Show HN: Visual flow-based programming for Erlang, inspired by Node-RED

by Towaway69 • 1 year ago

243 97 1 year ago

Hi There,

Erlang-RED has been my project for the last couple of months and I would love to get some feedback from the HN community.

The idea is to take advantage of Erlangs message passing and low overhead processes to have true concurrency in Node-RED flows. Plus also to bring low-code visual flow-based programming to Erlang.

tzarko• 1 year ago

This is neat - maybe move the example section higher up; it looks great and gives a much better idea of what the system looks like visually, which to me is key in node-based envs.

Towaway6923• 1 year ago

One example would be the website I've created using Erlang-RED[1]

But it's early days so I've yet come up with good examples.

I would really like to get some examples from the Erlang community and implement those, so if anyone has any ideas please contact me!

[1] https://red-erik.org

js4ever• 1 year ago

Congratulations for the launch! Also I never heard of that license before:

"LICENSE - DON'T DO EVIL" https://github.com/gorenje/erlang-red?tab=License-1-ov-file#...

Also I recommend you to put screenshots higher in the readme and also provide real world use case instead of fully abstract examples

Towaway6923• 1 year ago

Thanks for the suggestion, I’ll move the examples up and add a link to a running instance.

The license is a reminder that open source software isn’t free, in this case, I would like folks to think about what is evil. That’s the price tag.

The license isn’t enforceable and won’t be enforced.

tough• 1 year ago

Hopefully karma takes care of it heh

pvg2• 1 year ago

You should absolutely use whatever license you want but the actual price tag a nonstandard license adds is 'far fewer people will be able to try or contribute to your project'. Which might be totally ok for your purposes, just pointing it out since many people who dabble in 'license as messaging' for fun aren't aware of the impact/implications.

adastra223• 1 year ago

Licenses are enforceable and will prevent many people from collaborating with you, due to the burden of legal review.

90s_dev3• 1 year ago

About 15 years ago I made a custom MIT or BSD license that added:

"You agree to think carefully and always reflect about what you do and why you do it" or something to that effect. I thought I was so clever at the time.

90s_dev3• 1 year ago

Now I'm on the fence about adding philosophy to software licenses, even if only in a joking way. It can be fun and even thought provoking, but it could get in the way of genuine business adoption for basically no return (you never know if it helps influence anyone for the better, and most likely it doesn't).

pydry2• 1 year ago

It's a cool license in that it triggered Google enough to bar the use of jslint and led IBM's lawyers to seek out a special exemption to allow them and their customers to use JSON for evil.

No company's PR will ever tell you what the soul of a company is like but their lawyers will indirectly tell you everything.

adastra223• 1 year ago

That’s a ridiculous take. The fact is “evil” is so ill defined that it would have been an unlimited liability. That’s a reflection of the world, not IBM.

concerndc1tizen• 1 year ago

I've been interested in this for years.

Are there other similar projects that you're familiar with? Perhaps targeting other languages?

What are the major problems with this approach to programming? Are large programs hard to work with?

Towaway6923• 1 year ago

I know of Py-Red[1] which is an attempt to do the same but with Python. Using Node-RED as a frontend and something else as a backend, no I haven't heard of anything similar.

Main problems with visual flow based programming is the tooling: there aren't any good tools for doing visual comparison nor visual version control. Things like GitHub aren't able to render flow code as seen in the editor.

For Node-RED that means that the Json that defines a flow can be compared but that soon becomes meaningless because semantic changes get mixed with visual changes, i.e., that the x,y coordinates of a node have changed - is meaningless for the logic of the code.

This means that code sharing and collaborative development is difficult purely visually but only because tooling is missing. Compared to textual programming before things like SourceForge or Git and we had the same issues as we do with visual coding now.

Node-RED has a bunch of features to make large programs maintainable. Things like link nodes that allow jumping between flows also allow code reuse. There also subflows which encapsulate repeated code and can be referenced from anywhere.

