content-distribution

backendadobe

AEM as a Cloud Service content distribution and replication. Covers programmatic publishing using the Replication API and distribution event monitoring using Sling Distribution events.

Install

npx skills add https://github.com/adobe/skills --skill content-distribution

SKILL.md

---name: content-distributionlicense: Apache-2.0description: |---

AEM Cloud Service Content Distribution

Beta Skill: This skill is in beta and under active development. Results should be reviewed carefully before use in production. Report issues at https://github.com/adobe/skills/issues

Programmatic content publishing and distribution monitoring using official AEM Cloud Service APIs.

When to Use This Skill

Use this skill collection for:

Programmatic publishing: Publish content via Replicator API
Distribution monitoring: Track distribution lifecycle events
Automated workflows: Integration with workflow process steps
Event handling: React to distribution events (failures, completions)
Custom publishing logic: Bulk operations, Preview tier publishing

Sub-Skills

This is a parent skill that routes to specialized sub-skills based on your task:

Task	Sub-Skill	File
Programmatically publish/unpublish content	Replication API	replication/SKILL.md
Monitor distribution events and lifecycle	Sling Distribution Events	sling-distribution/SKILL.md

Quick Decision Guide

Choose Replication API when you need to:

Publish content from custom OSGi services
Integrate publishing into workflow steps
Perform bulk publishing operations
Publish to Preview tier for review
Check replication status programmatically

Choose Sling Distribution Events when you need to:

Monitor distribution lifecycle (created, queued, distributed, imported)
React to distribution failures
Trigger post-distribution actions (cache warming, notifications)
Audit distribution operations
Track distribution metrics

Official APIs

Both skills use official, supported AEM Cloud Service APIs:

Replication API: com.day.cq.replication
- Javadoc: https://developer.adobe.com/experience-manager/reference-materials/cloud-service/javadoc/com/day/cq/replication/package-summary.html
- Main Classes: Replicator, ReplicationOptions, ReplicationStatus, ReplicationActionType
Sling Distribution API: org.apache.sling.distribution
- Javadoc: https://developer.adobe.com/experience-manager/reference-materials/cloud-service/javadoc/org/apache/sling/distribution/package-summary.html
- Main Packages: org.apache.sling.distribution.event (event topics and properties)

Architecture Overview

┌──────────────────────────────────────────────────┐
│ Replication API (Your Code)                     │
│ com.day.cq.replication.Replicator                │
│                                                  │
│ replicator.replicate(session, ACTIVATE, path)   │
└────────────────────┬─────────────────────────────┘
                     ↓
┌──────────────────────────────────────────────────┐
│ Sling Distribution (Underlying Transport)       │
│ org.apache.sling.distribution                    │
│                                                  │
│ [AGENT_PACKAGE_CREATED]   ← Distribution events │
│          ↓                   fire at each stage  │
│ [AGENT_PACKAGE_QUEUED]                          │
│          ↓                                       │
│ [AGENT_PACKAGE_DISTRIBUTED]                     │
│          ↓                                       │
│ Adobe Developer Pipeline Service                │
│          ↓                                       │
│ [IMPORTER_PACKAGE_IMPORTED]                     │
└──────────────────────────────────────────────────┘
                     ↓
         Content live on Publish/Preview

How It Works

Your code calls Replicator.replicate() to publish content
Sling Distribution packages content and fires AGENT_PACKAGE_CREATED event
Package is queued and AGENT_PACKAGE_QUEUED event fires
Package is sent to Adobe Developer pipeline and AGENT_PACKAGE_DISTRIBUTED event fires
Target tier imports content and IMPORTER_PACKAGE_IMPORTED event fires
Content is live on target tier (Publish or Preview)

Common Patterns

Pattern 1: Publish and Monitor

Publish content and track when it goes live:

// Step 1: Publish using Replication API
@Reference
private Replicator replicator;

public void publishContent(Session session, String path) throws ReplicationException {
    replicator.replicate(session, ReplicationActionType.ACTIVATE, path);
}

