what about remote procedure calls?

[massimosala]

In the past two years I developed some projects on esp8266, esp32 any rpico. Sometimes I have to discard the esp8266 because there isn't sufficient memory to run certain algorithms and/or some basic functions are removed from its port. I know it is a tiny beast, but in the next years the same fate will occur for esp32 and other micros (our projects will grow, following the new hardware and customers requests). But it is a shame to waste hardware in this way. So I put up some routines on a web server and the micros call the server, it does the heavy lifting and returns the result to the micro. Ah, it isn't only a matter of micro constrains. Sometimes I prefer to have a RPC because 1) I haven't to re-code the same algorithms on different cpu (also other micros not running MP) and 2) I have a unique box (the server) where I can monitor the usage of the routines. The RPC available on the server are quite different, some examples: generate a uuid4, get/set values (flat database), hashing, Text To Speech. With the modern connectivity speeds they are quite usable also on WiFi. I just want to share my ideas: what do you think ? Have you any specific algorithm you think useful if callable as RPC ?

[Josverl]

gRPC is common today - but I'm not aware of any MicroPython implementation.

if you use websockets or ODATA / REST or plain HTTP,

You'll need a server - there are a few that can run on Big and Small python

1. MicroWebSrv2 - The last micro web server for IoTs (MicroPython) or large servers (CPython), that supports WebSocket, routes, template engine and with really optimized architecture (mem allocations, async I/Os).

then you may want to have a serialization protocol to send/recieve 'stuff' in limited memory

1. micropython-msgpack - MessagePack serialisation library optimised for MicroPython.
2. micropython-uprotobuf - A lightweight implementation of Google's Protocol Buffers (protobuf) for MicroPython.

there are a few other micropython RPC implementaions

• https://awesome-micropython.com/#rpc
• https://github.com/sistemicorp/p01-upyrpc

[andrewleech]

gRPC is common today - but I'm not aware of any MicroPython implementation.

gRPC is built on HTTP/2 which is not readily supported on micropython currently (I've searched). There have been efforts to make it run on other underlying services however none of the major platform / libraries look like they support this out of the box so you'd end up needing to custom build the other end of any gRPC based connection as well which kinda defeats the purpose in my mind.

I have thought of trying to port hyper/h2 pure python http/2 server to micropython to then build gRPC on top of it... but so far have just used mqtt instead.

[massimosala]

Hi @Josverl @andrewleech

My concept is different: a specialized web server, on internet, performing tasks - aka "remote procedure calls" - for the tiny micros.
I want to keep as minimal as possible the resources usage on the micros, so the RPCs are callable by plain HTTP 1.0 and 1.1 GET and POST.

You can try this server, it is a testbed where I experiment. Feel free to contact me to report bugs and ideas.

http://saltlake71.eu/urpc

[Josverl]

thanks , not interested in a subscription.
If I need such functionality then a Azure Function or AWS lambda (Each will provide me 1 million/year forever fee calls ) will allow more flexibility and privacy.

[massimosala]

I fix some bugs and in the help page add the parameters to call 'speak'. Now the function call is cached, so only the first call is slow.

NOTE
Some countries are blocked (too much bots...); if you are blocked write to me.

[shariltumin]

I got 403 Forbidden. Why not share your code on github. I am interested to have a look. Are you thinking about implementing microservices?

[massimosala]

Hi @shariltumin

Yes, I am implementing microservices. I am selling some of them, sorry I will not share the code.
Please write me which country you live: I will check the access policies and let you know.

[shariltumin]

OK, my best wishes.

[massimosala]

Thank you. Web hosting isn't free of charge.

[massimosala]

For the moment I removed the access control list on countries.

[massimosala]

The new version is online. I improved quite a lot the documentation of the available micro services.
http://saltlake71.eu/