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*
* 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.
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*/
package org.apache.airavata.gfac;
import java.io.File;
import java.io.IOException;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.xpath.XPathExpressionException;
import org.apache.airavata.client.api.AiravataAPI;
import org.apache.airavata.client.api.exception.AiravataAPIInvocationException;
import org.apache.airavata.commons.gfac.type.ApplicationDescription;
import org.apache.airavata.commons.gfac.type.HostDescription;
import org.apache.airavata.gfac.core.context.JobExecutionContext;
import org.apache.airavata.gfac.core.provider.GFacProvider;
import org.apache.airavata.gfac.core.provider.GFacProviderConfig;
import org.apache.airavata.gfac.core.provider.GFacProviderException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.w3c.dom.Document;
import org.xml.sax.SAXException;
/**
* Scheduler decides the execution order of handlers based on application description. In addition
* to that scheduler decides which provider to invoke at the end. Scheduler will set
* provider instance and in/out handler chains in JobExecutionContext.
*/
public class Scheduler {
private static Logger log = LoggerFactory.getLogger(Scheduler.class);
/**
* Decide which provider to use and execution sequence of handlers based on job request and
* job configuration.
* @param jobExecutionContext containing job request as well as all the configurations.
*/
public static void schedule(JobExecutionContext jobExecutionContext) throws GFacException{
// Current implementation only support static handler sequence.
jobExecutionContext.setProvider(getProvider(jobExecutionContext));
// TODO: Selecting the provider based on application description.
jobExecutionContext.getGFacConfiguration().setInHandlers(jobExecutionContext.getProvider().getClass().getName(),
jobExecutionContext.getServiceName());
jobExecutionContext.getGFacConfiguration().setOutHandlers(jobExecutionContext.getProvider().getClass().getName(),
jobExecutionContext.getServiceName());
jobExecutionContext.getGFacConfiguration().setExecutionMode(getExecutionMode(jobExecutionContext));
}
/**
* Figure out which provider to use based on application configuration.
* @param jobExecutionContext containing all the required configurations.
* @return GFacProvider instance.
*/
private static GFacProvider getProvider(JobExecutionContext jobExecutionContext) throws GFacException {
HostDescription hostDescription = jobExecutionContext.getApplicationContext().getHostDescription();
String applicationName = jobExecutionContext.getServiceName();
URL resource = Scheduler.class.getClassLoader().getResource(org.apache.airavata.common.utils.Constants.GFAC_CONFIG_XML);
DocumentBuilderFactory docBuilderFactory = DocumentBuilderFactory.newInstance();
DocumentBuilder docBuilder = null;
Document handlerDoc = null;
try {
docBuilder = docBuilderFactory.newDocumentBuilder();
handlerDoc = docBuilder.parse(new File(resource.getPath()));
} catch (ParserConfigurationException e) {
throw new GFacException(e);
} catch (SAXException e) {
throw new GFacException(e);
} catch (IOException e) {
throw new GFacException(e);
}
GFacProviderConfig s = null;
GFacProvider provider = null;
List<GFacProviderConfig> aClass = null;
String providerClassName = null;
try {
aClass = GFacConfiguration.getProviderConfig(handlerDoc,
Constants.XPATH_EXPR_APPLICATION_HANDLERS_START + applicationName + "']", Constants.GFAC_CONFIG_APPLICATION_NAME_ATTRIBUTE);
// This should be have a single element only.
