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

Action	Available	Notes
Create flows	✅	Via UI with YAML editor
View flows	✅	Listed in Standalone tab
Edit configuration	✅	Direct YAML editing
Control state	✅	Active/Stopped toggle
Use example templates	✅	Pre-built samples available
Monitor status	✅	Throughput and state
View logs	✅	Real-time log streaming
View metrics	✅	Performance monitoring
Delete flows	✅	Via context menu

Creating a Stand-alone Flow (UI)

Step 1: Navigate to Data Flows

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

Standalone Flows List

Step 2: Configure the Flow

The configuration interface has multiple sections:

Standalone Flow Configuration

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:

Example Templates

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:

State Control

• Active: Flow is running

• Stopped: Temporarily disabled (useful for maintenance)

Managing Stand-alone Flows

Right-click any flow for quick actions:

Context Menu

Options include:

• Standalone Flow: Edit configuration

• Logs: View real-time logs

• Metrics: Monitor performance

• Delete: Remove the flow

Enable Debug Logging

For troubleshooting data processing issues in stand-alone flows, enable the debug_level configuration option:

Via YAML:

dataFlow:
  - name: custom-processor
    desiredState: active
    dataFlowComponentConfig:
      debug_level: true  # Enable detailed logging (default: false)
      benthos:
        # ...

What it controls:

• Log level: DEBUG (when true) vs INFO (when false, default)

• Detailed operational logging for input/output operations

• Processing step execution details

• Data transformation trace information

Important: Debug logging generates significantly more log data and may impact performance. Use only during active troubleshooting and disable afterward.

View logs via right-click → Logs. For comprehensive debug_level configuration reference, see Configuration Reference.

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