Weird spring boot scheduler behavior - don't work with lazy initialization - spring

I have bizarre scheduler behavior in my spring boot application. I run SB 2.6.7 and java 17.
My code
#Configuration
#EnableScheduling
public class SchedulingConfigurerConfiguration implements SchedulingConfigurer {
#Value("${schedule.pool}")
private int DYNO_CORES;
#Override
public void configureTasks(ScheduledTaskRegistrar taskRegistrar) {
var taskScheduler = new ThreadPoolTaskScheduler();
taskScheduler.setPoolSize(DYNO_CORES * 4);
taskScheduler.initialize();
taskRegistrar.setTaskScheduler(taskScheduler);
}
#Bean
SimpleAsyncTaskExecutor executor() {
var executor = new SimpleAsyncTaskExecutor("bg_tasks_");
executor.setConcurrencyLimit(UNBOUNDED_CONCURRENCY);//these jobs are mainly IO-bound, so let's not set a limit for now
return executor;
}
}
And my class with one task.
#Slf4j
#Service
public class NoPrimaryServiceTasks {
#Scheduled(fixedDelay = 1000, initialDelay = 1000 )
public void checkBacklogSize() {
log.info("logzzz");
}
}
And it doesn't work.
But when I paste context.getBean(NoPrimaryServiceTasks.class); in main method everything works.
How to solve it without this workaround?
org.springframework.boot.autoconfigure.task.ScheduledBeanLazyInitializationExcludeFilter - also this class doesn't work

someone added into our codebase this code :)
for ( String name : beanFactory.getBeanDefinitionNames() ) {
beanFactory.getBeanDefinition( name ).setLazyInit( true );
}

Related

Comparison of Guice and(move to) Spring

Could someone give me advice, please, how to re-write some method using simple Spring (w/o Boot)?
Here I have some code methods:
1. createInjector
private Injector injector;
someMethod(){
injector = Guice.createInjector(new ExampleClass1(), new ExampleClass2());}
2 setModules(Modules.override
setModules(Modules.override(new ExampleClass3()).with(new ExampleClass4()));
//////////////////////////////////////////////////////////////////
public static void setModules(Module... modules) {
initInjector(modules);
}
private static void initInjector(Module... modules) {
injector = Guice.createInjector(modules);
}
}
Taking the risk that my answer is too general.
Roughly saying you can think Guice modules as equivalent a configuration class with #Configuration annotation, that contains #Bean etc.
The Guice injector can be considered as equivalent to the Spring ApplicationContext.
So for example if we have two configuration files:
#Configuration
public class ConfigA {
#Bean
ExampleClass1 exampleClass1(){
return new ExampleClass1();
}
#Bean
ExampleClass2 exampleClass2(){
return new ExampleClass2();
}
}
#Configuration
public class ConfigB {
#Bean
ExampleClass1 exampleClass1(){
return new ExampleClass1();
}
#Bean
ExampleClass3 exampleClass2(){
return new ExampleClass3();
}
}
And Services ExampleClass4 that you want as alternative of ExampleClass3.
You may use the #Primary annotation
public class ExampleClass4 extends ExampleClass3 {
#Override
public String toString() {
return "ExampleClass4{}";
}
}
#Configuration
public class ConfigC {
#Bean
#Primary
ExampleClass3 exampleClass3(){
return new ExampleClass4();
}
}
So rewriting the app to Spring (core 5.2, not Spring boot) will be:
public class App {
public static void main(String[] args) {
AnnotationConfigApplicationContext ap = initAppContext();
overrideBinding(ap);
System.out.println(ap.getBean(ExampleClass3.class));
//prints ExampleClass4{}
}
private static AnnotationConfigApplicationContext initAppContext() {
AnnotationConfigApplicationContext ap = new AnnotationConfigApplicationContext();
ap.register(ConfigA.class, ConfigB.class);
return ap;
}
private static void overrideBinding(AnnotationConfigApplicationContext ap) {
ap.register(ConfigC.class);
ap.refresh();
}
}
This technic of overriding a binding will work only because ExampleClass3 wasn't defined as primary, if it doesn't that would not work and you need to consider a different approach.
For more information:
https://www.baeldung.com/spring-application-context
https://docs.spring.io/spring-javaconfig/docs/1.0.0.m3/reference/html/modularizing-configurations.html
Override bean definition in java config

