build multi tenant

migration/migrator.go

@@ -0,0 +1,155 @@
+package migration
+
+import (
+	"database/sql"
+	"fmt"
+	"io/ioutil"
+	"path/filepath"
+	"sort"
+	"strings"
+
+	"github.com/jmoiron/sqlx"
+)
+
+// Migration represents a database migration
+type Migration struct {
+	Version string
+	Name    string
+	SQL     string
+}
+
+// Migrator handles database migrations
+type Migrator struct {
+	db            *sqlx.DB
+	migrationsDir string
+}
+
+// NewMigrator creates a new migrator instance
+func NewMigrator(db *sqlx.DB, migrationsDir string) *Migrator {
+	return &Migrator{
+		db:            db,
+		migrationsDir: migrationsDir,
+	}
+}
+
+// Run executes all pending migrations
+func (m *Migrator) Run() error {
+	// Create migrations table if it doesn't exist
+	if err := m.createMigrationsTable(); err != nil {
+		return fmt.Errorf("failed to create migrations table: %w", err)
+	}
+
+	// Get all migration files
+	migrations, err := m.loadMigrations()
+	if err != nil {
+		return fmt.Errorf("failed to load migrations: %w", err)
+	}
+
+	// Get applied migrations
+	appliedMigrations, err := m.getAppliedMigrations()
+	if err != nil {
+		return fmt.Errorf("failed to get applied migrations: %w", err)
+	}
+
+	// Apply pending migrations
+	for _, migration := range migrations {
+		if !contains(appliedMigrations, migration.Version) {
+			if err := m.applyMigration(migration); err != nil {
+				return fmt.Errorf("failed to apply migration %s: %w", migration.Version, err)
+			}
+			fmt.Printf("Applied migration: %s - %s\n", migration.Version, migration.Name)
+		}
+	}
+
+	return nil
+}
+
+// createMigrationsTable creates the migrations tracking table
+func (m *Migrator) createMigrationsTable() error {
+	query := `
+		CREATE TABLE IF NOT EXISTS schema_migrations (
+			version VARCHAR(255) PRIMARY KEY,
+			applied_at TIMESTAMP NOT NULL DEFAULT NOW()
+		)
+	`
+	_, err := m.db.Exec(query)
+	return err
+}
+
+// loadMigrations loads all migration files from the migrations directory
+func (m *Migrator) loadMigrations() ([]Migration, error) {
+	files, err := filepath.Glob(filepath.Join(m.migrationsDir, "*.sql"))
+	if err != nil {
+		return nil, err
+	}
+
+	var migrations []Migration
+	for _, file := range files {
+		content, err := ioutil.ReadFile(file)
+		if err != nil {
+			return nil, err
+		}
+
+		filename := filepath.Base(file)
+		parts := strings.SplitN(filename, "_", 2)
+		if len(parts) != 2 {
+			continue // Skip files that don't match the pattern
+		}
+
+		version := parts[0]
+		name := strings.TrimSuffix(parts[1], ".sql")
+
+		migrations = append(migrations, Migration{
+			Version: version,
+			Name:    name,
+			SQL:     string(content),
+		})
+	}
+
+	// Sort migrations by version
+	sort.Slice(migrations, func(i, j int) bool {
+		return migrations[i].Version < migrations[j].Version
+	})
+
+	return migrations, nil
+}
+
+// getAppliedMigrations returns a list of applied migration versions
+func (m *Migrator) getAppliedMigrations() ([]string, error) {
+	var versions []string
+	err := m.db.Select(&versions, "SELECT version FROM schema_migrations ORDER BY version")
+	return versions, err
+}
+
+// applyMigration applies a single migration
+func (m *Migrator) applyMigration(migration Migration) error {
+	tx, err := m.db.Beginx()
+	if err != nil {
+		return err
+	}
+	defer tx.Rollback()
+
+	// Execute the migration SQL
+	_, err = tx.Exec(migration.SQL)
+	if err != nil {
+		return err
+	}
+
+	// Record the migration as applied
+	_, err = tx.Exec("INSERT INTO schema_migrations (version) VALUES ($1)", migration.Version)
+	if err != nil {
+		return err
+	}
+
+	return tx.Commit()
+}
+
+// contains checks if a slice contains a string
+func contains(slice []string, item string) bool {
+	for _, s := range slice {
+		if s == item {
+			return true
+		}
+	}
+	return false
+}