Weird queue output (empty message)

General
1

Got a weird error which I tracked down to queue node. Not sure what is going on.

NR version: 4.1.1.
Node: 22

When sending flush control message, it also outputs the control message from the queue (with flush prop removed).

The message I define with flush includes _msgid and _event properties. But I didn't set this in the function node it originated from. I used this function node to return flush message back to queue: return { flush: 1 };.

2

Digged some more, and it seems to be affected by link in/out nodes. When function node use return {reset: 1}, it automagically adds _msgid prop. When it goes through link node, _event prop is added.

Seems like queue node can handle msg with reset, _msgid and _event. But when I try the same with flush, _msgid and _event, it treats it as both a flush control message and a new message. This removes the flush prop, but keeps _msgid and _event. Here is a simplified example:

bilde
bilde1202×200 19.1 KB

[
    {
        "id": "afd7119ab90da785",
        "type": "inject",
        "z": "a7674a4aaf8a3c64",
        "name": "",
        "props": [],
        "repeat": "",
        "crontab": "",
        "once": false,
        "onceDelay": 0.1,
        "topic": "",
        "x": 1390,
        "y": 980,
        "wires": [
            [
                "bd046bd14e8ad79a"
            ]
        ]
    },
    {
        "id": "bd046bd14e8ad79a",
        "type": "function",
        "z": "a7674a4aaf8a3c64",
        "name": "flush",
        "func": "// reset any leftover in previous queue\nreturn { flush: 1 };",
        "outputs": 1,
        "timeout": "",
        "noerr": 0,
        "initialize": "",
        "finalize": "",
        "libs": [],
        "x": 1510,
        "y": 980,
        "wires": [
            [
                "1a5fb9a9de620724",
                "9ae07de9afcd7ef9"
            ]
        ]
    },
    {
        "id": "afa13d8bc425b20b",
        "type": "link in",
        "z": "a7674a4aaf8a3c64",
        "name": "link in 10",
        "links": [
            "1a5fb9a9de620724"
        ],
        "x": 1855,
        "y": 980,
        "wires": [
            [
                "7cd67bbf79c1dcad",
                "59bf2547ebe2d557"
            ]
        ]
    },
    {
        "id": "1a5fb9a9de620724",
        "type": "link out",
        "z": "a7674a4aaf8a3c64",
        "name": "link out 6",
        "mode": "link",
        "links": [
            "afa13d8bc425b20b"
        ],
        "x": 1615,
        "y": 980,
        "wires": []
    },
    {
        "id": "9ae07de9afcd7ef9",
        "type": "debug",
        "z": "a7674a4aaf8a3c64",
        "name": "debug 1: _msgid added",
        "active": true,
        "tosidebar": true,
        "console": false,
        "tostatus": false,
        "complete": "true",
        "targetType": "full",
        "statusVal": "",
        "statusType": "auto",
        "x": 1710,
        "y": 1020,
        "wires": []
    },
    {
        "id": "7cd67bbf79c1dcad",
        "type": "delay",
        "z": "a7674a4aaf8a3c64",
        "name": "queue",
        "pauseType": "rate",
        "timeout": "5",
        "timeoutUnits": "seconds",
        "rate": "1",
        "nbRateUnits": "60",
        "rateUnits": "minute",
        "randomFirst": "1",
        "randomLast": "5",
        "randomUnits": "seconds",
        "drop": false,
        "allowrate": false,
        "outputs": 1,
        "x": 2110,
        "y": 980,
        "wires": [
            [
                "8ddc534d989cc697"
            ]
        ]
    },
    {
        "id": "59bf2547ebe2d557",
        "type": "debug",
        "z": "a7674a4aaf8a3c64",
        "name": "debug 2: _evemt added",
        "active": true,
        "tosidebar": true,
        "console": false,
        "tostatus": false,
        "complete": "true",
        "targetType": "full",
        "statusVal": "",
        "statusType": "auto",
        "x": 2030,
        "y": 1020,
        "wires": []
    },
    {
        "id": "91a80240032f6b46",
        "type": "inject",
        "z": "a7674a4aaf8a3c64",
        "name": "",
        "props": [],
        "repeat": "",
        "crontab": "",
        "once": false,
        "onceDelay": 0.1,
        "topic": "",
        "x": 1390,
        "y": 1080,
        "wires": [
            [
                "1729cb0bc398109f"
            ]
        ]
    },
    {
        "id": "1729cb0bc398109f",
        "type": "function",
        "z": "a7674a4aaf8a3c64",
        "name": "flush",
        "func": "// reset any leftover in previous queue\nreturn { flush: 1 };",
        "outputs": 1,
        "timeout": "",
        "noerr": 0,
        "initialize": "",
        "finalize": "",
        "libs": [],
        "x": 1510,
        "y": 1080,
        "wires": [
            [
                "ecbc8660ad045e8a",
                "97934838227f3705"
            ]
        ]
    },
    {
        "id": "ecbc8660ad045e8a",
        "type": "debug",
        "z": "a7674a4aaf8a3c64",
        "name": "debug 1: _msgid added",
        "active": true,
        "tosidebar": true,
        "console": false,
        "tostatus": false,
        "complete": "true",
        "targetType": "full",
        "statusVal": "",
        "statusType": "auto",
        "x": 1710,
        "y": 1120,
        "wires": []
    },
    {
        "id": "97934838227f3705",
        "type": "delay",
        "z": "a7674a4aaf8a3c64",
        "name": "queue",
        "pauseType": "rate",
        "timeout": "5",
        "timeoutUnits": "seconds",
        "rate": "1",
        "nbRateUnits": "60",
        "rateUnits": "minute",
        "randomFirst": "1",
        "randomLast": "5",
        "randomUnits": "seconds",
        "drop": false,
        "allowrate": false,
        "outputs": 1,
        "x": 2110,
        "y": 1080,
        "wires": [
            [
                "65c1572afd9a258f"
            ]
        ]
    },
    {
        "id": "65c1572afd9a258f",
        "type": "debug",
        "z": "a7674a4aaf8a3c64",
        "name": "queue output: none",
        "active": true,
        "tosidebar": true,
        "console": false,
        "tostatus": false,
        "complete": "true",
        "targetType": "full",
        "statusVal": "",
        "statusType": "auto",
        "x": 2270,
        "y": 1080,
        "wires": []
    },
    {
        "id": "8ddc534d989cc697",
        "type": "debug",
        "z": "a7674a4aaf8a3c64",
        "name": "queue output: ghost message",
        "active": true,
        "tosidebar": true,
        "console": false,
        "tostatus": false,
        "complete": "true",
        "targetType": "full",
        "statusVal": "",
        "statusType": "auto",
        "x": 2310,
        "y": 980,
        "wires": []
    }
]

Seems like queue node has a bug that treats control messages with _event prop as both control message and a new message for the queue?

Temp fix for me is to always add function node before queue node with this code:

const isControlMessage = msg.flush != null || msg.reset != null;
const hasEvent = msg._event != null;
if (isControlMessage && hasEvent) {
  delete msg._event;
}
return msg;