The district court properly applied the Colorado River abstention doctrine to dismiss this case which plaintiff filed to obtain declaratory and injunctive relief against a California city and Coastal Commission suit in state court to enforce local zoning and other requirements on plaintiff. In deciding on Colorado River abstention, the court employs an eight-factor balancing test. Only the consideration that federal law provides the rule of decision weighs against dismissal of the federal action, but not substantially so given that the state court has concurrent jurisdiction to adjudicate federal preemption issues. Neither an inadequate state court forum nor insufficiently parallel proceedings, which preclude the use of a Colorado River dismissal, are present here. The forum shopping and piecemeal litigation considerations strongly favor dismissal, and the order in which the forums obtained jurisdiction also supports that outcome.