# Error detecting really not "working"

**URL:** <https://discourse.nodered.org/t/error-detecting-really-not-working/15994>\
**Category:** General\
**Created:** [27 September 2019 11:37 UTC](https://discourse.nodered.org/t/error-detecting-really-not-working/15994 "2019-09-27T11:37:37Z")\
**Posts on this page:** 9\
**Page:** 1

<div class="post-metadata">

**Author:** ![Trying\_to\_learn](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/trying_to_learn/32/28400_2.png) [@Trying\_to\_learn](https://discourse.nodered.org/u/Trying_to_learn)\
**Post date:** [27 September 2019 11:37 UTC](https://discourse.nodered.org/t/error-detecting-really-not-working/15994/1 "2019-09-27T11:37:37Z")

</div>

Sorry folks, but I really am stuck with what is going on with error trapping.

To the best of my knowledge things are _ok_ as they were.  
Me, every wanting to stir the hornet's nest, I am trying to make the flow better.

This is what I have found to be the part which is the problem:

Code below:

![Screenshot%20from%202019-09-27%2021-03-29](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/2X/1/182f4b270b0452f4e9806e184768aad32f6d0f03.png)

As is/was the red line was there.  
All errors caught and passed to the next node.  
"Name flow" names the flow.  
The `gate` though shown as open should be closed.  
That goes up to the other node (circled in red) and there is where the fun happens.

The _idea_ is that usually it goes on through the gate and the `set topic` node basically does a bit more than the `name flow` node and passes on to the higher system.  
But sometimes when I am working on a flow, I don't want to propagate these errors and just keep them local.

So the `gate` is closed. However, that other `function` node just enables a local indication of a flow error rather than passing it up higher.

Anyway, so I was doing house keeping.  
Originally I messed up and forgot to move the `msg.error` to `msg.payload`.  
So down the stream the message was in `msg.error`, though I thought it was `msg.payload`.  
(But again: anyway.)

I optimised it and set `msg.payload = msg.error;`  
Then `delted msg.error;` to keep things succinct.

This is the code for the two `function` nodes:

```auto
[{"id":"169525cc.6f8a0a","type":"function","z":"c3ec93b2.f3154","name":"Name flow","func":"const flow_name_ = flow.get(\"name\");\nmsg.topic = flow_name;\nmsg.payload = msg.error;\ndelete msg.error;\nreturn msg;\n","outputs":1,"noerr":0,"x":4400,"y":300,"wires":[["3a30b545.b56caa","9b7d5e17.fff498"]]},{"id":"9b7d5e17.fff498","type":"function","z":"c3ec93b2.f3154","name":"","func":"var name = flow.get('name');\nvar ok = global.get('Error_Flow_Pass');\nvar stop = global.get('Error_Flow_Stop');\nvar caught = global.get('Error_Detected');\nvar counter = context.get('counter')|| 0;\n\n//node.warn(\"Name of the flow \" + name);\n// -- check if this is a CONTROL message.\nif (msg.topic == 'CONTROL')\n{\n node.warn(\"Control signal received \" + msg.payload);\n if (msg.payload == 'STOP')\n {\n context.set('notify',1);\n msg.topic = name;\n msg.colour = stop;\n } else\n {\n context.set('notify',0);\n msg.topic = name;\n msg.colour = ok;\n context.set('counter',0);\n node.status({});\n }\n return msg;\n}\n\n// -- Send YELLOW as the message if error detected.\n//\tThis is only if the error reporting is blocked.\nvar pass = context.get('notify') ||0;\nif (pass == 1)\n{\n if (counter == 1)\n {\n // set msg.payload to indicate\n node.status({fill:\"red\",shape:\"dot\",text:\"ERROR\"});\n node.warn(\"Error detected check indication\");\n msg.topic = name;\n msg.colour = caught;\n context.set('counter',2);\n }\nreturn msg;\n}\n","outputs":1,"noerr":0,"x":4590,"y":230,"wires":[["65452684.31ed48"]]}]

