/*
 Licensed to the Apache Software Foundation (ASF) under one
 or more contributor license agreements.  See the NOTICE file
 distributed with this work for additional information
 regarding copyright ownership.  The ASF licenses this file
 to you under the Apache License, Version 2.0 (the
 "License"); you may not use this file except in compliance
 with the License.  You may obtain a copy of the License at

     http://www.apache.org/licenses/LICENSE-2.0

 Unless required by applicable law or agreed to in writing, software
 distributed under the License is distributed on an "AS IS" BASIS,
 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.
*/

package interfaces

// a common interface for app management service
// an app management service monitors the lifecycle of applications,
// it is responsible for reporting application status to the scheduler,
// that helps the scheduler to manage the application lifecycle natively.
type AppManager interface {
	// the name of this application service
	// this info is exposed to the scheduler so we know what kind of apps
	// the scheduler is able to supervise.
	Name() string

	// if the service needs to init any objects, this is the place
	// the initialization of the service must not start any of go routines,
	// this will be called before starting the service.
	ServiceInit() error

	// if the service has some internal stuff to run, this is the place to run them.
	// some implementation may not need to implement this.
	Start() error

	// if there is some go routines running in start, properly stop them while
	// the stop() function is called.
	Stop()
}