MQTT activity has uncaught empty result

[dcsouthwick]

Trying to publish messages with MQTT activity hangs after the first completion.

2020-01-28T16:54:20.010+0100	DEBUG	[flogo.activity.mqtt] -	Applying InputMapper
2020-01-28T16:54:20.010+0100	DEBUG	[flogo.activity.mqtt] -	Published Message: {"message":"Hello World"}
2020-01-28T16:54:20.010+0100	DEBUG	[flogo.activity.mqtt] -	Applying OutputMapper
2020-01-28T16:54:20.010+0100	DEBUG	[flogo.flow] -	Task 'mqtt_3' is done
2020-01-28T16:54:20.010+0100	DEBUG	[flogo.flow] -	Notifying flow that end task 'mqtt_3' is done
2020-01-28T16:54:20.010+0100	DEBUG	[flogo.flow] -	Checking if all tasks done or skipped
2020-01-28T16:54:20.010+0100	DEBUG	[flogo.flow] -	All tasks done or skipped
2020-01-28T16:54:20.010+0100	DEBUG	[flogo.flow] -	Flow Done
2020-01-28T16:54:20.010+0100	DEBUG	[flogo.flow] -	Done Executing flow instance [a008dc42525a066c4a0785dba93a6109] - Status: 500
2020-01-28T16:54:20.010+0100	INFO	[flogo.flow] -	Instance [a008dc42525a066c4a0785dba93a6109] Done
2020-01-28T16:54:20.010+0100	DEBUG	[flogo] -	Action-Worker-1: Received result: &runner.ActionResult{results:map[string]interface {}{}, err:error(nil)}
2020-01-28T16:54:20.010+0100	DEBUG	[flogo] -	Action-Worker-1: Completed Request
2020-01-28T16:54:20.010+0100	DEBUG	[flogo] -	Action 'github.com/project-flogo/flow' returned

Example Flow:

{
  "name": "Edge",
  "type": "flogo:app",
  "version": "0.0.1",
  "appModel": "1.1.0",
  "description": "Edge Metrics MQTT",
  "imports": [
    "github.com/project-flogo/contrib/activity/log",
    "github.com/project-flogo/edge-contrib/trigger/mqtt",
    "github.com/project-flogo/flow",
    "mqtt_1 github.com/project-flogo/edge-contrib/activity/mqtt"
  ],
  "triggers": [
    {
      "id": "receive_mqtt_message",
      "ref": "#mqtt",
      "name": "Receive MQTT Message",
      "description": "Simple MQTT Trigger",
      "settings": {
        "broker": "tcp://localhost:1883",
        "id": "mqtt_subscribe",
        "cleanSession": true
      },
      "handlers": [
        {
          "settings": {
            "topic": "test",
            "qos": 0
          },
          "action": {
            "ref": "#flow",
            "settings": {
              "flowURI": "res://flow:mqtt"
            },
            "input": {
              "message": "=$.message"
            }
          }
        }
      ]
    }
  ],
  "resources": [
    {
      "id": "flow:mqtt",
      "data": {
        "name": "MQTT",
        "description": "Reads MQTT device readings, and publishes to cloud VIA MQTT",
        "metadata": {
          "input": [
            {
              "name": "message",
              "type": "string"
            }
          ]
        },
        "tasks": [
          {
            "id": "log_2",
            "name": "Log",
            "description": "Logs a message",
            "activity": {
              "ref": "#log",
              "input": {
                "message": "=$flow.message",
                "addDetails": true
              }
            }
          },
          {
            "id": "mqtt_3",
            "name": "MQTT Activity",
            "description": "Send MQTT message",
            "activity": {
              "ref": "#mqtt_1",
              "input": {
                "message": "=$flow.message"
              },
              "settings": {
                "broker": "tcp://localhost:1883",
                "id": "flogo_publish",
                "qos": 0,
                "topic": "flogo",
                "retain": false,
                "cleanSession": true
              }
            }
          }
        ],
        "links": [
          {
            "from": "log_2",
            "to": "mqtt_3"
          }
        ]
      }
    }
  ]
}

[skothari-tibco]

How are you setting up your mqtt server ?

[dcsouthwick]

atm its a simple eclipse mosquitto server on localhost, no additional settings