLSParamClientKey, clientKey) |
| 57 | + |
| 58 | + var rootCertPool *x509.CertPool |
| 59 | + if caCert != "" { |
| 60 | + rootCertPool = x509.NewCertPool() |
| 61 | + pem, err := os.ReadFile(caCert) |
| 62 | + if err != nil { |
| 63 | + return fmt.Errorf("failed to read CA certificate: %w", err) |
| 64 | + } |
| 65 | + if ok := rootCertPool.AppendCertsFromPEM(pem); !ok { |
| 66 | + return errors.New("failed to append PEM") |
| 67 | + } |
| 68 | + } |
| 69 | + |
| 70 | + var certs []tls.Certificate |
| 71 | + if clientCert != "" || clientKey != "" { |
| 72 | + if clientCert == "" || clientKey == "" { |
| 73 | + return errors.New("both tls-cert and tls-key must be provided for client authentication") |
| 74 | + } |
| 75 | + cert, err := tls.LoadX509KeyPair(clientCert, clientKey) |
| 76 | + if err != nil { |
| 77 | + return fmt.Errorf("failed to load client certificate and key: %w", err) |
| 78 | + } |
| 79 | + certs = append(certs, cert) |
| 80 | + } |
| 81 | + |
| 82 | + tlsConfig := &tls.Config{ |
| 83 | + RootCAs: rootCertPool, |
| 84 | + Certificates: certs, |
| 85 | + MinVersion: tls.VersionTLS12, |
| 86 | + } |
| 87 | + |
| 88 | + return mysql.RegisterTLSConfig(configName, tlsConfig) |
| 89 | +} |
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