That's also why I chose Node-RED for this because it seems to be the most mature and best maintained low-code visual flow-based programming tool. There are others such as n8n (which seems to be the other biggie) but they lack the generalness of Node-RED. I can create web sites with Node-RED while and the same time controlling my LEDs via Raspberry installation. Node-RED is extremely flexible.

[1] https://github.com/mdkrieg/py-red

regularfry• 1 year ago

Speaking of controlling LEDs, there's also https://www.atomvm.net/doc/main/index.html. From a very quick scan it looks like it would need some fiddling (especially around the filesystem) to get it to work, but being able to scale down to smaller devices than a full pi would be very, very interesting.

paddy_m4• 1 year ago

re:version control

How stable are node and edge IDs and their ordering? Could you sort the JSON before saving so the output is more stable and diff-able?

Another thought is, how would you code up a flow like this in your preferred language if you were just writing code in that language (you didn't care about the visual editting). Call most of the same functions, but do it directly. Ok, think about that, then write a transformation from the NODE language to output source in your preferred language.

I have some sense that coding this type of control flow logic doesn't work well with text line based diffs because of the complexity of the problem, less the syntax.

punnerud• 1 year ago

One star on Gighub, could still be good though. Any alternatives on Python that is equally used.

HomeAssistant build on Python have an Node-Red extension, would be nice to see a Python version with more seamless integration

applied_heat• 1 year ago

For function block programming used in control systems in PLCs there are tools like copia.io that are basically GitHub for version control and can do visual diff of the diagrams

jayd16• 1 year ago

Unreal Blueprint is probably the most popular. Its a custom system over a fairly customized C++ framework.

Visual scripting can be highly productive. The major issue is these visual scripts usually do not map cleanly back to text so you're throwing away decades of tooling. They usually don't merge well either.

paddy_m4• 1 year ago

This is related to visual programming, not flow based programming.

I modified a python hosted lisp interpreter to read JSON flavored lisp - JLISP. It's much easier to get a web frontend to output JSON then lisp. Then I made a simple Low Code UI built around this language. The editor has operations (invocations of lisp functions) organized left to right like a timeline in CAD software, then you can click on an individual operation to edit the arguments.

Here is a video walking through the system https://youtu.be/3Tf3lnuZcj8

Live edittable notebook (slow to load, runs python in WASM) https://marimo.io/p/@paddy-mullen/jlisp-in-buckaroo

I'll make a statically exported Jupyter notebook shortly

WillAdams• 1 year ago

Well, there are pages on problems such as;

https://scriptsofanotherdimension.tumblr.com/

https://blueprintsfromhell.tumblr.com/

and the biggest problem is that a strong bound is screen/display size --- any code chunk which won't fit on a single screen becomes hard to follow (which direction does one scroll next?) and if one does the obvious of declaring modules, then one runs into the wall of text which one was presumably trying to escape from --- just each word is wrapped up in pretty boxes and decorated with lines.

My take on this has always been that we don't have an answer for the question:

What does an algorithm look like?

That said, I work in this style when I can, often using:

https://www.blockscad3d.com/editor/

to rough out a design, or:

https://github.com/derkork/openscad-graph-editor

for more complex projects --- though that latter usually with a special-purpose library I've been working on: https://github.com/WillAdams/gcodepreview

randunel• 1 year ago

I see there's some suggestions here, you may want to give nodescript.dev a go, it's also nodejs based.

As a disclaimer, I'm somewhat affiliated with the project.

smartmic• 1 year ago

No Artificial Intelligence was harmed in the creation of this codebase. This codebase is old skool search engine (ddg), stackoverflow, blog posts and RTFM technology.

Good. To me, that also means that no human intelligence was degraded as a result. It sounds like a quality badge.

thinkyfish• 1 year ago

I was just thinking of making something like this last night but using FLENG instead of Erlang ;) I'm really glad more people are taking inspiration from Node-RED, I will definitely be playing with this!

