feat: PostgreSQL driver support

internal/infrastructure/config/databaseSettings.go

@@ -13,9 +13,14 @@ const (
 	DatabaseDriverSQLite = "sqlite"
 	DatabaseDriverMySQL  = "mysql"
 
+	DatabaseDriverPostgres      = "postgres"
+	databaseDriverPostgresAlias = "postgresql"
+
 	DefaultDatabaseDriver          = DatabaseDriverSQLite
 	DefaultDatabasePort            = "3306"
+	DefaultPostgresPort            = "5432"
 	DefaultDatabaseTLS             = "false"
+	DefaultDatabaseSSLMode         = "disable"
 	DefaultMaxOpenConns            = "10"
 	DefaultMaxIdleConns            = "5"
 	DefaultConnMaxLifetimeSeconds  = "300"
@@ -26,6 +31,7 @@ const (
 	envDatabasePassword            = "DB_PASSWORD"
 	envDatabaseName                = "DB_NAME"
 	envDatabaseTLS                 = "DB_TLS"
+	envDatabaseSSLMode             = "DB_SSLMODE"
 	envDatabaseMaxOpenConns        = "DB_MAX_OPEN_CONNS"
 	envDatabaseMaxIdleConns        = "DB_MAX_IDLE_CONNS"
 	envDatabaseConnMaxLifetimeSecs = "DB_CONN_MAX_LIFETIME_SECONDS"
@@ -35,6 +41,8 @@ var mysqlRequiredEnvVars = []string{envDatabaseHost, envDatabaseUser, envDatabas
 
 var DatabaseTLSModes = []string{"false", "true", "skip-verify", "preferred"}
 
+var DatabaseSSLModes = []string{"disable", "require", "verify-ca", "verify-full"}
+
 type DatabaseSettings struct {
 	Driver          string
 	Host            string
@@ -43,13 +51,22 @@ type DatabaseSettings struct {
 	Password        string
 	Name            string
 	TLS             string
+	SSLMode         string
 	MaxOpenConns    int
 	MaxIdleConns    int
 	ConnMaxLifetime time.Duration
 }
 
+func NormalizeDatabaseDriver(driver string) string {
+	if driver == databaseDriverPostgresAlias {
+		return DatabaseDriverPostgres
+	}
+	return driver
+}
+
 func DatabaseRequiredEnvVars(driver string) []string {
-	if driver == DatabaseDriverMySQL {
+	switch NormalizeDatabaseDriver(driver) {
+	case DatabaseDriverMySQL, DatabaseDriverPostgres:
 		return slices.Clone(mysqlRequiredEnvVars)
 	}
 	return nil
@@ -65,18 +82,27 @@ func MissingEnvVarError(names []string, lookup func(string) (string, bool)) erro
 }
 
 func databaseDriverFromEnv() string {
-	return envOrDefault(EnvDatabaseDriver, DefaultDatabaseDriver)
+	return NormalizeDatabaseDriver(envOrDefault(EnvDatabaseDriver, DefaultDatabaseDriver))
 }
 
 func databaseSettingsFromEnv() (DatabaseSettings, error) {
 	driver := databaseDriverFromEnv()
-	if driver != DatabaseDriverMySQL {
+	if driver != DatabaseDriverMySQL && driver != DatabaseDriverPostgres {
 		return DatabaseSettings{Driver: driver}, nil
 	}
 
-	tls := envOrDefault(envDatabaseTLS, DefaultDatabaseTLS)
-	if !slices.Contains(DatabaseTLSModes, tls) {
-		return DatabaseSettings{}, fmt.Errorf("%s must be one of %s, got %q", envDatabaseTLS, strings.Join(DatabaseTLSModes, ", "), tls)
+	defaultPort, tls, sslMode := DefaultDatabasePort, "", ""
+	if driver == DatabaseDriverPostgres {
+		defaultPort = DefaultPostgresPort
+		sslMode = envOrDefault(envDatabaseSSLMode, DefaultDatabaseSSLMode)
+		if !slices.Contains(DatabaseSSLModes, sslMode) {
+			return DatabaseSettings{}, fmt.Errorf("%s must be one of %s, got %q", envDatabaseSSLMode, strings.Join(DatabaseSSLModes, ", "), sslMode)
+		}
+	} else {
+		tls = envOrDefault(envDatabaseTLS, DefaultDatabaseTLS)
+		if !slices.Contains(DatabaseTLSModes, tls) {
+			return DatabaseSettings{}, fmt.Errorf("%s must be one of %s, got %q", envDatabaseTLS, strings.Join(DatabaseTLSModes, ", "), tls)
+		}
 	}
 	maxOpen, err := nonNegativeIntEnv(envDatabaseMaxOpenConns, DefaultMaxOpenConns)
 	if err != nil {
@@ -94,11 +120,12 @@ func databaseSettingsFromEnv() (DatabaseSettings, error) {
 	return DatabaseSettings{
 		Driver:          driver,
 		Host:            os.Getenv(envDatabaseHost),
-		Port:            envOrDefault(envDatabasePort, DefaultDatabasePort),
+		Port:            envOrDefault(envDatabasePort, defaultPort),
 		User:            os.Getenv(envDatabaseUser),
 		Password:        os.Getenv(envDatabasePassword),
 		Name:            os.Getenv(envDatabaseName),
 		TLS:             tls,
+		SSLMode:         sslMode,
 		MaxOpenConns:    maxOpen,
 		MaxIdleConns:    maxIdle,
 		ConnMaxLifetime: time.Duration(lifetimeSeconds) * time.Second,