```

Originally it was more like:  
(from another machine and flow)

```auto
[{"id":"928681dd.e0c018","type":"function","z":"b4454b36.0344c","name":"Name flow","func":"var device_name = global.get('myDeviceName');\nmsg.topic =\"ERROR_REPORT/\" + device_name + \"/\" + flow.get(\"name\");\nnode.status({fill:\"red\",shape:\"dot\",text:\"ERROR\"});\nreturn msg;\n","outputs":1,"noerr":0,"x":4350,"y":220,"wires":[["3f278612.cb40ca","3f894e5e.00c832"]]},{"id":"3f894e5e.00c832","type":"function","z":"b4454b36.0344c","name":"","func":"var name = flow.get('name');\nvar ok = global.get('Error_Flow_Pass');\nvar stop = global.get('Error_Flow_Stop');\nvar caught = global.get('Error_Detected');\n\n//node.warn(\"Name of the flow \" + name);\n// -- check if this is a CONTROL message.\nif (msg.topic == 'CONTROL')\n{\n //node.warn(\"Control signal received \" + msg.payload);\n if (msg.payload == 'STOP')\n {\n context.set('notify',1);\n msg.topic = name;\n msg.colour = stop;\n } else\n {\n context.set('notify',0);\n msg.topic = name;\n msg.colour = ok;\n }\n return msg;\n}\n\n// -- Send YELLOW as the message if error detected.\n//\tThis is only if the error reporting is blocked.\nvar pass = context.get('notify') ||0;\nif (pass == 1)\n{\n // set msg.payload to indicate\n node.warn(\"Error detected check indication\");\n msg.topic = name;\n msg.colour = caught;\nreturn msg;\n}\n","outputs":1,"noerr":0,"x":4530,"y":170,"wires":[["aff43e4d.57c668"]]}]

```

So, I changed the code from the second one to the first one.

And when I tested it (by generating an error) it all went pear shaped.

I am 99.9% sure that it is the second node, because I have cut it down to basically those two nodes - with the `catch` node.

I inject an error and yuck.

Though not exactly the same node layout, this is my test bed.  
I have a `delay` node to attempt to `rate limit` the messages.  
Note I have disconnected the `link` node and I have a `debug` node looking at what is sent.

The `gate` is closed so that part of the flow isn't in the problem - yet.

So I press the `generate error` button (bottom) and this is what happens.  
(this is the code in that node:

```auto
var n = 23 + 56 / a;
//var n = 23 + 56 ;
msg.payload = n;
return msg;

```

)

 ![Screenshot%20from%202019-09-27%2021-21-31](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/2X/b/ba3b843efeff788590a39015009484fc09c9da90.png)

NOTE The _note_.  
If this is **not** there, I can press the button and I get an error.  
I then press the `NEXT` button and I see the error in the `debug` node.

I put in the link as indicated by the `note`, DEPLOY and press the `inject error` button.  
The machine dies.  
Looking at the CLI/terminal from which I started NR (in safe mode) I see this:

```auto
27 Sep 21:02:12 - [warn] [function:Variable repeat time] Value set
27 Sep 21:02:18 - [warn] [vcgencmd:Other stuff] Previous vcgencmd command hasn't finished yet
27 Sep 21:17:41 - [warn] [function:f445a2f0.bdbfb8] Control signal received STOP
27 Sep 21:20:09 - [warn] [function:Button Colour] Node Configuration not set
27 Sep 21:20:12 - [info] Stopping modified nodes
27 Sep 21:20:12 - [info] Stopped modified nodes
27 Sep 21:20:12 - [info] Starting modified nodes
27 Sep 21:20:14 - [info] Started modified nodes

```

Alas not much to tell me what is going on.

But a remote machine which is monitoring the machine in question basically tells me NR is dead.

SSH'ing to the machine on a second terminal I get this:

```auto
pi@TimePi:~ $ ./node-red_status.sh 
● nodered.service - Node-RED graphical event wiring tool
   Loaded: loaded (/lib/systemd/system/nodered.service; enabled; vendor preset: enabled)
   Active: failed (Result: timeout) since Fri 2019-09-27 20:15:34 AEST; 1h 17min ago
     Docs: http://nodered.org/docs/hardware/raspberrypi.html
  Process: 250 ExecStart=/usr/bin/env node-red-pi $NODE_OPTIONS $NODE_RED_OPTIONS (code=killed, signal=KILL)
 Main PID: 250 (code=killed, signal=KILL)

Sep 27 20:14:04 TimePi systemd[1]: Stopping Node-RED graphical event wiring tool...
Sep 27 20:14:56 TimePi Node-RED[250]: 27 Sep 20:14:56 - [warn] [catch:40abdd07.f5fb44] Message exceeded maximum number of catc
Sep 27 20:14:56 TimePi Node-RED[250]: 27 Sep 20:14:56 - [error] [catch:40abdd07.f5fb44] RangeError: Maximum call stack size ex
Sep 27 20:14:57 TimePi Node-RED[250]: 27 Sep 20:14:57 - [warn] [function:Button Colour] Node Configuration not set
Sep 27 20:15:34 TimePi systemd[1]: nodered.service: State 'stop-sigterm' timed out. Killing.
Sep 27 20:15:34 TimePi systemd[1]: nodered.service: Killing process 250 (node-red) with signal SIGKILL.
Sep 27 20:15:34 TimePi systemd[1]: nodered.service: Main process exited, code=killed, status=9/KILL
Sep 27 20:15:34 TimePi systemd[1]: Stopped Node-RED graphical event wiring tool.
Sep 27 20:15:34 TimePi systemd[1]: nodered.service: Unit entered failed state.
Sep 27 20:15:34 TimePi systemd[1]: nodered.service: Failed with result 'timeout'.
lines 1-17/17 (END)

```

So given it is _dead_.

