Built-In Workflow Events — Workflow Event Bus

Event Reference

Event Class	When Published	Key Payload Fields
`WorkflowStarted`	Execution begins (first node queued)	ExecutionId, ProcessId, TenantId, TriggeredBy, StartedAt
`WorkflowCompleted`	All nodes finished successfully	ExecutionId, ProcessId, TenantId, DurationMs, CompletedAt
`WorkflowFailed`	A node threw an unrecoverable error	ExecutionId, ProcessId, TenantId, FailedNodeId, Error, FailedAt
`WorkflowPaused`	A HIL node suspended the execution	ExecutionId, ProcessId, TenantId, SuspendedNodeId, SuspendedAt
`WorkflowResumed`	A HIL resume call restarted execution	ExecutionId, ProcessId, TenantId, ResumedAt, ResumedBy

WorkflowStarted

public class WorkflowStarted : WorkflowEvent
{
    public string TriggeredBy { get; init; }  // userId or "system"
    public DateTimeOffset StartedAt { get; init; }
    public Dictionary<string, object>? TriggerPayload { get; init; }
}

WorkflowCompleted

public class WorkflowCompleted : WorkflowEvent
{
    public long DurationMs   { get; init; }
    public DateTimeOffset CompletedAt { get; init; }
    public WorkflowStatus Status { get; init; }  // Success
}

WorkflowFailed

public class WorkflowFailed : WorkflowEvent
{
    public string FailedNodeId   { get; init; }
    public string FailedNodeType { get; init; }
    public string ErrorMessage   { get; init; }
    public string? ErrorType     { get; init; }
    public DateTimeOffset FailedAt { get; init; }
}

WorkflowPaused

public class WorkflowPaused : WorkflowEvent
{
    public string SuspendedNodeId   { get; init; }
    public string CorrelationToken  { get; init; }
    public string ActorId           { get; init; }
    public DateTimeOffset SuspendedAt { get; init; }
    public DateTimeOffset? ExpiresAt  { get; init; }
}

WorkflowResumed

public class WorkflowResumed : WorkflowEvent
{
    public string ResumedBy         { get; init; }  // userId who responded
    public string CorrelationToken  { get; init; }
    public DateTimeOffset ResumedAt { get; init; }
}

Subscribing to a Built-In Event (Example)

// Handler: send a webhook when a workflow completes or fails
public class WorkflowWebhookHandler :
    IWorkflowEventHandler<WorkflowCompleted>,
    IWorkflowEventHandler<WorkflowFailed>
{
    private readonly IWebhookService _webhooks;

    public WorkflowWebhookHandler(IWebhookService webhooks) => _webhooks = webhooks;

    public async Task HandleAsync(WorkflowCompleted @event, CancellationToken ct)
    {
        await _webhooks.DeliverAsync(@event.ProcessId, "completed", new
        {
            executionId = @event.ExecutionId,
            durationMs  = @event.DurationMs,
            status      = "success"
        }, ct);
    }

    public async Task HandleAsync(WorkflowFailed @event, CancellationToken ct)
    {
        await _webhooks.DeliverAsync(@event.ProcessId, "failed", new
        {
            executionId  = @event.ExecutionId,
            failedNode   = @event.FailedNodeId,
            errorMessage = @event.ErrorMessage
        }, ct);
    }
}

// Registration (both event types, same handler class)
services.AddTransient<IWorkflowEventHandler<WorkflowCompleted>, WorkflowWebhookHandler>();
services.AddTransient<IWorkflowEventHandler<WorkflowFailed>,    WorkflowWebhookHandler>();

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