# \[ANNOUNCE\] @waldbaer/node-red-retry

**URL:** <https://discourse.nodered.org/t/announce-waldbaer-node-red-retry/90754>\
**Category:** Share Your Nodes\
**Created:** [6 September 2024 14:56 UTC](https://discourse.nodered.org/t/announce-waldbaer-node-red-retry/90754 "2024-09-06T14:56:12Z")\
**Posts on this page:** 9\
**Page:** 1

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**Author:** ![waldbaer](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/waldbaer/32/74212_2.png) [@waldbaer](https://discourse.nodered.org/u/waldbaer)\
**Post date:** [6 September 2024 14:56 UTC](https://discourse.nodered.org/t/announce-waldbaer-node-red-retry/90754/1 "2024-09-06T14:56:12Z")

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Hi,

I’m excited to announce the release of my new node, designed to simplify the implementation of retries within Node-RED flows.

### Motivation

I use Node-RED to manage my smart home, which involves interacting with various devices, bus systems, internet services, and more. Unfortunately, some of these devices or services occasionally fail to respond, return errors, or become unreachable.

Since many of these systems are essentially "black boxes" for me, I can’t always address the root causes. Instead, I want to build a system that is as robust as possible against these sporadic issues.

In many cases, simply **retrying** the request or query to the device or service solves the problem.

However, I couldn’t find an existing Node-RED node that simplifies implementing the necessary retry loops. The only resource I came across was the cookbook article, '[Automatically retry an action after an error](https://cookbook.nodered.org/basic/retry-on-error)', which provides some guidance on implementing a retry mechanism.

A key limitation of the pattern described in the article is that it can lead to an infinite loop if the error can’t be resolved through retries. Additionally, the pattern only works if the caught `msg` contents are not altered by the flow.

### Solution

After experimenting with a subflow template, I decided to develop a new node that simplifies creating retry flows and loops. This node essentially stores the last valid message and resends it if an error is reported. The retries are capped at a configurable maximum and can be optionally delayed (similar to the Delay node).

This is the new born node:

> **[@waldbaer/node-red-retry](https://flows.nodered.org/node/@waldbaer/node-red-retry)**
>
> Configurable retry mechanism for Node-RED flows.

### Future

There are several ideas for future improvements:

- Independent retry state per `msg.topic`
- More advanced retry strategies (e.g., `N` fast retries followed by `M` slower retries)
- Dynamic control through `msg` properties.
  - Set the retry strategy using `msg.strategy`
  - Set delay time using `msg.delay`

I hope this node will be useful to many other Node-RED enthusiasts.

I'm eager to receive constructive feedback!

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**Author:** ![marcus-j-davies](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/marcus-j-davies/32/103435_2.png) [@marcus-j-davies](https://discourse.nodered.org/u/marcus-j-davies)\
**Post date:** [6 September 2024 16:30 UTC](https://discourse.nodered.org/t/announce-waldbaer-node-red-retry/90754/2 "2024-09-06T16:30:45Z")

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Great use of the `catch` Node @waldbaer

One feature I would like to see, is a 2nd output pin, that is used to sink the final retry (upon failure), as the end user, can then route it later for investigation of the cause.

A node like this, will be a potent mix when used with my Semaphore+ Node

**node-red-semaphore-plus**  
(I won't link, in fear of hijacking your reveal)

Great work! 👍

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**Author:** ![waldbaer](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/waldbaer/32/74212_2.png) [@waldbaer](https://discourse.nodered.org/u/waldbaer)\
**Post date:** [6 September 2024 16:40 UTC](https://discourse.nodered.org/t/announce-waldbaer-node-red-retry/90754/3 "2024-09-06T16:40:49Z")

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@marcus-j-davies do you want to get the last retried `msg` on the second output or actually the last error `msg` which is _not_ triggering another retry?

For the second case the retry node is already re-throwing this last error message by itself in case the max. number of retries is already reached. As shown in the example another catch node for the retry node itself can be used to get this last error `msg` for possible post-mortem handling.