Pressing `^c` in the CLI which started NR in safe mode does nothing.

I stop NR from the other CLI yields no result.

I think this was brought about by me _moving_ `msg.error` to `msg.payload` but I can't see anything which really points to that.

Yeah: My problem. But I am not seeing what is causing this.  
I've narrowed it down to those couple of nodes but can't see how it is doing it.

Thanks.

---

<div class="post-metadata">

**Author:** ![bakman2](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/bakman2/32/6207_2.png) [@bakman2](https://discourse.nodered.org/u/bakman2)\
**Post date:** [27 September 2019 11:49 UTC](https://discourse.nodered.org/t/error-detecting-really-not-working/15994/2 "2019-09-27T11:49:20Z")

</div>

first function node:

```auto
const flow_name_ = flow.get("name");
msg.topic = flow_name;

```

---

<div class="post-metadata">

**Author:** ![Trying\_to\_learn](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/trying_to_learn/32/28400_2.png) [@Trying\_to\_learn](https://discourse.nodered.org/u/Trying_to_learn)\
**Post date:** [27 September 2019 11:51 UTC](https://discourse.nodered.org/t/error-detecting-really-not-working/15994/3 "2019-09-27T11:51:34Z")

</div>

Yeah, and I shall admit I am not seeing anything wrong.

Oh. Ok the missing (or extra) \_

Thanks.

I'll look at it.

---

<div class="post-metadata">

**Author:** ![bakman2](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/bakman2/32/6207_2.png) [@bakman2](https://discourse.nodered.org/u/bakman2)\
**Post date:** [27 September 2019 11:52 UTC](https://discourse.nodered.org/t/error-detecting-really-not-working/15994/4 "2019-09-27T11:52:03Z")

</div>

Like this ?

> [@bakman2](#):
>
> flow\_name\_  
> flow\_name

---

<div class="post-metadata">

**Author:** ![Trying\_to\_learn](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/trying_to_learn/32/28400_2.png) [@Trying\_to\_learn](https://discourse.nodered.org/u/Trying_to_learn)\
**Post date:** [27 September 2019 11:53 UTC](https://discourse.nodered.org/t/error-detecting-really-not-working/15994/5 "2019-09-27T11:53:52Z")

</div>

Yeah, ok. So I stuffed up with the extra `_`.

But why am I not seeing any errors from that?

Particularly if I have a rate limit set so if it _runs away_ with errors compounding errors, it would at least slow them down and not grind the machine to 100% CPU load.

---

<div class="post-metadata">

**Author:** ![bakman2](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/bakman2/32/6207_2.png) [@bakman2](https://discourse.nodered.org/u/bakman2)\
**Post date:** [27 September 2019 12:07 UTC](https://discourse.nodered.org/t/error-detecting-really-not-working/15994/6 "2019-09-27T12:07:11Z")

</div>

> But why am I not seeing any errors from that?

To be honest, I have no idea what your flow is doing and/or what its' purpose is (it is not explained), I have some problems digesting this topic, I only noticed the typo. That is where problems usually start.

---

<div class="post-metadata">

**Author:** ![Trying\_to\_learn](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/trying_to_learn/32/28400_2.png) [@Trying\_to\_learn](https://discourse.nodered.org/u/Trying_to_learn)\
**Post date:** [27 September 2019 12:08 UTC](https://discourse.nodered.org/t/error-detecting-really-not-working/15994/7 "2019-09-27T12:08:57Z")

</div>

No worries.

I'm stupid.

Learning though. That's a good thing. I guess being awake for 18 hours isn't helping.

---

<div class="post-metadata">

**Author:** ![kuema](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/kuema/32/6542_2.png) [@kuema](https://discourse.nodered.org/u/kuema)\
**Post date:** [27 September 2019 16:20 UTC](https://discourse.nodered.org/t/error-detecting-really-not-working/15994/8 "2019-09-27T16:20:50Z")

</div>

I have read many of your posts... and many times you are claiming that you're stupid... but you are not! 🙂

You put a lot of effort into this, and as your name states are _trying to learn_, trying to understand things. You are doing exactly the right thing, you ask questions, engage in conversation and try to solve problems.

Failing and making mistakes is a part of the learning process.... so please, don't sell yourself short! 🕶

---

<div class="post-metadata">

**Author:** ![dceejay](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/dceejay/32/38_2.png) [@dceejay](https://discourse.nodered.org/u/dceejay)\
**Post date:** [27 September 2019 16:29 UTC](https://discourse.nodered.org/t/error-detecting-really-not-working/15994/9 "2019-09-27T16:29:09Z")

</div>

But please do get some sleep 💤 💤  
Your brain will be better for it.