// Step 2: Monitor completion using Distribution Events
@Component(service = EventHandler.class, property = {
    org.osgi.service.event.EventConstants.EVENT_TOPIC + "=" + 
        DistributionEventTopics.IMPORTER_PACKAGE_IMPORTED
})
public class PublishCompletionHandler implements EventHandler {
    
    @Override
    public void handleEvent(Event event) {
        String[] paths = (String[]) event.getProperty(
            DistributionEventProperties.DISTRIBUTION_PATHS
        );
        
        LOG.info("Content is now live: {}", String.join(",", paths));
        // Trigger post-publish actions (cache warming, notifications, etc.)
    }
}

Pattern 2: Preview-First Workflow

Publish to Preview for approval, then to Publish:

// Workflow Step 1: Publish to Preview
public void publishToPreview(Session session, String path) throws ReplicationException {
    ReplicationOptions options = new ReplicationOptions();
    options.setFilter(agent -> "preview".equals(agent.getId()));
    
    replicator.replicate(session, ReplicationActionType.ACTIVATE, path, options);
}

// Workflow Step 2: After approval, publish to Publish tier
public void publishToProduction(Session session, String path) throws ReplicationException {
    ReplicationOptions options = new ReplicationOptions();
    options.setFilter(agent -> "publish".equals(agent.getId()));
    
    replicator.replicate(session, ReplicationActionType.ACTIVATE, path, options);
}

Pattern 3: Auto-Publish with Failure Handling

Auto-publish content and alert on failures:

// Publish handler
@Component(service = EventHandler.class, property = {
    org.osgi.service.event.EventConstants.EVENT_TOPIC + "=" + 
        SlingConstants.TOPIC_RESOURCE_CHANGED
})
public class AutoPublishHandler implements EventHandler {
    
    @Reference
    private Replicator replicator;
    
    @Override
    public void handleEvent(Event event) {
        String path = (String) event.getProperty(SlingConstants.PROPERTY_PATH);
        
        if (shouldAutoPublish(path)) {
            try (ResourceResolver resolver = getServiceResolver()) {
                Session session = resolver.adaptTo(Session.class);
                replicator.replicate(session, ReplicationActionType.ACTIVATE, path);
            } catch (Exception e) {
                LOG.error("Auto-publish failed", e);
            }
        }
    }
}

// Failure monitoring
@Component(service = EventHandler.class, property = {
    org.osgi.service.event.EventConstants.EVENT_TOPIC + "=" + 
        DistributionEventTopics.AGENT_PACKAGE_DROPPED
})
public class FailureAlertHandler implements EventHandler {
    
    @Reference
    private AlertService alertService;
    
    @Override
    public void handleEvent(Event event) {
        String packageId = (String) event.getProperty(
            DistributionEventProperties.DISTRIBUTION_PACKAGE_ID
        );
        
        alertService.sendAlert("Distribution failed", packageId);
    }
}

Rate Limits and Constraints

Constraint	Limit	Impact
Paths per API call (recommended)	100	Transactional guarantee; system auto-splits above this
Payload size	10 MB	Excluding binaries

Note: ReplicationOptions.setUseAtomicCalls() is @Deprecated / "no longer required" per the Cloud Service Javadoc — the system handles auto-bucketing automatically for >100 paths.

Best Practice: For large hierarchical content trees, use the Tree Activation workflow step instead of custom code.

Key Differences from AEM 6.x

Feature	AEM 6.x	AEM Cloud Service
Replication API	`com.day.cq.replication.Replicator`	✅ Same API
Replication agents	Manual configuration	✅ Automatic (managed by Adobe)
Transport mechanism	Direct JCR replication	✅ Sling Distribution via Adobe pipeline
Preview tier	Not available	✅ Available (requires agent filtering)
Distribution events	Limited	✅ Full lifecycle via `org.apache.sling.distribution.event`
Agent configuration	Manual OSGi config	❌ Not exposed (managed by Adobe)

When NOT to Use These Skills

Use UI workflows instead when:

Publishing small amounts of content manually
One-off publishing operations
Content authors can use Quick Publish or Manage Publication

Use Tree Activation workflow when:

Publishing large hierarchical content trees
Bulk operations across hundreds of paths and no custom logic is needed

Quick Reference

Replication API Basics

// Inject service
@Reference
private Replicator replicator;

