fix: update CI Go version to match go.mod, add DSN parser package

Author: Meru143

.github/workflows/ci.yml

@@ -15,7 +15,7 @@ jobs:
       - name: Set up Go
         uses: actions/setup-go@v5
         with:
-          go-version: '1.21'
+          go-version-file: 'go.mod'
 
       - name: Download dependencies
         run: go mod download

internal/db/dsn/parser.go

@@ -0,0 +1,295 @@
+// Package dsn provides DSN parsing utilities for multiple database backends.
+// It converts various URL formats into the native DSN strings expected by
+// each database driver.
+package dsn
+
+import (
+	"fmt"
+	"net/url"
+	"strings"
+)
+
+// Config holds parsed connection parameters
+type Config struct {
+	Driver   string // "postgres", "mysql", "sqlserver"
+	Host     string
+	Port     string
+	User     string
+	Password string
+	Database string
+	Params   map[string]string
+}
+
+// Parse converts a connection string into a Config struct.
+// Supported formats:
+//   - postgres://user:pass@host:port/dbname?sslmode=disable
+//   - mysql://user:pass@tcp(host:port)/dbname?parseTime=true
+//   - sqlserver://user:pass@host:port?database=dbname
+func Parse(connStr string) (*Config, error) {
+	lower := strings.ToLower(connStr)
+
+	switch {
+	case strings.HasPrefix(lower, "postgres://"), strings.HasPrefix(lower, "postgresql://"):
+		return parsePostgres(connStr)
+	case strings.HasPrefix(lower, "mysql://"), strings.HasPrefix(lower, "mysql+tcp://"):
+		return parseMySQL(connStr)
+	case strings.HasPrefix(lower, "sqlserver://"):
+		return parseSQLServer(connStr)
+	default:
+		return nil, fmt.Errorf("unsupported connection string format: %s", connStr)
+	}
+}
+
+// ToNativeDSN converts a Config back to the native DSN expected by the driver.
+func (c *Config) ToNativeDSN() string {
+	switch c.Driver {
+	case "postgres":
+		return c.toPostgresDSN()
+	case "mysql":
+		return c.toMySQLDSN()
+	case "sqlserver":
+		return c.toSQLServerDSN()
+	default:
+		return ""
+	}
+}
+
+func parsePostgres(connStr string) (*Config, error) {
+	u, err := url.Parse(connStr)
+	if err != nil {
+		return nil, fmt.Errorf("invalid postgres URL: %w", err)
+	}
+
+	cfg := &Config{
+		Driver: "postgres",
+		Host:   u.Hostname(),
+		Port:   u.Port(),
+		Params: make(map[string]string),
+	}
+
+	if cfg.Port == "" {
+		cfg.Port = "5432"
+	}
+
+	if u.User != nil {
+		cfg.User = u.User.Username()
+		cfg.Password, _ = u.User.Password()
+	}
+
+	cfg.Database = strings.TrimPrefix(u.Path, "/")
+
+	for k, v := range u.Query() {
+		cfg.Params[k] = v[0]
+	}
+
+	return cfg, nil
+}
+
+func parseMySQL(connStr string) (*Config, error) {
+	// MySQL URLs: mysql://user:pass@tcp(host:port)/dbname?params
+	// or mysql://user:pass@host:port/dbname?params
+
+	// Strip the mysql:// prefix
+	raw := connStr
+	if strings.HasPrefix(strings.ToLower(raw), "mysql+tcp://") {
+		raw = "mysql://" + raw[12:]
+	}
+
+	// Check for tcp() format: mysql://user:pass@tcp(host:port)/dbname
+	if idx := strings.Index(raw, "tcp("); idx != -1 {
+		return parseMySQLTCP(raw)
+	}
+
+	// Standard URL format: mysql://user:pass@host:port/dbname
+	u, err := url.Parse(raw)
+	if err != nil {
+		return nil, fmt.Errorf("invalid mysql URL: %w", err)
+	}
+
+	cfg := &Config{
+		Driver: "mysql",
+		Host:   u.Hostname(),
+		Port:   u.Port(),
+		Params: make(map[string]string),
+	}
+
+	if cfg.Port == "" {
+		cfg.Port = "3306"
+	}
+
+	if u.User != nil {
+		cfg.User = u.User.Username()
+		cfg.Password, _ = u.User.Password()
+	}
+
+	cfg.Database = strings.TrimPrefix(u.Path, "/")
+
+	for k, v := range u.Query() {
+		cfg.Params[k] = v[0]
+	}
+
+	return cfg, nil
+}
+
+func parseMySQLTCP(raw string) (*Config, error) {
