init

backend/database.go

@@ -0,0 +1,105 @@
+package main
+
+import (
+	"database/sql"
+	"fmt"
+	"os"
+
+	_ "github.com/go-sql-driver/mysql"
+)
+
+// DB is the shared database connection pool used by the application.
+var DB *sql.DB
+
+// InitDB opens a connection to the MariaDB/MySQL database using credentials
+// from the environment, creates the database if it does not exist, and ensures
+// the required tables are present.
+func InitDB() (*sql.DB, error) {
+	password := os.Getenv("DB_PASSWORD")
+	if password == "" {
+		password = "secret"
+	}
+
+	// Build the DSN. The host "db" matches the service name in docker-compose.yml.
+	dsn := fmt.Sprintf("oworganizer:%s@tcp(db:3306)/?parseTime=true", password)
+
+	db, err := sql.Open("mysql", dsn)
+	if err != nil {
+		return nil, fmt.Errorf("failed to open database: %w", err)
+	}
+
+	if err := db.Ping(); err != nil {
+		return nil, fmt.Errorf("failed to ping database: %w", err)
+	}
+
+	// Ensure the application database exists.
+	if _, err := db.Exec("CREATE DATABASE IF NOT EXISTS oworganizer CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci"); err != nil {
+		return nil, fmt.Errorf("failed to create database: %w", err)
+	}
+
+	// Switch to the application database.
+	if _, err := db.Exec("USE oworganizer"); err != nil {
+		return nil, fmt.Errorf("failed to select database: %w", err)
+	}
+
+	// Ensure required tables exist.
+	if err := createTables(db); err != nil {
+		return nil, fmt.Errorf("failed to create tables: %w", err)
+	}
+
+	return db, nil
+}
+
+// tableExists reports whether a table with the given name exists in the current
+// database.
+func tableExists(db *sql.DB, name string) (bool, error) {
+	var exists bool
+	query := `
+		SELECT EXISTS (
+			SELECT 1
+			FROM INFORMATION_SCHEMA.TABLES
+			WHERE TABLE_SCHEMA = DATABASE()
+			  AND TABLE_NAME = ?
+		)
+	`
+	err := db.QueryRow(query, name).Scan(&exists)
+	if err != nil {
+		return false, err
+	}
+	return exists, nil
+}
+
+// createTables creates the application's tables if they do not already exist.
+func createTables(db *sql.DB) error {
+	tables := map[string]string{
+		"users": `
+			CREATE TABLE IF NOT EXISTS users (
+				userId VARCHAR(255) PRIMARY KEY,
+				rootObjectId VARCHAR(255) NOT NULL
+			) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci
+		`,
+		"objects": `
+			CREATE TABLE IF NOT EXISTS objects (
+				objectId VARCHAR(255) PRIMARY KEY,
+				userId VARCHAR(255) NOT NULL,
+				objectData TEXT NOT NULL
+			) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci
+		`,
+	}
+
+	for name, ddl := range tables {
+		exists, err := tableExists(db, name)
+		if err != nil {
+			return fmt.Errorf("failed to check %s table: %w", name, err)
+		}
+		if exists {
+			continue
+		}
+
+		if _, err := db.Exec(ddl); err != nil {
+			return fmt.Errorf("failed to create %s table: %w", name, err)
+		}
+	}
+
+	return nil
+}