DataFlow Policies

Structure

public sealed class DataFlowPolicy
{
    public bool AcceptsUpstreamInput     { get; init; } = false;
    public bool EmitsToDownstream        { get; init; } = false;
    public bool PersistsToMemory         { get; init; } = false;
    public bool ExcludeFromInputMapping  { get; init; } = false;
    public bool ExcludeFromOutputMapping { get; init; } = false;
}

AcceptsUpstreamInput

When true, this field can receive its value from an upstream node's output. The platform's input mapper automatically populates the field from the incoming data bag.

EmitsToDownstream

When true, this field's value is included in the node's output data and can be consumed by downstream nodes.

PersistsToMemory

When true, the field's value is written to the workflow's persistent memory store after execution, available throughout the rest of the workflow lifetime.

Use when: The value must survive suspension/resumption cycles, is needed for audit, or other non-immediate downstream nodes may reference it.

ExcludeFromInputMapping

When true, this field is skipped by the automatic input mapper even if upstream data contains a matching key. The field can only be set via its own static config or expression evaluation.

Primary use case: Credentials and internal routing fields that must never be overwritten by upstream data regardless of name collisions.

// credentialId must never be overwritten by upstream
ExcludeFromInputMapping = true   // defensive — even though AcceptsUpstreamInput is false

ExcludeFromOutputMapping

When true, this field is not included in the node's output data bag sent to downstream nodes, even if EmitsToDownstream is set.

Use on all input/config fields to prevent them from leaking into downstream data.

Field Archetype Patterns

Static Config

Fixed in the workflow definition — does not flow in or out.

DataFlowPolicy = new DataFlowPolicy
{
    AcceptsUpstreamInput     = false,
    EmitsToDownstream        = false,
    PersistsToMemory         = false,
    ExcludeFromInputMapping  = true,
    ExcludeFromOutputMapping = true
}
// Examples: strategy, method, host, resource, operation

Dynamic Input

Receives its value from upstream nodes at runtime.

DataFlowPolicy = new DataFlowPolicy
{
    AcceptsUpstreamInput     = true,
    EmitsToDownstream        = false,
    PersistsToMemory         = false,
    ExcludeFromInputMapping  = false,
    ExcludeFromOutputMapping = true
}
// Examples: to, body, channel, actors, assignedTo

Output / Result

Produced by the executor; downstream nodes consume it.

DataFlowPolicy = new DataFlowPolicy
{
    AcceptsUpstreamInput     = false,
    EmitsToDownstream        = true,
    PersistsToMemory         = true,
    ExcludeFromInputMapping  = true,
    ExcludeFromOutputMapping = false
}
// Examples: messageId, response.body, approvalDecision, form.submission, slack.ts

Transient Output (not persisted)

Flows downstream but not worth storing in workflow memory.

DataFlowPolicy = new DataFlowPolicy
{
    AcceptsUpstreamInput     = false,
    EmitsToDownstream        = true,
    PersistsToMemory         = false,
    ExcludeFromInputMapping  = true,
    ExcludeFromOutputMapping = false
}
// Example: response.status

Data Flow Diagram

Upstream Node Output
        │
        ▼  (AcceptsUpstreamInput = true  AND  ExcludeFromInputMapping = false)
┌───────────────────────────────┐
│         Node Execution        │
│                               │
│  [INPUT FIELDS]               │  ← static config + expression eval + upstream mapping
│  [OUTPUT FIELDS]              │  ← set by executor after running
└───────────────────────────────┘
        │
        ├── Downstream nodes   (EmitsToDownstream = true  AND  ExcludeFromOutputMapping = false)
        │
        └── Workflow Memory    (PersistsToMemory = true)