How to schedule a cron job in spring boot without using #Scheduled() annotation

In spring boot, can I schedule a spring job by not using #Scheduled annotation to a method?
I am working with spring job in the spring boot. I want to schedule a job by using cron expression, but without using #Scheduled(cron = " ") annotation to the method.
I know that I can schedule a job inside this method as below.
#Scheduled (cron = "0 10 10 10 * ?")
public void execute() {
/ * some job code * /
}
But I want it to be dynamic so that I can take a cron expression as input from the user and schedule it.
I came up with a working example since I found your question interesting and have been interested in this problem before. It's based entirely on the source code so I have no idea if it comes close to following best practice. Nonetheless, you may be able to tune it to your needs. FYI, you don't necessarily need to create a new ScheduledTaskRegistrar object - I figured that since your objective is a dynamic scheduler, you wouldn't be interested in defining your tasks purely in the overwritten method.
#SpringBootApplication
public class TaskScheduler implements SchedulingConfigurer, CommandLineRunner {
public static void main(String[] args){SpringApplication.run(TaskScheduler.class, args);}
List<CronTask> cronTasks;
#Override
public void run(String... args) throws Exception {
CronTask task = this.createCronTask(new Runnable() {
#Override
public void run() {
System.out.println(LocalDateTime.now());
}
}, "1/10 * * * * *");
ScheduledTaskRegistrar taskRegistrar = new ScheduledTaskRegistrar();
taskRegistrar.addCronTask(task);
configureTasks(taskRegistrar);
Thread.sleep(51);
taskRegistrar.destroy();
taskRegistrar = null;
ScheduledTaskRegistrar taskRegistrar2 = new ScheduledTaskRegistrar();
taskRegistrar2.addCronTask(task);
configureTasks(taskRegistrar2);
}
#Override
public void configureTasks(ScheduledTaskRegistrar taskRegistrar) {
// "Calls scheduleTasks() at bean construction time" - docs
taskRegistrar.afterPropertiesSet();
}
public CronTask createCronTask(Runnable action, String expression) {
return new CronTask(action, new CronTrigger(expression));
}
}
I have experience using cron jobs in Azure and other places. Programming in Java, I have typically used #Scheduled with fixed times just for the sake of simplicity. Hope this is useful to you though.
Here is my working example, If somebody wants to use TaskScheduler without using #Scheduled Annotation
#Configuration Class
#Configuration
public class SchedulerConfig implements SchedulingConfigurer {
final Logger LOGGER = LogManager.getLogger(SchedulerConfig.class);
#Override
public void configureTasks(ScheduledTaskRegistrar scheduledTaskRegistrar) {
LOGGER.debug("Creating Async Task Scheduler");
scheduledTaskRegistrar.setTaskScheduler(taskScheduler());
}
// This is mandatory otherwise it will to be able to find bean of
// taskScheduler. Without this it was giving runtime error says, can not find
// taskScheduler bean.
#Bean
public TaskScheduler taskScheduler() {
ThreadPoolTaskScheduler scheduler = new ThreadPoolTaskScheduler();
scheduler.setPoolSize(20); // Better to read it from property file.
scheduler.setThreadNamePrefix("ThreadScheduler-");
scheduler.initialize();
return scheduler;
}
}
Scheduler Class which is called from Application class.
#Component
public class MyTaskScheduler {
private TaskScheduler taskScheduler;
// Here we are auto-wiring taskScheduler, that's why need to create
// taskScheduler bean in configuration class
#Autowired
public void setScheduler(TaskScheduler scheduler) {
this.taskScheduler = scheduler;
}
public void schedule() {
taskScheduler.scheduleWithFixedDelay(new Runnable(){
#Override
public void run() {
System.out.println("I am running after every 1 second");
}
}, 1000);
}
}
If in any chance #Configuration annotation is not working so put #EnableConfigurationProperties at main running class.
Make sure that you put #EnableScheduling at Application class, so main runnable class will look like
#SpringBootApplication
#EnableScheduling
#EnableConfigurationProperties
public class MainApplication implements CommandLineRunner {
#Autowired
MyTaskScheduler myTaskScheduler;
public static void main(String[] args) {
final Logger logger = LogManager.getLogger(MainApplication.class);
SpringApplication.run(MainApplication.class, args);
logger.info("Application started");
}
#Override
public void run(String... args) throws Exception {
myTaskScheduler.schedule();
}
}
This answer is similar to the two previous ones, but is more compact because it leverages the scheduling registrar already provided in the application context:
#Configuration
#EnableScheduling
public class Schedule implements SchedulingConfigurer {
private final transient WorkflowTriggerService workflowTriggerService;
public Schedule(final WorkflowTriggerService workflowTriggerService) {
this.workflowTriggerService = workflowTriggerService;
}
#Override
public void configureTasks(final ScheduledTaskRegistrar taskRegistrar) {
for (final WorkflowTrigger trigger : workflowTriggerService.getWorkflowTriggersWithSchedules()) {
taskRegistrar.addCronTask(new WorkflowTask(trigger), trigger.getSchedule());
}
}
}
Each WorkflowTrigger returned by the service has its own cron schedule, and therefore allows dynamic registration of scheduled tasks that are not known at compilation time.