Towaway6923• 1 year ago

FLENG[1] - Wow, "low level concurrent logic programming language descended from Prolog" - sounds like an easy swap out for Erlang since they have the same heritage. ;)

[1] http://www.call-with-current-continuation.org/fleng/fleng.ht...

arresin2• 1 year ago

Can someone recommend an Erlang course / book?

Towaway6923• 1 year ago

I keep running into learn you some erlang[1] which seems to be a good online resource. The author of which also wrote the "Erlang in Anger"[2] book.

Then there is the BEAM book[3] which provides an deep dive into Erlang and the BEAM virtual machine.

I'm not the best person to ask since I'm only starting out on Erlang! I much prefer to code visually :)

[1] https://learnyousomeerlang.com [2] https://www.heroku.com/blog/erlang-in-anger/ [3] https://blog.stenmans.org/theBeamBook/

arresin2• 1 year ago

Thanks for the suggestions! I looked at "learn you some erlang" and I like the style and humor of it.

randito• 1 year ago

You may want to consider Elixir instead. It has an easier syntax and is (don't quote me on this) equivalent in function and purpose with Erlang. Plus you get lots of other goodies like LiveView (notebooks) and a good web stack (Phoenix).

Towaway6923• 1 year ago

I prefer Erlang because it makes the uniqueness of its paradigm clear. Tail recursion, function matching and, bang, everything is a message!

Elixir makes everything seem like Ruby code and many of those Erlang concepts are hidden away, which is also ok but also takes much away.

My aim with ErlangRED is that both are supported, there is a repository for Elixir code[1] that is included in ErlangRED - so I don't take sides, rather I would like to take advantage of both paradigms.

[1] https://github.com/gorenje/erlang-red-elixir-helpers

paddy_m4• 1 year ago

Nice work! A couple of comments

1. You don't explain what flow based programming is or when it should be used. It looks like it represents some type of data pipeline, but I'm not sure.

2. Who is this repo for? PL enthusiasts, tool builders of type $X?

3. What are operators?

4. I understand that this is supposed to execute on an Erlang cluster/VM... Could you build a JS implementation of the functions so that you could build interactive demos in a browser? The lack of multithreading in JS doesn't rally matter, you just want to be able to send 10 line examples from one function to another.

5. A fun challenge for documenting projects like this, explain it as you would to a non-technical family member. It forces you to define the other things in erlang in a very direct and simple way.

6. Make a video explaining the project.

paddy_m4• 1 year ago

Ahh, you didn't create Node-RED editor. That's an external project. I didn't understand this at first, and probably explains a lot of my confusion

https://nodered.org/

Towaway6923• 1 year ago

No, that much talent I don't have :)

Node-RED has a create frontend that just works and the APIs to the server are clearly defined. So it's relatively easy to swap out the backend - that's what I did.

Erlang has many features that make flow based programming (as implemented by Node-RED) simpler - e.g., message passing builtin and cheap processes and cheap concurrency.

adastra223• 1 year ago

Why not just use Node-Red in that case?

Towaway6923• 1 year ago

NodeJS isn't truly concurrent, it is event-based single threaded - fast but not concurrent.

I use Node-RED every day! This is an exercise in applying the concept of flow based programming to another programming language. For me, flow based programming is like object oriented programming or functional programming or procedural ... etc. So the idea is to take the paradigm and apply to Erlang.

Clarification: I've been using everyday Node-RED for last three years and have built many things with it - including my mind map!

Towaway6923• 1 year ago

1. Ah sorry, indeed I forgot to add a link to J. Paul Morrison[1] the inventor of FBP - definitely add that.

2. The target audience is definitely Erlang developers who have not come across FBP before. But I didn't really ask myself that question since FBP is a hard sell at the best of times and selling Erlang with FBP is probably impossible! This is very niche ;)

3. Operators/Clients are hopefully those designing Erlang architectures. At the moment, that is really clear and it's something that has become clear for me in the last couple of months. When I started out, I was doing it as a finger exercise to see how far my Erlang skills would take me. Then I started creating test flows for testing node functionality - that turned into a testsuite[2] that can be used to test Node-RED functionality for correctness. At the moment, this is just a way of introducing the concepts of FBP to a new set of developers - Erlang developers.

