adobe/workflow-development

Workflow Development (Cloud Service)

Implement custom workflow components for AEM Cloud Service: WorkflowProcess, ParticipantStepChooser, OSGi registration, metadata handling, and error patterns.

Variant Scope

• AEM Cloud Service only.
• Use OSGi DS R6 annotations (org.osgi.service.component.annotations.*). Do not use Felix SCR.
• Bundle goes into the ui.apps content package and is deployed via Cloud Manager pipeline.

Workflow

Development Progress
- [ ] 1) Identify what the step does: process (auto) or participant (human) or dynamic participant
- [ ] 2) Create Java class implementing WorkflowProcess or ParticipantStepChooser
- [ ] 3) Register with correct @Component annotation and service property (process.label / chooser.label)
- [ ] 4) Read step arguments from MetaDataMap args (set in model editor)
- [ ] 5) Access payload via item.getWorkflowData().getPayload().toString()
- [ ] 6) Read/write workflow instance metadata via item.getWorkflowData().getMetaDataMap()
- [ ] 7) Return normally to advance; throw WorkflowException to trigger retry
- [ ] 8) Deploy bundle; verify process.label appears in Workflow Model Editor step picker

WorkflowProcess Template (Cloud Service)

@Component(
    service = WorkflowProcess.class,
    property = {
        "process.label=My Custom Process Step",
        "service.description=Short description of what this step does"
    }
)
public class MyCustomProcess implements WorkflowProcess {

    private static final Logger LOG = LoggerFactory.getLogger(MyCustomProcess.class);

    @Reference
    private ResourceResolverFactory resolverFactory;

    @Override
    public void execute(WorkItem item, WorkflowSession session, MetaDataMap args)
            throws WorkflowException {
        // 1. Read payload
        WorkflowData data = item.getWorkflowData();
        String payloadPath = data.getPayload().toString();

        // 2. Read step arguments
        String recipient = args.get("recipient", "workflow-administrators");
        boolean createVersion = args.get("createVersion", false);

        // 3. Read/write shared workflow metadata
        MetaDataMap metadata = data.getMetaDataMap();
        String status = metadata.get("approvalStatus", "PENDING");
        metadata.put("processedBy", "my-custom-step");

        // 4. Access JCR if needed
        try {
            ResourceResolver resolver = session.adaptTo(ResourceResolver.class);
            Resource resource = resolver.getResource(payloadPath);
            // ... do work ...
        } catch (Exception e) {
            LOG.error("Error in MyCustomProcess for payload {}", payloadPath, e);
            throw new WorkflowException("Failed: " + e.getMessage(), e);
        }
        // Return normally = step completes, workflow advances
    }
}

ParticipantStepChooser Template

@Component(
    service = ParticipantStepChooser.class,
    property = {"chooser.label=Content Owner Chooser"}
)
public class ContentOwnerChooser implements ParticipantStepChooser {

    @Override
    public String getParticipant(WorkItem workItem, WorkflowSession session,
                                 MetaDataMap args) throws WorkflowException {
        String payloadPath = workItem.getWorkflowData().getPayload().toString();
        try {
            Session jcrSession = session.adaptTo(Session.class);
            Node content = jcrSession.getNode(payloadPath + "/jcr:content");
            if (content.hasProperty("cq:lastModifiedBy")) {
                return content.getProperty("cq:lastModifiedBy").getString();
            }
        } catch (RepositoryException e) {
            throw new WorkflowException("Cannot resolve participant", e);
        }
        return args.get("fallbackParticipant", "content-authors");
    }
}

Guardrails

• Never use ResourceResolverFactory.loginAdministrative(). Always use a service user sub-service.
• Do not call Session.save() on the workflow session's JCR session for payload changes — use a separate ResourceResolver obtained from resolverFactory.getServiceResourceResolver().
• If a step must hold (not auto-advance), set PROCESS_AUTO_ADVANCE=false in the model metaData and use TaskWorkflowProcess or an external completion mechanism.

References

• process-step-patterns.md — WorkflowProcess patterns: payload access, metadata, error handling
• participant-step-patterns.md — ParticipantStepChooser patterns and completing participant steps
• variables-and-metadata.md — MetaDataMap, workflow variables, inter-step data
• api-reference.md
• cloud-service-guardrails.md