#RefreshScope stops #Scheduled task

I have a monitoring app wherein I am running a fixedRate task. This is pulling in a config parameter configured with Consul. I want to pull in updated configuration, so I added #RefreshScope. But as soon as I update the config value on Consul, the fixedRate task stops running.
#Service
#RefreshScope
public class MonitorService {
#Autowired
private AppConfig appConfig;
#PostConstruct
public void postConstRun() {
System.out.println(appConfig.getMonitorConfig());
}
#Scheduled(fixedRate = 1000)
public void scheduledMonitorScan() {
System.out.println("MonitorConfig:" + appConfig.getMonitorConfig());
}
}
AppConfig class just has a single String parameter:
#Configuration
#Getter
#Setter
public class AppConfig {
#Value("${monitor-config:default value}")
private String monitorConfig;
}
As soon as I update the value in consul, the scheduled task just stops running (display in sheduledMonitorScan method) stop showing up.
I'm successfully get & override the values from consul config server using RefreshScopeRefreshedEvent
import java.text.SimpleDateFormat;
import java.util.Date;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.cloud.context.config.annotation.RefreshScope;
import org.springframework.cloud.context.scope.refresh.RefreshScopeRefreshedEvent;
import org.springframework.context.ApplicationListener;
import org.springframework.scheduling.annotation.Scheduled;
import org.springframework.stereotype.Component;
#Component
#RefreshScope
public class AlertSchedulerCron implements ApplicationListener<RefreshScopeRefreshedEvent> {
private SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
#Value("${pollingtime}")
private String pollingtime;
/*
* #Value("${interval}") private String interval;
*/
#Scheduled(cron = "${pollingtime}")
//#Scheduled(fixedRateString = "${interval}" )
public void task() {
System.out.println(pollingtime);
System.out.println("Scheduler (cron expression) task with duration : " + sdf.format(new Date()));
}
#Override
public void onApplicationEvent(RefreshScopeRefreshedEvent event) {
// TODO Auto-generated method stub
}
}
Here's how we've solved this issue.
/**
* Listener of Spring's lifecycle to revive Scheduler beans, when spring's
* scope is refreshed.
* <p>
* Spring is able to restart beans, when we change their properties. Such a
* beans marked with RefreshScope annotation. To make it work, spring creates
* <b>lazy</b> proxies and push them instead of real object. The issue with
* scope refresh is that right after refresh in order for such a lazy proxy
* to be actually instantiated again someone has to call for any method of it.
* <p>
* It creates a tricky case with Schedulers, because there is no bean, which
* directly call anything on any Scheduler. Scheduler lifecycle is to start
* few threads upon instantiation and schedule tasks. No other bean needs
* anything from them.
* <p>
* To overcome this, we had to create artificial method on Schedulers and call
* them, when there is a scope refresh event. This actually instantiates.
*/
#RequiredArgsConstructor
public class RefreshScopeListener implements ApplicationListener<RefreshScopeRefreshedEvent> {
private final List<RefreshScheduler> refreshSchedulers;
#Override
public void onApplicationEvent(RefreshScopeRefreshedEvent event) {
refreshSchedulers.forEach(RefreshScheduler::materializeAfterRefresh);
}
}
So, we've defined an interface, which does nothing in particular, but allows us to call for a refreshed job.
public interface RefreshScheduler {
/**
* Used after refresh context for scheduler bean initialization
*/
default void materializeAfterRefresh() {
}
}
And here is actual job, whose parameter from.properties can be refreshed.
public class AJob implements RefreshScheduler {
#Scheduled(cron = "${from.properties}")
public void aTask() {
// do something useful
}
}
UPDATED:
Of course AJob bean must be marked with #RefreshScope in #Configuration
