Noob here, my first plugins...

[Haimana]

hello there,

I'm Seb, Romanian sailor, with some knowledge about electronics, mechanics and some software programming.
And also a happy user of SignalK and Openplotter. Many thanks for the authors.

For now, I'm trying to discover javascript, especially for SignalK applications and I started with a simple plugin which report the Raspberry Pi's uptime

After some struggling I managed to publish this plugin on github and npmjs.
My repo is here: https://github.com/Haimana/signalk-rpi-uptime

In the last version (v0.0.4) I tried to add an option for enabling/disabling the "pretty format uptime" reporting into SK and I could not figure out how to do it (to change it) without restarting SK.
I tried to figure out how the value of my boolean variable is passed through code. It seems is passed as I want only if change it and restarting SK.
I am wondering if there is some other way to write this code, which doesn't require restarting SK.

Please have mercy for my left-handed coding style. :) :) :)
Also, excuse my English, is not as good as I need.

Thank you,
Seb

[tkurki]

See https://github.com/SignalK/signalk-server/blob/master/docs/src/develop/plugins/server_plugin.md#start-coding , there's the section that describes the lifecycle methods start and stop:

• start is called for for enabled plugins when the server starts
• when you change the configuration the plugin is stopped by calling stop and then start is called again, but with the updated configuration values

Your code almos there, but it is not setting timer variable anywhere, so your stop function does not do anything.

[Haimana]

Thank you, is more clear now.

[sberl]

I see that this is an attempt to learn to code a plugin, that is great. If the intent is just to make the uptime visible, I suggest that it would be simpler and more convenient for user if this you added this one additional data path to the existing plugin https://github.com/sberl/signalk-rpi-monitor. If you create a PR I would be happy to merge it in. I am also seeing, from a specification point of view, that we are starting to create a bunch of paths that in name are specific to RPi, but are actually more general and could be applicable to any computer or microcontroller type device, and maybe the naming should take that into account. The path should also take into account that a particular signalk may have multiple instances of "computers" which each have their own uptime, CPU utilization, memory, storage, etc. It would be nice to standardize these path naming conventions. Steve

…

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-- -steve

[Haimana]

Yes, you are right, I am just start learning this...
Also, I am still learning and discovering how to work with git, github, npmjs and so on... My background is more related to Arduino and CNC milling machines.

So, if you'll give me some hints about PR... I'm in! Unfortunately, I didn't used git/github for complicated (for me) things like that so... :)
Totally agree about standardizing path naming

[Haimana]

Hello, me again :)

I'll use same conversation because still noob here and still have some issues with stopping and reloading one plugin.

I need a review for my plugin: https://github.com/Haimana/signalk-ble-heater.git

I made it for controlling a Chinese diesel heater which allow Bluetooth connection.
The biggest problems was related to stopping and reloading the plugin. I managed to fix these problems somehow, also using ChatGPT
But I am not very happy with the general structure of the code.
I had to use some variables to force the plugin to wait for stop before (re)start, especially when some parameters are changed, like polling interval, I had to make some functions "async" and I am not sure if this is OK with SignalK and so on...

But for now, this code seems to do it's job, it connects/disconnects to the Bluetooth device, read the values, start, stop etc.

Because I intend to go further and make it a webapp which will provide full control for this kind of heaters, I ask you nicely, please be so kind and take a look over my code.

Any advice and any critics will be very appreciated.
No mercy this time! :)

Thank you,
Seb

PS: My diesel heater controller looks like this:

[tkurki]

If you need to wait for something you could make what you are waiting on a Promise and wait on that with then. For example

const plugin = {}

let stopped = Promise.resolve()

plugin.start = async (options) => {
  console.log('start called')
  stopped.then(() => {
    console.log('starting')
  })
}
plugin.stop = async () => {
  console.log('stop called')
  stopped = new Promise(async (resolve) => {
    try {
      console.log('stopping')
      // do your async stopping actions
      await new Promise(resolve => setTimeout(resolve, 10* 1000))
    } finally {
      console.log('stopped')
      resolve()
    }
  })
}

//test it
setTimeout(plugin.start, 0)
setTimeout(plugin.stop, 0)
setTimeout(plugin.start, 0)

You can paste that into a browser console or Node prompt.

[Haimana]

wow, thank you for your instant reply
I'll test it for sure, thank you again

[Haimana]

sorry for telling you what you already know but... it work perfect! :)
thanks and fair winds