/ecs-scheduler-service/src/main/java/com/atlassian/buildeng/ecs/SchedulerApplication.java

/*
 * Copyright 2016 - 2017 Atlassian Pty Ltd.
 *
 * Licensed 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 com.atlassian.buildeng.ecs;

import com.atlassian.buildeng.ecs.scheduling.ECSConfiguration;
import com.atlassian.buildeng.ecs.resources.SchedulerResource;
import com.atlassian.buildeng.ecs.resources.HeartBeatResource;
import com.atlassian.buildeng.ecs.resources.LogsResource;
import com.atlassian.buildeng.ecs.scheduling.AWSSchedulerBackend;
import com.atlassian.buildeng.ecs.scheduling.AwsPullModelLoader;
import com.atlassian.buildeng.ecs.scheduling.CyclingECSScheduler;
import com.atlassian.buildeng.ecs.scheduling.DefaultModelUpdater;
import com.atlassian.buildeng.ecs.scheduling.ECSScheduler;
import com.atlassian.buildeng.ecs.scheduling.ModelLoader;
import com.atlassian.buildeng.ecs.scheduling.ModelUpdater;
import com.atlassian.buildeng.ecs.scheduling.SchedulerBackend;
import com.atlassian.buildeng.ecs.scheduling.TaskDefinitionRegistrations;
import com.atlassian.event.api.EventPublisher;
import com.google.inject.AbstractModule;
import com.google.inject.Guice;
import com.google.inject.Injector;
import com.google.inject.name.Names;
import io.dropwizard.Configuration;
import io.dropwizard.setup.Bootstrap;
import io.dropwizard.setup.Environment;
import java.io.Closeable;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import org.apache.commons.lang3.StringUtils;
import org.eclipse.jetty.util.component.AbstractLifeCycle;
import org.eclipse.jetty.util.component.LifeCycle;

/**
 * Created by ojongerius on 09/05/2016.
 */

public class SchedulerApplication extends io.dropwizard.Application<Configuration> {

    public SchedulerApplication() {
    }

    public static void main(String[] args) throws Exception {
        validateEnvironment();
        new SchedulerApplication().run(new String[] {"server"});
    }

    private static void validateEnvironment() {
        if (StringUtils.isBlank(System.getenv(ECSConfigurationImpl.ECS_ASG)) ||
            StringUtils.isBlank(System.getenv(ECSConfigurationImpl.ECS_CLUSTER)) ||
            StringUtils.isBlank(System.getenv(ECSConfigurationImpl.ECS_TASK_DEF))) {
            throw new IllegalStateException("Environment variables " +
                    ECSConfigurationImpl.ECS_ASG + ", " +
                    ECSConfigurationImpl.ECS_CLUSTER + ", " +
                    ECSConfigurationImpl.ECS_TASK_DEF +  " are mandatory.");
        }
    }

    @Override
    public void initialize(Bootstrap<Configuration> bootstrap) {
        // Nothing here yet
    }

    @Override
    public void run(Configuration configuration,
                    Environment environment) {
        Injector injector = Guice.createInjector(new AbstractModule() {
            @Override
            protected void configure() {
                //system environment mapped to @Named, sort of shortcut
                Map<String, String> props = new HashMap<>(System.getenv());
                if (!props.containsKey(ECSConfigurationImpl.ECS_LOG_DRIVER)) {
                    props.put(ECSConfigurationImpl.ECS_LOG_DRIVER, "");
                }
                if (!props.containsKey(ECSConfigurationImpl.ECS_LOG_OPTIONS)) {
                    props.put(ECSConfigurationImpl.ECS_LOG_OPTIONS, "");
                }
                String ddApi = System.getenv(DatadogEventPublisher.DATADOG_API);
                if (ddApi != null) {
                    props.put(DatadogEventPublisher.DATADOG_API, ddApi);
                    bind(EventPublisher.class).to(DatadogEventPublisher.class);
                } else {
                    bind(EventPublisher.class).to(DummyEventPublisher.class);
                }
                bind(ECSConfiguration.class).to(ECSConfigurationImpl.class);
                bind(ECSScheduler.class).to(CyclingECSScheduler.class);
                bind(SchedulerBackend.class).to(AWSSchedulerBackend.class);
                bind(ModelLoader.class).to(AwsPullModelLoader.class);
                bind(ModelUpdater.class).to(DefaultModelUpdater.class);
                bind(TaskDefinitionRegistrations.Backend.class).to(ECSConfigurationImpl.class);

                Names.bindProperties(binder(), props);
            }
        });
        //make sure to close datadog before stopping.
        environment.lifecycle().addLifeCycleListener(new AbstractLifeCycle.AbstractLifeCycleListener() {
            @Override
            public void lifeCycleStopping(LifeCycle event) {
                EventPublisher ep = injector.getInstance(EventPublisher.class);
                if (ep instanceof Closeable) {
                    try {
                        ((Closeable) ep).close();
                    } catch (IOException ex) {
                    }
                }
            }
        });

        environment.jersey().register(injector.getInstance(SchedulerResource.class));
        environment.jersey().register(injector.getInstance(HeartBeatResource.class));
        environment.jersey().register(injector.getInstance(LogsResource.class));
    }
}