init

internal/db/db.go

@@ -0,0 +1,50 @@
+package db
+
+import (
+	"context"
+	"database/sql"
+	"fmt"
+	"os"
+
+	_ "github.com/go-sql-driver/mysql"
+)
+
+func Open(ctx context.Context, url string) (*sql.DB, error) {
+	d, err := sql.Open("mysql", url)
+	if err != nil {
+		return nil, err
+	}
+	if err := d.PingContext(ctx); err != nil {
+		return nil, err
+	}
+	return d, nil
+}
+
+func Migrate(ctx context.Context, d *sql.DB) error {
+	d.ExecContext(ctx, `SELECT GET_LOCK('trading_tool_migrate', 30)`)
+	defer d.ExecContext(ctx, `SELECT RELEASE_LOCK('trading_tool_migrate')`)
+	if _, err := d.ExecContext(ctx, `CREATE TABLE IF NOT EXISTS schema_migrations(version VARCHAR(255) PRIMARY KEY, applied_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP)`); err != nil {
+		return err
+	}
+	files := []string{"migrations/001_init.sql", "migrations/002_admin.sql"}
+	for _, f := range files {
+		var exists bool
+		if err := d.QueryRowContext(ctx, `SELECT EXISTS(SELECT 1 FROM schema_migrations WHERE version=?)`, f).Scan(&exists); err != nil {
+			return err
+		}
+		if exists {
+			continue
+		}
+		b, err := os.ReadFile(f)
+		if err != nil {
+			return err
+		}
+		if _, err := d.ExecContext(ctx, string(b)); err != nil {
+			return fmt.Errorf("%s: %w", f, err)
+		}
+		if _, err := d.ExecContext(ctx, `INSERT INTO schema_migrations(version) VALUES(?)`, f); err != nil {
+			return err
+		}
+	}
+	return nil
+}