{"id":22668,"date":"2015-07-08T17:34:44","date_gmt":"2015-07-08T12:04:44","guid":{"rendered":"http:\/\/www.tothenew.com\/blog\/?p=22668"},"modified":"2016-12-19T15:02:50","modified_gmt":"2016-12-19T09:32:50","slug":"aem-robust-sling-eventing-using-sling-jobs","status":"publish","type":"post","link":"https:\/\/www.tothenew.com\/blog\/aem-robust-sling-eventing-using-sling-jobs\/","title":{"rendered":"AEM : Robust Sling Eventing using Sling Jobs"},"content":{"rendered":"

So far we have\u00a0used OSGi Event Admin<\/a> for event publishing that uses publisher subscriber model. Though it works really well, there is\u00a0a downside in using this:<\/p>\n

– No guarantee of delivery<\/p>\n

As soon as an event is published, job of the publisher is done. No matter whether any subscriber has worked on it or not, the event just dies down.<\/p>\n

– No distributed delivery<\/p>\n

OSGi Event Admin doesn’t fare well with clustered environment.<\/p>\n

Sling Job mechanism takes care of these shortcomings and is persistent(persisted under\u00a0\/var\/eventing\/jobs). It guarantees delivery and comes with lots of configurable options like number of retries and retry interval. In AEM 6.1 release notes<\/a>, Adobe recommends using this new Eventing mechanism as old eventing has deprecated.<\/p>\n

To implement it, you need a publisher and a consumer:<\/p>\n

Publisher makes use of JobManager to add a job:<\/p>\n

[java]
\n@Reference
\nprivate JobManager jobManager;<\/p>\n

@Override
\npublic void publishJob() {
\n final Map<String, Object> jobProperties = new HashMap<String, Object>();
\n jobProperties.put("jobName", "some dummy job");
\n jobProperties.put("count", 3);
\n jobProperties.put("job location", "yet another city");
\n jobManager.addJob("my\/sling\/job", jobProperties);
\n}
\n[\/java]<\/p>\n

Here addJob method takes 2 parameters(same as event service) – job topic and properties.<\/p>\n

Consumer subscribes to that job topic and processes it. In case of successful execution<\/a>, JobResult.OK should be returned. In case there is some issue in execution but you need to keep job for retry, use JobResult.FAILED, else use JobResult.CANCEL that cancels the job right away.<\/p>\n

[java]
\n@Component
\n@Service(value={JobConsumer.class})
\n@Property(name=JobConsumer.PROPERTY_TOPICS, value="my\/sling\/job")
\npublic class MyJobConsumer implements JobConsumer {<\/p>\n

public JobResult process(final Job job) {
\n System.out.println("==========================================");
\n System.out.println(job.getProperty("count"));
\n System.out.println("==========================================");
\n \/\/ process the job and return the result
\n int count = (Integer)job.getProperty("count");
\n if(count > 3){
\n return JobResult.FAILED;
\n }
\n return JobResult.OK;
\n }
\n}
\n[\/java]<\/p>\n

“Apache Sling Default Job Queue” maintains default configuration of the queue. \u00a0We can also maintain a separate queue for a pool of job topics that we create. \u00a0“Apache Sling Job Queue Configuration” is a factory configuration that takes care of this.<\/p>\n

\"queue\"<\/p>\n

Hope this helps.. \ud83d\ude42<\/p>\n

Vivek Sachdeva<\/p>\n

Github Repo<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

So far we have\u00a0used OSGi Event Admin for event publishing that uses publisher subscriber model. Though it works really well, there is\u00a0a downside in using this: – No guarantee of delivery As soon as an event is published, job of the publisher is done. No matter whether any subscriber has worked on it or not, […]<\/p>\n","protected":false},"author":48,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"iawp_total_views":123,"footnotes":""},"categories":[1],"tags":[1581,1971,4850,1521,1970],"class_list":["post-22668","post","type-post","status-publish","format-standard","hentry","category-technology","tag-aem6","tag-eventing","tag-osgi","tag-sling","tag-sling-job"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t