References and Signals

Overview

Signals are static outputs exposed by blocks with lifecycles. Use signals in configuration expressions to create static dependencies between blocks.

Blocks with lifecycles

Blocks with lifecycles manage stateful resources (infrastructure, persistent services) that exist beyond individual event executions. These blocks:

• Create and manage external resources
• Expose signals for referencing static properties
• Have distinct lifecycle states
• Require user confirmation for creation and modification

Lifecycle States

State	Description
DRAFT	Block configured but resources not created
IN_PROGRESS	Resources being created or updated
READY	Resources live and signals available
FAILED	Resource creation or update failed
DRAINING	Resources being deleted

State Transitions

Creation Flow:

DRAFT → [user confirms] → IN_PROGRESS → READY

Update Flow (Sync):

READY → [config change] → IN_PROGRESS → READY

Deletion Flow:

READY → [user deletes] → DRAINING → [removed]

Signals

Signals are static properties exposed by blocks with lifecycles in READY state. Common signal types:

AWS S3 Bucket:

• arn - Bucket ARN
• name - Bucket name
• region - AWS region

SQS Queue:

• url - Queue URL
• arn - Queue ARN

API Gateway:

• url - Endpoint URL
• apiId - API identifier

signals Object

Syntax

signals.<camelCasedBlockName>.<signalName>

Parameters

Single parameter with format signals.<blockName>.<signalName>:

• blockName: Block name converted to camelCase (e.g., “My S3 Bucket” → myS3Bucket)
• signalName: Signal identifier exposed by the block

Usage Context

Examples

Basic Signal Reference:

// Block name: "Data Bucket", Signal: "arn"
signals.dataBucket.arn

Template String:

// Block name: "API Endpoint"
// Signal: "url"
`${signals.apiEndpoint.url}/users`

Multiple Signals:

{
  bucketArn: signals.dataBucket.arn,
  region: signals.dataBucket.region
}

ref() vs outputs

signals	outputs
References static signals	Accesses event data
Infrastructure properties	Dynamic per-event data
Doesn’t require event flow	Requires event connection

Configuration Dependencies

signals creates static configuration dependencies without requiring event flow connections:

The S3 Bucket block doesn’t need an event connection to the Create Object block. The ‘signals’ object establishes the configuration dependency.