// Publish single page
replicator.replicate(session, ReplicationActionType.ACTIVATE, "/content/mysite/page");

// Unpublish
replicator.replicate(session, ReplicationActionType.DEACTIVATE, "/content/mysite/page");

// Bulk publish (≤100 for transactional guarantee)
replicator.replicate(session, ReplicationActionType.ACTIVATE, 
    new String[]{"/content/page1", "/content/page2"}, null);

// Publish to Preview
ReplicationOptions options = new ReplicationOptions();
options.setFilter(agent -> "preview".equals(agent.getId()));
replicator.replicate(session, ReplicationActionType.ACTIVATE, "/content/page", options);

// Check status
ReplicationStatus status = replicator.getReplicationStatus(session, "/content/page");
boolean isPublished = status != null && status.isActivated();

Distribution Event Handling Basics

// Listen for distribution events
@Component(service = EventHandler.class, property = {
    org.osgi.service.event.EventConstants.EVENT_TOPIC + "=" + 
        DistributionEventTopics.AGENT_PACKAGE_CREATED,
    org.osgi.service.event.EventConstants.EVENT_TOPIC + "=" + 
        DistributionEventTopics.AGENT_PACKAGE_DISTRIBUTED,
    org.osgi.service.event.EventConstants.EVENT_TOPIC + "=" + 
        DistributionEventTopics.AGENT_PACKAGE_DROPPED,
    org.osgi.service.event.EventConstants.EVENT_TOPIC + "=" + 
        DistributionEventTopics.IMPORTER_PACKAGE_IMPORTED
})
public class DistributionMonitor implements EventHandler {
    
    @Override
    public void handleEvent(Event event) {
        String topic = event.getTopic();
        String packageId = (String) event.getProperty(
            DistributionEventProperties.DISTRIBUTION_PACKAGE_ID
        );
        String[] paths = (String[]) event.getProperty(
            DistributionEventProperties.DISTRIBUTION_PATHS
        );
        
        // Handle event based on topic
        if (DistributionEventTopics.AGENT_PACKAGE_DROPPED.equals(topic)) {
            LOG.error("Distribution failed: {}", packageId);
        } else if (DistributionEventTopics.IMPORTER_PACKAGE_IMPORTED.equals(topic)) {
            LOG.info("Content is live: {}", String.join(",", paths));
        }
    }
}

Best Practices

Use the right API: Replication API for publishing, Distribution events for monitoring
Respect rate limits: ≤100 paths for transactional guarantee
Handle failures: Always catch ReplicationException, monitor AGENT_PACKAGE_DROPPED events
Use service users: Never use admin credentials
Filter events appropriately: Only listen to events you need
Validate permissions: Call replicator.checkPermission() before replication
Publish only what's needed: Avoid unnecessary bulk operations

Troubleshooting

Replication Issues

Issue	Solution
`ReplicationException`	Check service user has `crx:replicate` permission
Content not on target tier	Verify agent filter, check replication status
"Too many paths" error	Use ≤100 paths for transactional guarantee, or pass all paths — system auto-splits

Event Handling Issues

Issue	Solution
Event handler not firing	Verify event topic constant matches exactly
Missing event properties	Always null-check event properties
Handler slowing distribution	Use async job processing, don't block

Detailed Documentation

For detailed examples, code samples, and advanced usage:

Replication API: See replication/SKILL.md
Sling Distribution Events: See sling-distribution/SKILL.md

References

Replication Javadoc: https://developer.adobe.com/experience-manager/reference-materials/cloud-service/javadoc/com/day/cq/replication/package-summary.html
Sling Distribution Javadoc: https://developer.adobe.com/experience-manager/reference-materials/cloud-service/javadoc/org/apache/sling/distribution/package-summary.html
Adobe Documentation: https://experienceleague.adobe.com/docs/experience-manager-cloud-service/content/operations/replication.html
Sling Distribution: https://sling.apache.org/documentation/bundles/content-distribution.html
Service Users / Repo Init: https://experienceleague.adobe.com/en/docs/experience-manager-cloud-service/content/implementing/developing/aem-project-content-package-structure#repo-init