Stand-alone Flow

Prerequisite: Understand Data Flow concepts and Bridges.

Stand-alone flows provide raw Benthos access for custom data processing when bridges or stream processors aren't sufficient. They're the fallback mechanism for write flows, external integrations, and specialized transformations.

When to Use

Use stand-alone flows for:

• Point-to-point data transformation

• External system integration (databases, APIs, files)

• Custom processing that doesn't fit bridge patterns

Use bridges instead for:

• Industrial device connections

• Data that needs UNS organization

• Connections requiring health monitoring

UI Capabilities

Creating a Stand-alone Flow (UI)

Step 1: Navigate to Data Flows

Go to Data Flows → Standalone tab and click Add Standalone Flow:

Step 2: Configure the Flow

The configuration interface has multiple sections:

Key sections:

• General: Name, instance, and state control (Active/Stopped)

• Input (YAML): Configure data source (see Benthos-UMH inputs)

• Processing (YAML): Transform data with processors

• Output (YAML): Send to any destination (generic, not auto-generated like bridges)

• Examples: Pre-built templates including database bridges

Step 3: Use Example Templates

Click the Examples tab to access pre-built configurations:

Available examples include:

• mqtt_to_kafka_historian_bridge: MQTT to Kafka with historian pattern

• kafka_to_postgresql_historian_bridge: Write to TimescaleDB (like Classic)

• opcua_to_umh_core: OPC UA integration

• generate_to_stdout: Testing pattern

Step 4: Control Flow State

Use the state dropdown to control execution:

• Active: Flow is running

• Stopped: Temporarily disabled (useful for maintenance)

Managing Stand-alone Flows

Right-click any flow for quick actions:

Options include:

• Standalone Flow: Edit configuration

• Logs: View real-time logs

• Metrics: Monitor performance

• Delete: Remove the flow

Configuration (YAML)

Stand-alone flows use standard Benthos configuration:

dataFlow:
  - name: custom-processor
    desiredState: active
    dataFlowComponentConfig:
      benthos:
        input:
          # Any Benthos input
        pipeline:
          processors:
            # Processing logic
        output:
          # Any Benthos output

Migrating from Benthos

Existing Benthos configurations work with minimal changes:

# Original Benthos config
input:
  mqtt:
    urls: ["tcp://broker:1883"]
output:
  stdout: {}

# As UMH Core stand-alone flow
dataFlow:
  - name: migrated-flow
    desiredState: active
    dataFlowComponentConfig:
      benthos:
        input:
          mqtt:
            urls: ["tcp://broker:1883"]
        output:
          stdout: {}

Next Steps

• Learn about Bridges for device connectivity

• Explore Stream Processors for data transformation

• See Benthos-UMH Documentation for all processors