#Configuration
#EnableScheduling
public class SchedulingConfiguration {
#Bean
#RefreshScope
public AJob aJob() {
return new AJob();
}
}
I have done workaround for this kind of scenario by implementing SchedulingConfigurer interface.
Here I am dynamically updating "scheduler.interval" property from external property file and scheduler is working fine even after actuator refresh as I am not using #RefreshScope anymore.
Hope this might help you in your case also.
public class MySchedulerImpl implements SchedulingConfigurer {
#Autowired
private Environment env;
#Bean(destroyMethod = "shutdown")
public Executor taskExecutor() {
return Executors.newScheduledThreadPool(10);
}
#Override
public void configureTasks(final ScheduledTaskRegistrar taskRegistrar) {
taskRegistrar.setScheduler(this.taskExecutor());
taskRegistrar.addTriggerTask(() -> {
//put your code here that to be scheduled
}, triggerContext -> {
final Calendar nextExecutionTime = new GregorianCalendar();
final Date lastActualExecutionTime = triggerContext.lastActualExecutionTime();
if (lastActualExecutionTime == null) {
nextExecutionTime.setTime(new Date());
} else {
nextExecutionTime.setTime(lastActualExecutionTime);
nextExecutionTime.add(Calendar.MILLISECOND, env.getProperty("scheduler.interval", Integer.class));
}
return nextExecutionTime.getTime();
});
}
}
My solution consists of listening to EnvironmentChangeEvent
#Configuration
public class SchedulingSpringConfig implements ApplicationListener<EnvironmentChangeEvent>, SchedulingConfigurer {
private static final Logger LOGGER = LoggerFactory.getLogger(SchedulingSpringConfig.class);
private final DemoProperties demoProperties;
public SchedulingSpringConfig(DemoProperties demoProperties) {
this.demoProperties = demoProperties;
}
#Override
public void configureTasks(ScheduledTaskRegistrar taskRegistrar) {
LOGGER.info("Configuring scheduled task with cron expression: {}", demoProperties.getCronExpression());
taskRegistrar.addTriggerTask(triggerTask());
taskRegistrar.setTaskScheduler(taskScheduler());
}
#Bean
public TriggerTask triggerTask() {
return new TriggerTask(this::work, cronTrigger());
}
private void work() {
LOGGER.info("Doing work!");
}
#Bean
#RefreshScope
public CronTrigger cronTrigger() {
return new CronTrigger(demoProperties.getCronExpression());
}
#Bean
public ThreadPoolTaskScheduler taskScheduler() {
return new ThreadPoolTaskScheduler();
}
#Override
public void onApplicationEvent(EnvironmentChangeEvent event) {
if (event.getKeys().contains("demo.config.cronExpression")) {
ScheduledTasksRefresher scheduledTasksRefresher = new ScheduledTasksRefresher(triggerTask());
scheduledTasksRefresher.afterPropertiesSet();
}
}
}
Then I use the ContextLifecycleScheduledTaskRegistrar to recreate the task.
public class ScheduledTasksRefresher extends ContextLifecycleScheduledTaskRegistrar {
private final TriggerTask triggerTask;
ScheduledTasksRefresher(TriggerTask triggerTask) {
this.triggerTask = triggerTask;
}
#Override
public void afterPropertiesSet() {
super.destroy();
super.addTriggerTask(triggerTask);
super.afterSingletonsInstantiated();
}
}
Properties definition:
#ConfigurationProperties(prefix = "demo.config", ignoreUnknownFields = false)
public class DemoProperties {
private String cronExpression;
public String getCronExpression() {
return cronExpression;
}
public void setCronExpression(String cronExpression) {
this.cronExpression = cronExpression;
}
}
Main definition:
#SpringBootApplication
#EnableConfigurationProperties(DemoProperties.class)
#EnableScheduling
public class DemoApplication {
public static void main(String[] args) {
SpringApplication.run(DemoApplication.class, args);
}
}
Based on previous answers I added the following interface and used it on #RefreshScope annotated beans:
public interface RefreshScopeScheduled {
#EventListener(RefreshScopeRefreshedEvent.class)
default void onApplicationEvent() { /*do nothing*/ }
}