4. I did actually create a in-browser-only Node-RED[3] which has some functionality and gives a feel of using Node-RED. There is also a live version of Erlang-RED[4] which is running on the BEAM.

5. Impossible :) To explain Node-RED and/or FBP to anyone outside of the IT - I keep using pipes and water hoses and sprinkles as metaphors!

6. I've made a couple of videos explaining my other visual coding idea[5] - didn't help ;) But yes, in the long term I definitely have to do something about the marketing because FBP does not sell itself...

[1] https://jpaulm.github.io/fbp/index.html

[2] https://github.com/gorenje/erlang-red-flow-testsuite

[3] https://cdn.flowhub.org/ (repo: https://github.com/gorenje/cdn.flowhub.org)

[4] https://ered.fly.dev/node-red

[5] https://flowhub.org

nisten• 1 year ago

the hivemind thinks alike

Arch-TK2• 1 year ago

I saw Node-RED recently, and now this. While I think these are cool (and I would rather Erlang than NodeJS), is there some code based system for these kinds of things?

I know I can just write code, but I mean a DSL or some library specifically oriented around solving exactly these kinds of event driven sequencing/action problems.

Towaway6923• 1 year ago

Not to my knowledge, the closest thing to a DSL for Node-RED is its flows.json format for storing flow configurations.

It's a very simple array-of-object format with the graph/flow definitions defined by node ids and wires. It is fairly simple to create a minimalist interpretor for that format.

Also NodeRED is a very stable piece of software that has been around for over ten years. Yet I can take a flows.json file from today and have it run on the first releases of Node-RED, i.e., the format is backward compatible yet easily extendable.

event driven sequencing/action problems.

Flow based programming[1] isn't strictly event driven, it's implemented that way in NodeJS because NodeJS does not have the concept of messages, only events.

Erlang has message passing between independent processes and therefore, IMHO, better suited to FBP.

[1] https://jpaulm.github.io/fbp/index.html

Arch-TK2• 1 year ago

Firstly, thanks for the link and information on more of the roots of this kind of programming, I couldn't find this when I looked.

Regarding NodeRED. I don't dispute that it's stable, but my experience actually running any nodejs based software is that it's all heavily designed for running out of a container and a massive PITA to maintain otherwise. I already have enough hassle running zigbee2mqtt on my FreeBSD home server which wouldn't work in a linux jail because I couldn't figure out how to expose the zigbee dongle to it.

Secondly, the reason I wanted to run one of these was not because I wanted to use it to automate my house, but instead because I wanted to understand how it works so I could replicate it in my own weird way.

NortySpock• 1 year ago

I suggest one of Benthos' descendants, either Bento or RedPanda Connect.

Configuration driven, with a transformation DSL, and good documentation (I prefer the Bento documentation over RedPanda Connect's documentation). And Benthos explicitly refused to ack a consumed message upstream unless it had been acknowledged downstream, so it wouldn't drop messages on the floor unless you explicitly told it to.

a-ungurianu• 1 year ago

Wouldn’t all the ReativeX libraries (e.g. RxJS) count?

Is there any specific features you’d be looking for?

mogili• 1 year ago

There's also flogo https://github.com/TIBCOSoftware/flogo

pjmlp• 1 year ago

I am a big fan of visual programming, and also think visual and digital circuit design tools overlap quite nicely with functional programming languages.

The mess most people complain about in visual languages, also happens on text ones, the biggest difference is that visual ones make it quite clear the code lacks modularity.

Get to package stuff into reusable ICs more often.

All the best for the project.

Towaway6923• 1 year ago

visual ones make it quite clear the code lacks modularity.

NodeRED has the concept of subflows to encapsulate reusable code. There are a number of features that NodeRED has that make it more usable for long term projects but it's a steep learning curve.

