MarbleSoft.FlowModule.MQTTLogger 1.5.0

MarbleSoft.FlowModule.MQTTLogger

MQTTLogger publishes log messages over MQTT and enriches flow messages with logging context. The only required field is message. All other fields are optional and are filled by the module when missing. The module also supports an items field to carry key/value-style metadata into the log output.

How It Works

1. Receives a message from the flow with a log entry at the configured source property (default: data)
2. Extracts level from the message payload or uses the configured default (default: Info)
3. Enriches optional metadata when missing:

• timestamp as UTC ISO 8601 with milliseconds
• traceId from trace context in message (data.headers.traces.flowChain, header.trace, trace)
• flowId and flow (flow name) from runtime/environment fallback
• module fallback to current module name

4. Stores in flow message at the configured target property (default: data.logging)
5. Publishes to MQTT using the configured topic and settings

Example Input

{
  "data": {
    "message": "Pack successfully created"
  }
}

Example Output (Flow Message)

{
  "data": {
    "message": "Pack successfully created"
  },
  "data.logging": {
    "timestamp": "2026-07-21T18:42:15.384Z",
    "level": "Information",
    "event": "PackCreated",
    "module": "TraceFinalizer",
    "flow": "PackCreation",
    "flowId": "f47ac10b-58cc-4372-a567-0e02b2c3d479",
    "machineId": "Machine-07",
    "traceId": "abc-123",
    "message": "Pack successfully created",
    "success": true,
    "items": [
      { "key": "orderId", "value": "A-1001" },
      { "key": "count", "value": 2 }
    ]
  }
}

MQTT Publication Example

When MQTT is enabled, the module publishes:

Topic: logging (default topic, configurable)

Message:

{
  "timestamp": "2026-07-21T18:42:15.384Z",
  "level": "Information",
  "flow": "PackCreation",
  "flowId": "f47ac10b-58cc-4372-a567-0e02b2c3d479",
  "traceId": "abc-123",
  "message": "Pack successfully created"
}

Configuration

• Source (default: data): Property path to read the log entry from
• Target (default: data.logging): Property path to write the enriched log context to
• DefaultLogLevel (default: Info): Log level when not specified in the message (level or logLevel)
• Topic (default: logging): MQTT topic to publish to
• Enabled: Set to true to enable MQTT publishing; when false, logs are only added to the flow message

Log Levels

Valid log levels (case-insensitive):

• Debug
• Info
• Warning
• Error
• Critical

Settings

1. Source

• Type: string
• Required: yes
• Validation: min length 1, max length 256
• Default: data
• Purpose: path used to read an existing log context

2. Target

• Type: string
• Required: yes
• Validation: min length 1, max length 256
• Default: data.logging
• Purpose: path used to write the log context

3. Default Log Level

• Type: string
• Required: no
• Default: Info
• Purpose: default level used when no LogLevel field is present in the message payload

4. MQTT publish settings (optional)

• Enable MQTT Publish: bool, default true
• MQTT Source Property: string path, default data, if empty the payload from Source is used
• MQTT Topic: string, required when MQTT is enabled, default logging
• MQTT Brokers: comma or line separated host:port list, default localhost:1883
• MQTT Protocol Version: enum V311 or V500
• Use TLS: bool, default true
• SSL Protocol: enum None, Tls12, Tls13
• Allow Untrusted Certificates: bool
• ClientId: optional string, generated automatically when empty
• CA Certificate: optional Crosser Certificate credential selector
• Client Certificate: optional Crosser Certificate credential selector
• MQTT User Credential: optional Crosser UsernamePassword credential selector
• QoS: AtMostOnce, AtLeastOnce, ExactlyOnce
• Retain: bool

Runtime behavior

• Reads payload from Source.
• Uses payload field message (or msg) as required message content.
• Sets timestamp to UTC ISO 8601 with milliseconds when missing.
• Sets level from payload (level/logLevel) or DefaultLogLevel.
• Resolves traceId from the trace context when not present in payload.
• Resolves flowId and flow from runtime/environment when not present in payload.
• Uses payload module when present; otherwise current module name.
• Writes the enriched context to Target and publishes to MQTT when enabled.