

Show HN: I've used Go to build a daemon for the Raspberry Pi - jondot
http://jondot.github.io/groundcontrol/

======
pothibo
Cool! Go is getting some attention. Project looks very neat.

I just released an alpha project for the Raspberry pi using Go for controlling
your sprinklers.

Shameless plug: <https://github.com/pothibo/irrigation>

~~~
burntsushi
Sweet!

But make it go-gettable, dammit. :-) [1]

Also, is there anything I could read that would explain how I'd hook up my RPi
to my sprinkler system? Thanks!

[1] - <https://github.com/pothibo/irrigation/issues/1>

~~~
pothibo
Didn't see your question. opensprinkler.com seems like a verygood solution. I
found it after starting working on my project so I bought a sainsmart 5v relay
controller. Doing it again, I would probably buy opensprinkler for Pi

~~~
burntsushi
Excellent. Thanks very much for the thread. I'll pull on it soon, hopefully.

------
omerh
Already tried using it, setup was a breeze, and already reporting to my
Librato metrics.

Nice job

------
manacit
This is a great little program, but I'm curious why you're marketing it only
for the Raspberry Pi? A low-memory system monitoring script could be useful in
many other areas, and as far as I can tell, there's nothing RPi specific in
the source.

~~~
jondot
Thanks!

Well, I'm not saying it is only for the Pi (took care of adding it into the
FAQ recently), just that it's been run and tested on one for more than two
weeks now - so I feel comfortable with saying it works great on the Pi.

But yes - I have been building and testing it on OSX and Linux alternatively,
before deploying on the Pi for testing, so it is perfectly suitable for any
unix device with low resources indeed.

Hope it works well for you anywhere you want to run it :)

------
natch
Nice but I wish people wouldn't use names like "w", "tuple" or "string" for
variables. Tuple of what? The analysis that is needed for the reader to figure
that out, however short, is friction you are adding to the code readability.
The shame of it is this kind of friction is totally unnecessary. Looking
forward to giving this a whirl though.

~~~
jondot
Yup. Ironically, I'm a big advocate of good naming in production code.

Unfortunately what the git logs don't show is that some of that code was
written very late at night (where my spare time lives), and sometimes I
neglected to do that out of sheer tiredness.

I will definitely try to improve on that when needed, thanks!

~~~
natch
Wow, thanks for the positive reaction to my comments. A breath of fresh air.

------
Osmium
Very cool! Looking forward to trying it out. My current solution had been a
dead-simple crontab script that pushed some stats to a static html page every
hour. It's ugly and a little dumb so I'd been looking for a better solution,
and this looks perfect.

~~~
krenel
Hey, I have a project similar to groundcontrol but un Python, is called
RaspCTL[1][2]. You add/execute commands thru a web interface, radio support
(using mpd), can manage the daemons, dashboard with the memory
usage/processes, processor temperature, etc...

And just right now I'm working on an alarm system, where you'll be able to
launch any arbitrary commands or start/stop playing a radio. In a few days
I'll release the new version.

BTW, for the ones who have a dynamic IP and want to use a Dynamic DNS service
for being able to access to your RPi from the internet, you can check this
out[3].

[1] Official site: <http://raspctl.com/> [2] Repository:
<http://code.krenel.org/raspctl> [3] <http://ip.raspctl.com/>

------
stevelaz
I wonder what the binary size, resource utilization, and performance
difference would be if this was written in C. How would Go match up against C
for embedded platform dev? I mean small/real embedded systems... not
Android/iPhone platforms.

~~~
gravitronic
Go's standard library includes things needed for the Real World(tm) like HTTP
server/client and serialization for example on a project like this one.

In C those functions would be provided by third party libraries like libCURL
(or handwritten and likely insecure).