I've been using Node-RED everyday for the last three years to find the edge, something that cannot be done but there has always been a visual solution. I'm starting to think Node-RED might be turing complete ;)

But I have to admit, I did build a lot of tooling around NodeRED to make that happen - visual flow comparison[1] was something that was missing, introspection of message flow[2] and visual code management[3] - all these things I need to maintain an overview of what I am doing.

[1] https://flows.nodered.org/node/@gregoriusrippenstein/node-re... [2] https://flows.nodered.org/node/@gregoriusrippenstein/node-re... [3] https://flowhub.org/

All the best for the project.

Thank you!

tlodboy• 1 year ago

Visual programming helps automate flows in circuit design and I feel adoption would be higher as well since most circuit designers for some reason prefer GUI

mystraline• 1 year ago

I was an early adopter of NodeRed. Earlier, it worked exceptionally well.

Now? Not so much.

Well, that's not exactly true. Base NodeRed works as well as before. But the libraries of modules to interface with all sorts of websites, APIs, hardware, and other stuff is rotten to the core.

Most plugins/js modules either just don't work, or 'successfully fail'. The easier fail case is where the module can't be installed due to ancient (6mo or older JS, sigh) modules.

I abandoned NR because its basically a hyper-speed bitrot due to terrible library module versioning. And I didn't want to reinvent the wheel on every system I wanted to touch.

wslh• 1 year ago

I don't think this is easily to solve, in general. Similar orchestrators (e.g. n8n) have the same issues because there are a lot of components dependencies that change with time and there is no real cohesion between the core and all kind of plugins. Probably a future "contracts/manifests" linking orchestrators with components could help.

Towaway6923• 1 year ago

I wrote an article about this[1] and you are definitely right: a lot of packages are rotting away a bit however, because NodeRED does a lot to stay backward compatible, older packages still work. The oldest ones I'm actively using are five or more years old, i.e., haven't been touched nor updated - still work.

What I tried to say in the article is the same as you say: base NodeRED, the core works really well and has great features - no questions. And even if packages die, the core will still remain usable and that makes a difference.

Its a bit like saying Linux is a pile of broken bits because the ls command has been updated in ten years: Linux will always work and those commands that are based on the core will continue to work becausae the Linux kernel will largely remain backward compatible. Packages fail when they have external dependencies that change but code that is solely based on the core will continue to work.

[1] https://blog.openmindmap.org/blog/crunchy-numbers

01100011• 1 year ago

Not surprising. Whenever you have a project like NR or HA you have a ton of barely working glue code written by people who just want to get it working and move on without any sort of commitment to maintenance. It allows these projects to rapidly expand their support but then that support quickly rots unless the core team assumes responsibility for maintenance. I really want to mess with home automation again but this sort of low software quality and resulting instability and maintenance hassles makes it not worth the effort.

anonzzzies• 1 year ago

I think it's a fundamental flaw for such project that will never get out of the niche regions and will only have a few fanatic users and collaborators to use the JS/npm ecosystem which is known, as you say, for having breaking changes every release of every module and modules having updates every day because of grifting for stars/relevance/whatever on github/npm. I would like to see this based on something that's stable for very long times because module devs are not being bothered by the github issues 'is this project dead? there have been no updates for 7 hours?!?!?!? whats going on', with people responding with alternatives as happens every day with at least 1 js module. Scheme, Lisp, Perl, a Prolog etc maybe.

oersted• 1 year ago

Node-RED is a amazing[*] tool for creating flows that describe concurrent processing, it is just a shame the NodeJS is single threaded. So why not use something that is multi-process from the ground up?

That's great! But now that we are doing this, it kind of makes me wish that it was not multi-processing and Erlang, but a more mainstream language with a better library ecosystem and focused on multi-threading instead, Rust comes to mind but there could be a better one.

Is there a visual flow programming language based on Rust that is relatively mature?

bheadmaster• 1 year ago

it kind of makes me wish that it was not multi-processing and Erlang, but a more mainstream language with a better library ecosystem and focused on multi-threading instead, Rust comes to mind but there could be a better one

Go sounds like a good candidate.