+	// Format: mysql://user:pass@tcp(host:port)/dbname?params
+	cfg := &Config{
+		Driver: "mysql",
+		Params: make(map[string]string),
+	}
+
+	// Remove mysql://
+	raw = raw[8:]
+
+	// Split on @tcp(
+	atIdx := strings.Index(raw, "@tcp(")
+	if atIdx == -1 {
+		return nil, fmt.Errorf("invalid mysql tcp format")
+	}
+
+	userPart := raw[:atIdx]
+	rest := raw[atIdx+5:] // after "@tcp("
+
+	// Parse user:pass
+	if colonIdx := strings.Index(userPart, ":"); colonIdx != -1 {
+		cfg.User = userPart[:colonIdx]
+		cfg.Password = userPart[colonIdx+1:]
+	} else {
+		cfg.User = userPart
+	}
+
+	// Parse host:port)/dbname?params
+	closeIdx := strings.Index(rest, ")")
+	if closeIdx == -1 {
+		return nil, fmt.Errorf("invalid mysql tcp format: missing closing paren")
+	}
+
+	hostPort := rest[:closeIdx]
+	afterParen := rest[closeIdx+1:]
+
+	if colonIdx := strings.LastIndex(hostPort, ":"); colonIdx != -1 {
+		cfg.Host = hostPort[:colonIdx]
+		cfg.Port = hostPort[colonIdx+1:]
+	} else {
+		cfg.Host = hostPort
+		cfg.Port = "3306"
+	}
+
+	// Parse /dbname?params
+	if strings.HasPrefix(afterParen, "/") {
+		afterParen = afterParen[1:]
+	}
+
+	if qIdx := strings.Index(afterParen, "?"); qIdx != -1 {
+		cfg.Database = afterParen[:qIdx]
+		queryStr := afterParen[qIdx+1:]
+
+		for _, pair := range strings.Split(queryStr, "&") {
+			if eqIdx := strings.Index(pair, "="); eqIdx != -1 {
+				cfg.Params[pair[:eqIdx]] = pair[eqIdx+1:]
+			}
+		}
+	} else {
+		cfg.Database = afterParen
+	}
+
+	return cfg, nil
+}
+
+func parseSQLServer(connStr string) (*Config, error) {
+	u, err := url.Parse(connStr)
+	if err != nil {
+		return nil, fmt.Errorf("invalid sqlserver URL: %w", err)
+	}
+
+	cfg := &Config{
+		Driver: "sqlserver",
+		Host:   u.Hostname(),
+		Port:   u.Port(),
+		Params: make(map[string]string),
+	}
+
+	if cfg.Port == "" {
+		cfg.Port = "1433"
+	}
+
+	if u.User != nil {
+		cfg.User = u.User.Username()
+		cfg.Password, _ = u.User.Password()
+	}
+
+	// SQL Server uses ?database=dbname instead of /dbname
+	for k, v := range u.Query() {
+		if strings.ToLower(k) == "database" {
+			cfg.Database = v[0]
+		} else {
+			cfg.Params[k] = v[0]
+		}
+	}
+
+	// Also check the path for /dbname if no database param
+	if cfg.Database == "" {
+		cfg.Database = strings.TrimPrefix(u.Path, "/")
+	}
+
+	return cfg, nil
+}
+
+func (c *Config) toPostgresDSN() string {
+	u := &url.URL{
+		Scheme: "postgres",
+		Host:   fmt.Sprintf("%s:%s", c.Host, c.Port),
+		Path:   c.Database,
+	}
+	if c.User != "" {
+		if c.Password != "" {
+			u.User = url.UserPassword(c.User, c.Password)
+		} else {
+			u.User = url.User(c.User)
+		}
+	}
+	q := url.Values{}
+	for k, v := range c.Params {
+		q.Set(k, v)
+	}
+	u.RawQuery = q.Encode()
+	return u.String()
+}
+
+func (c *Config) toMySQLDSN() string {
+	// go-sql-driver format: user:pass@tcp(host:port)/dbname?params
+	dsn := fmt.Sprintf("%s:%s@tcp(%s:%s)/%s",
+		c.User, c.Password, c.Host, c.Port, c.Database)
+
+	if len(c.Params) > 0 {
+		params := make([]string, 0, len(c.Params))
+		for k, v := range c.Params {
+			params = append(params, fmt.Sprintf("%s=%s", k, v))
+		}
+		dsn += "?" + strings.Join(params, "&")
+	}
+	return dsn
+}
+
+func (c *Config) toSQLServerDSN() string {
+	u := &url.URL{
+		Scheme: "sqlserver",
+		Host:   fmt.Sprintf("%s:%s", c.Host, c.Port),
+	}
+	if c.User != "" {
+		if c.Password != "" {
+			u.User = url.UserPassword(c.User, c.Password)
+		} else {
+			u.User = url.User(c.User)
+		}
+	}
+	q := url.Values{}
+	if c.Database != "" {
+		q.Set("database", c.Database)
+	}
+	for k, v := range c.Params {
+		q.Set(k, v)
+	}
+	u.RawQuery = q.Encode()
+	return u.String()
+}