if (aClass != null && !aClass.isEmpty()) {
s = aClass.get(0);
Class<? extends GFacProvider> aClass1 = Class.forName(s.getClassName()).asSubclass(GFacProvider.class);
provider = aClass1.newInstance();
//loading the provider properties
if(!aClass.isEmpty()){
provider.initProperties(aClass.get(0).getProperties());
}
}
// We give higher preference to applications specific provider if configured
if (provider == null) {
String hostClass = hostDescription.getType().getClass().getName();
providerClassName = GFacConfiguration.getAttributeValue(GFacConfiguration.getHandlerDoc(), Constants.XPATH_EXPR_PROVIDER_ON_HOST + hostClass + "']", Constants.GFAC_CONFIG_CLASS_ATTRIBUTE);
Class<? extends GFacProvider> aClass1 = Class.forName(providerClassName).asSubclass(GFacProvider.class);
provider = aClass1.newInstance();
//loading the provider properties
aClass = GFacConfiguration.getProviderConfig(GFacConfiguration.getHandlerDoc(), Constants.XPATH_EXPR_PROVIDER_HANDLERS_START +
providerClassName + "']", Constants.GFAC_CONFIG_APPLICATION_NAME_ATTRIBUTE);
if(!aClass.isEmpty()){
provider.initProperties(aClass.get(0).getProperties());
}
}
} catch (XPathExpressionException e) {
log.error("Error evaluating XPath expression"); //To change body of catch statement use File | Settings | File Templates.
throw new GFacException("Error evaluating XPath expression", e);
} catch (GFacProviderException e) {
log.error("Error During scheduling"); //To change body of catch statement use File | Settings | File Templates.
throw new GFacException("Error During scheduling", e);
}catch (ClassNotFoundException e) {
log.error("Application Provider class: " + s + "couldn't find");
throw new GFacException("Error initializing application specific Handler: " +providerClassName , e);
} catch (InstantiationException e) {
log.error("Error initializing application specific Handler: " + providerClassName);
throw new GFacException("Error initializing Handler", e);
} catch (IllegalAccessException e) {
log.error("Error initializing application specific Handler: " + providerClassName);
throw new GFacException("Error initializing Handler", e);
}
return provider;
}
public static ExecutionMode getExecutionMode(JobExecutionContext jobExecutionContext)throws GFacException{
HostDescription hostDescription = jobExecutionContext.getApplicationContext().getHostDescription();
String applicationName = jobExecutionContext.getServiceName();
URL resource = Scheduler.class.getClassLoader().getResource(org.apache.airavata.common.utils.Constants.GFAC_CONFIG_XML);
DocumentBuilderFactory docBuilderFactory = DocumentBuilderFactory.newInstance();
DocumentBuilder docBuilder = null;
Document handlerDoc = null;
try {
docBuilder = docBuilderFactory.newDocumentBuilder();
handlerDoc = docBuilder.parse(new File(resource.getPath()));
} catch (ParserConfigurationException e) {
throw new GFacException(e);
} catch (SAXException e) {
throw new GFacException(e);
} catch (IOException e) {
throw new GFacException(e);
}
GFacProviderConfig s = null;
String executionMode = "sync";
try {
executionMode = GFacConfiguration.getAttributeValue(handlerDoc,
Constants.XPATH_EXPR_APPLICATION_HANDLERS_START + applicationName + "']", Constants.GFAC_CONFIG_EXECUTION_MODE_ATTRIBUTE);
// This should be have a single element only.
if (executionMode == null || "".equals(executionMode)) {
String hostClass = hostDescription.getType().getClass().getName();
executionMode = GFacConfiguration.getAttributeValue(GFacConfiguration.getHandlerDoc(), Constants.XPATH_EXPR_PROVIDER_ON_HOST + hostClass + "']", Constants.GFAC_CONFIG_EXECUTION_MODE_ATTRIBUTE);
}
} catch (XPathExpressionException e) {
log.error("Error evaluating XPath expression"); //To change body of catch statement use File | Settings | File Templates.
throw new GFacException("Error evaluating XPath expression", e);
}
return ExecutionMode.fromString(executionMode);
}
public static HostDescription pickaHost(AiravataAPI api, String serviceName) throws AiravataAPIInvocationException {
List<HostDescription> registeredHosts = new ArrayList<HostDescription>();
Map<String, ApplicationDescription> applicationDescriptors = api.getApplicationManager().getApplicationDescriptors(serviceName);
for (String hostDescName : applicationDescriptors.keySet()) {
registeredHosts.add(api.getApplicationManager().getHostDescription(hostDescName));
}
return scheduleHost(registeredHosts);
}
private static HostDescription scheduleHost(List<HostDescription> registeredHosts) {
//todo implement an algorithm to pick a host among different hosts, ideally this could be configurable in an xml
return registeredHosts.get(0);
}
}