Spring : #Scheduled task triggered through the #Controller and Websocket

I have an #Scheduled task which send data to a client every sec throught a websocket.
My need is to start running my scheduled task only when the client ask for it.
Instead of, my task starts when my server starts. it's not the behavior i want.
currently, I have a bean of my scheduled task which is declared in my SchedulingConfigurer :
#Configuration
#EnableScheduling
public class SchedulingConfigurer implements org.springframework.scheduling.annotation.SchedulingConfigurer {
#Bean
public ThreadPoolTaskScheduler taskScheduler() {
return new ThreadPoolTaskScheduler();
}
#Bean
public ScheduledTask scheduledTask() {
return new ScheduledTask();
}
#Override
public void configureTasks(ScheduledTaskRegistrar taskRegistrar) {
taskRegistrar.setTaskScheduler(taskScheduler());
}
}
Here is my spring controller code :
#MessageMapping("/hello")
public void greeting() throws Exception {
//How do I start my scheduled task here ?
}
Maybe isn't possible to do that with #Scheduled annotation and i have to use the TaskScheduler interface ?
remove #Scheduled declaration from ScheduledTask class
implements Runnable interface instead of
#Component
//#Scope(ConfigurableBeanFactory.SCOPE_PROTOTYPE)
public class ScheduledTask implements Runnable {
private static final Logger log = LoggerFactory.getLogger(ScheduledTask.class);
private static final SimpleDateFormat dateFormat = new SimpleDateFormat("HH:mm:ss");
public void doWork() {
printMessage();
// TODO real work
}
private void printMessage() {
log.info("time to work: {}", dateFormat.format(new Date()));
}
#Override
public void run() {
doWork();
}
}
schedule Your task in controller area like this
#Controller
public class ScheduledTaskController {
#Autowired
private TaskScheduler taskScheduler;
#Autowired
private ScheduledTask scheduledTask;
#RequestMapping(value = "/task/run", method = RequestMethod.GET)
public String runTask() {
// start to run task every 5 sec.
taskScheduler.schedule(scheduledTask, new CronTrigger("0/5 * * * * ?"));
// ok, redirect
return "redirect:/task";
}
}
#Schedule is the declarative way, so not the point you're trying to achieve here.
You could create a Bean using one of the TaskScheduler implementations, such as ThreadPoolTaskScheduler and inject that bean in your application.
It has all the necessary methods to dynamically schedule tasks.

Spring MVC how to get progress of running async task

I would like to start an asynchronous task from within controller like in following code sniplet from Spring docs.
import org.springframework.core.task.TaskExecutor;
public class TaskExecutorExample {
private class MessagePrinterTask implements Runnable {
private int cn;
public MessagePrinterTask() {
}
public void run() {
//dummy code
for (int i = 0; i < 10; i++) {
cn = i;
}
}
}
private TaskExecutor taskExecutor;
public TaskExecutorExample(TaskExecutor taskExecutor) {
this.taskExecutor = taskExecutor;
}
public void printMessages() {
taskExecutor.execute(new MessagePrinterTask());
}
}
afterwards in annother request (in the case that task is running) I need to check the progress of the task. Basicaly get the value of cn.
What would be the best aproach in Spring MVC a how to avoid syncronisation issues.
Thanks
Pepa Procházka
Have you looked at the #Async annotation in the Spring reference doc?
First, create a bean for your asynchronous task:
#Service
public class AsyncServiceBean implements ServiceBean {
private AtomicInteger cn;
#Async
public void doSomething() {
// triggers the async task, which updates the cn status accordingly
}
public Integer getCn() {
return cn.get();
}
}
Next, call it from the controller:
#Controller
public class YourController {
private final ServiceBean bean;
#Autowired
YourController(ServiceBean bean) {
this.bean = bean;
}
#RequestMapping(value = "/trigger")
void triggerAsyncJob() {
bean.doSomething();
}
#RequestMapping(value = "/status")
#ResponseBody
Map<String, Integer> fetchStatus() {
return Collections.singletonMap("cn", bean.getCn());
}
}
Remember to configure an executor accordingly, e.g.
<task:annotation-driven executor="myExecutor"/>
<task:executor id="myExecutor" pool-size="5"/>
One solution could be: in your async thread, write to a DB, and have your checking code check the DB table for progress. You get the additional benefit of persisting performance data for later evaluation.
Also, just use the #Async annotation to kick off the asynchronous thread - makes life easier and is a Spring Way To Do It.
Check this github source, it gives pretty simple way of catching status of the background job using #Async of Spring mvc.
https://github.com/frenos/spring-mvc-async-progress/tree/master/src/main/java/de/codepotion/examples/asyncExample
Ignoring synchronization issues you could do something like this:
private class MessagePrinterTask implements Runnable {
private int cn;
public int getCN() {
return cn;
}
...
}
public class TaskExecutorExample {
MessagePrinterTask printerTask;
public void printMessages() {
printerTask = new MessagePrinterTask();
taskExecutor.execute(printerTask);
}
...
}

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