initialize database if table doesn't exist

countersql/database.go

@@ -86,3 +86,31 @@ func (conf Configuration) Connect() (*Connection, error) {
 
 	return conn, nil
 }
+
+// InitializeDatabase will check if tables exist in the database, and if not then create them.
+func (conn Connection) InitializeDatabase() error {
+	rows, err := conn.DB.Query(`SHOW TABLES`)
+	if err != nil {
+		return fmt.Errorf("SHOW TABLES query failed: %v", err)
+	}
+	defer rows.Close()
+
+	if rows.Next() { // Table already exists, leave with no error
+		return nil
+	}
+
+	// Table does not exist, create it
+	_, err = conn.DB.Exec(`CREATE TABLE visit (
+		id int(11) NOT NULL AUTO_INCREMENT,
+		ip_address varchar(15) NOT NULL,
+		visits int(11) NOT NULL,
+		last_visited datetime NOT NULL,
+		PRIMARY KEY (id)
+	  ) ENGINE=InnoDB DEFAULT CHARSET=latin1;`)
+
+	if err != nil {
+		return fmt.Errorf("failed to create table: %v", err)
+	}
+
+	return nil
+}

main.go

@@ -57,6 +57,13 @@ func init() {
 		log.Fatalf("failed to connect to database: %v", err)
 	}
 
+	// Check if database needs to be initialized (create tables)
+	// does nothing if tables exist
+	err = dbConn.InitializeDatabase()
+	if err != nil {
+		log.Fatalf("failed to initialize database: %v", err)
+	}
+
 	uniqueVisits, err = dbConn.GetUniqueVisits()
 	if err != nil {
 		log.Fatalf("failed to get number of unique visits from database: %v", err)