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**Author:** ![marcus-j-davies](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/marcus-j-davies/32/103435_2.png) [@marcus-j-davies](https://discourse.nodered.org/u/marcus-j-davies)\
**Post date:** [6 September 2024 16:59 UTC](https://discourse.nodered.org/t/announce-waldbaer-node-red-retry/90754/4 "2024-09-06T16:59:50Z")

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One (very minor) thing.

The link to `examples` is using relative paths in the readme - the markdown renderer in the flows website, will only (purposely) target the `master` repo and using `raw` when its NOT an `.md` extension.

It's a quirk I raised a while ago (and hence the need to target master/raw) , it's no biggy, but thought id mention it

 ![Screenshot 2024-09-06 at 18.01.42](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/9/7/9772a4148799b37d60554892d836eec607cb7ce1.png)

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<div class="post-metadata">

**Author:** ![marcus-j-davies](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/marcus-j-davies/32/103435_2.png) [@marcus-j-davies](https://discourse.nodered.org/u/marcus-j-davies)\
**Post date:** [6 September 2024 17:16 UTC](https://discourse.nodered.org/t/announce-waldbaer-node-red-retry/90754/5 "2024-09-06T17:16:37Z")

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> [@waldbaer](#):
>
> do you want to get the last retried `msg` on the second output or actually the last error `msg` which is _not_ triggering another retry?

What I mean is: If, on the final retry, it still fails, to pass it out to a 2nd Pin.

**Example** : I will want to store the error, if it failed 3 times for example (the 4th failure, to be reported out on pin 2)

A kind of

> I tried this darn thing 3 times, so I will instead send it to be looked at by an admin  
> (out on pin 2)

Im just thinking out aloud 😇

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**Author:** ![LosinIt](https://avatars.discourse-cdn.com/v4/letter/l/439d5e/32.png) [@LosinIt](https://discourse.nodered.org/u/LosinIt)\
**Post date:** [6 September 2024 18:31 UTC](https://discourse.nodered.org/t/announce-waldbaer-node-red-retry/90754/6 "2024-09-06T18:31:35Z")

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Could be quite handy. 👍

Isn't it convention here to put "contrib" in the names of these nodes?

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<div class="post-metadata">

**Author:** ![marcus-j-davies](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/marcus-j-davies/32/103435_2.png) [@marcus-j-davies](https://discourse.nodered.org/u/marcus-j-davies)\
**Post date:** [6 September 2024 18:41 UTC](https://discourse.nodered.org/t/announce-waldbaer-node-red-retry/90754/7 "2024-09-06T18:41:14Z")

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> [@LosinIt](#):
>
> Isn't it convention here to put "contrib" in the names of these nodes?

Not now.

The rulings have changed : as long as its scoped something like : `@dev-name/%`  
One is free to use anything they see fit:

But as a guide : `@dev/node-red-<magic>`

As long as it contains the `node-red` keyword (and is a Node RED Node) it will get indexed

This only applies to NEW nodes being introduced

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**Author:** ![Colin](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/colin/32/17040_2.png) [@Colin](https://discourse.nodered.org/u/Colin)\
**Post date:** [6 September 2024 21:14 UTC](https://discourse.nodered.org/t/announce-waldbaer-node-red-retry/90754/8 "2024-09-06T21:14:18Z")

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> [@waldbaer](#):
>
> However, I couldn’t find an existing Node-RED node that simplifies implementing the necessary retry loops

Did you see [node-red-guaranteed-delivery (node) - Node-RED](https://flows.nodered.org/node/@colinl/node-red-guaranteed-delivery)? I think it should be able to solve your problem.

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<div class="post-metadata">

**Author:** ![waldbaer](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/waldbaer/32/74212_2.png) [@waldbaer](https://discourse.nodered.org/u/waldbaer)\
**Post date:** [10 October 2024 18:33 UTC](https://discourse.nodered.org/t/announce-waldbaer-node-red-retry/90754/9 "2024-10-10T18:33:54Z")

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@marcus-j-davies  
I added support for second output port with the just released version **1.1.0**.

From the Help:

> If the max. number of retries is exceeded the _retry_ node forwards any subsequent error `msg` to the second output port. Optionally the error `msg` can be re-thrown as error by the _retry_ node if option 'Throw as Error If Retry Limit Is Exceeded' is enabled.