Intermernet• 1 year ago

There are 3 or 4 Go FBP packages. It seems to be completely capable, but FBP itself doesn't seem to have reached enough critical mass for them to be popular.

https://github.com/flowbase/flowbase is one, and it has links to to some others.

Towaway6923• 1 year ago

wish that it was not multi-processing and Erlang

Hehe - honestly I chose Erlang because I love the syntax and secondly because it is so niche. Flow based programming is niche, visual FBP is nicher, Node-RED is even nicher and Erlang is niche - it's niche all the way down ;)

Have a look at Elixir which is Erlang with Ruby syntax and also has a large community.

Also the intention is to be using the flow editor and not the lanuage underneath, so the end user won't even know that it's Erlang or NodeJS - I aim t stay compatible with Node-RED so that flows are actually interchangeable.

So to an certain extent it doesn't matter which language is used.

I did chose Erlang also because it is well suited to flow based programming being message based and flow based programming is all about passing immutable objects amongst independent processes .... that's Erlang in a nutshell.

notpushkin2• 1 year ago

Note that this uses (I hope!) Erlang processes, which are not to be confused with OS processes.

Towaway6923• 1 year ago

Yes Erlang processes all the way down!

macintux• 1 year ago

Yep. I researched JVM and .NET thread sizes once, to compare/contrast with Erlang processes, and the difference is ludicrous.

Erlang: ~1k

64-bit .NET thread: 4MB

fnord773• 1 year ago

seems like a jvm-based one would also fit that requirement. None that I can find

rdtsc4• 1 year ago

makes me wish that it was not multi-processing and Erlang, but a more mainstream language with a better library ecosystem and focused on multi-threading instead, Rust comes to mind but there could be a better one.

I am not quite following, why would we drop multi-processing with isolated tiny heaps with a few KBs each and move to multi-threading with a large multi-megabyte stacks per thread and all sharing and writing to the same heap? It seems like a step backward.

Rust comes to mind but there could be a better one.

I can see the excitement, but at the same time this is becoming a meme. I mean the drive-by comments of "why don't your rewrite it in Rust" on every repo or "show HN" post. It's kind of like nodejs from years past: "why don't your write in nodejs, it's webscale!". The problem is, after a while it starts to have an inverse dose response: it makes people run away from Rust just based on that kind of stuff.

SigmundA8• 1 year ago

I am not quite following, why would we drop multi-processing with isolated tiny heaps with a few KBs each and move to multi-threading with a large multi-megabyte stacks per thread and all sharing and writing to the same heap? It seems like a step backward.

Performance typically, hard to work in parallel on large amount of data performantly without multiple thread sharing a heap and you typically don't need large amount of threads because you don't actually have that many real cores to run them on.

Lots of little share nothing process are great conceptually but that does create significant overhead.

creata• 1 year ago

a better library ecosystem

For what it's worth, Erlang's standard library is decently "batteries-included". The C interop also isn't terrible.[1]

[0] https://www.erlang.org/doc/apps/stdlib/api-reference.html

[1] https://www.erlang.org/doc/system/tutorial.html

fnord773• 1 year ago

for a visual environment, I was expecting more images to show me what this tool is

Towaway6923• 1 year ago

There is a live demo[1] if you want to try it out!

For me, the focus is more on the Erlang part than the visual part since that's basically NodeRED.

[1] https://ered.fly.dev/node-red

fnord773• 1 year ago

thank you, very neat

aantix• 1 year ago

I would move your sample images to the top of the README.

Don't bury the lede.

nilslindemann2• 1 year ago

The thing which makes me be annoyed with Yours and the Node-RED site, is that you people do not define terms, before using them. Like "flow". What is this? A program?

Please maintain a glossary.

nilslindemann2• 1 year ago

Okay, It seems you do, https://flowfuse.com/node-red/terminology/, https://nodered.org/docs/user-guide/concepts, so please link to it.

Show HN: Visual flow-based programming for Erlang, inspired by Node-RED

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