log component: log. Formats the message using JavaScript script and records it to a log file.

JavaScript script supports ECMAScript 5.1(+) syntax specification and some ES6 specifications, such as: async/await/Promise/let. It allows calling Go custom functions in the script, please refer to udf .

Configuration

Field	Type	Description	Default value
jsScript	string	js script	None

• jsScript: Formats the message. This field is the following function body content

      function ToString(msg, metadata, msgType) { 
          ${jsScript} 
       }
  

  • msg: Message content, if dataType=JSON, type is: jsonObject, you can use msg.temperature to operate. If dataType is other types, the field type is:string
  • metadata: Message metadata, type: jsonObject
  • msgType: Message type
  • Function return value type: string

TIP

Logger, can be configured by config.Logger , default output to console.

Relation Type

• Success: Execution successful, send the message to the Success chain
• Failure: Execution failed, send the message to the Failure chain

Execution result

This component will not change the content of msg.Data and msg.Metadata.

Configuration example

  {
    "id": "s1",
    "type": "log",
    "name": "Log",
    "configuration": {
      "jsScript": "return 'Incoming message:\\n' + JSON.stringify(msg) + '\\nIncoming metadata:\\n' + JSON.stringify(metadata);"
    }
  }

Application example

Example reference: Example (opens new window)