This is slightly irrelevant in terms of your question about performance, but
in terms of dev it is very nice to avoid dealing with 3rd party packages,
especially when programming for multiple architectures.

~~~
stevelaz
Yes, of course C doesn't have all the bloat that comes with Go. But still, my
question was about performance (as you noted). :)

LibCURL is used (along with a TON of other 3rd party C libs) in a bunch of
systems securely. Writing C code isn't __always__ insecure. It all depends on
the developer/team. Just like writing Java isn't always portable.

It seems like it's all about saving dev time these days. I was once pulled
onto a project where some devs had used perl & python for an embedded system.
They got a prototype system up pretty quickly, but performance just wasn't
there and they were using WAY too much RAM/CPU based on what the system had to
offer. They wasted many man-months trying to optimize their code. Eventually,
they brought in some C devs and we rewrote in C and the system ran great. It
turned out great for the Python/Perl devs too because they got to learn C and
some of the benefits of using it.

Don't get me wrong. C doesn't fit all problems.

~~~
dpritchett
So they proved out the first version in a high level dynamic language and then
someone reimplemented in C for performa performance reasons? Sounds like a
solid process.

~~~
stass
I actually deployed a production embedded system running a large chunk of code
written in perl once (on a 180MHz FreeBSD/arm board). The performance was just
enough, although the critical components were implemented in C.

------
fegu
Just to save some time for FreeBSDers, this does not run on Raspberry Pi's
with FreeBSD out of the box: ELF binary type "0" not known (and branding it
does not help - it needs the linux compat lib - anyone have that on a
raspberry?).

------
outside1234
Very cool! There are a wide range of applications for embedding devices like
the RPi going places where they are installed and forgotten, often in very
inaccessible places. Projects like this are a key part of making that happen.

I've been working on an open source project like this for JavaScript called
Nitrogen. You can read about it here if you are interested in a
node.js/JavaScript take on this: <http://bit.ly/18k67ow>

~~~
jondot
Thanks! the major selling point of Go over Node.js on the Pi for me was
resource usage. I definitely share your excitement for the internet of things,
hope I can dig deeper into Nitrogen over the weekend :)

------
0x0
Isn't the rpi an armv6 device? Why the GOARM=5 build flag?

------
danieldrehmer
I'll build 'Major Tom', a mobile app making use of this

~~~
jondot
Sounds like a great idea :)

------
jameswyse
This looks awesome!

How easy would it be to add support for statsd[1] / graphite[2]?

[1] <https://github.com/etsy/statsd/> [2] <http://graphite.wikidot.com/>

------
secure
I’m all in for using Go and having fun, but is there an actual point in this
daemon? I thought the Raspberry Pi is about making life easier and not about
adding one more device to constantly worry about (i.e. check the stats every
so often or get alerts)? :-)

~~~
stinos
This is probably made for fun, and in the spirit of the times where there's an
app for everything. Whether or not it's useful is another point though..

~~~
jondot
Author here.

It was made out of several reasons

* For fun (as said here)

* Scratching my own itch - I needed a way to remotely run commands though a nice UI, and a way to see how my Pi is doing when i'm not at home.

* For lack of better tooling - every thing I evaluated needed a combination of things, no other tool gave me all-in-one. This made the resources bloated. With GC, you get around 3-4MB RSS.

* To prove to myself that Go can be as great for development on the Pi as Python (which many people use there)

I also like the idea of Internet of Things
<http://en.wikipedia.org/wiki/Internet_of_Things>

I already had everything working in an evening based on a concept I had, and
it took additional few days of my spare time to get a nice looking UI, landing
page, code cleaned up, supporting more reporters etc.

So all in all I invested that additional time on the premise that others may
find it useful to make their own life a bit easier -- naively speaking, if it
make your life harder please let me know why so I can improve it :)

------
ambrop7
How is this specific to Raspberry Pi in any way?

~~~
stevelaz
From my brief browsing of the code, it doesn't see to be tied to Raspberry Pi.
Or if it is, it's probably very portable to other Linux systems.

~~~
jondot
Not specific, it _can_ work on unix like OSes. Using it both on my Pi and on
my Mac and Linux for testing :)

However being that it has very slim resources and an easy way to cross
compile, it is perfect for the Pi.

