Thanks Johan for your appreciation: but most of the merit does not go to the
client (pyownet) but to the server (owserver). I’m really amazed how rock-solid
owserver can be.
Colin: the key point for using pyownet efficiently is to strictly have a single
proxy instance for the whole program. Creating on the fly proxy instances and
throwing them away after use is very inefficient.
Here a quick and dirty timing on a raspberry pi-2 running debian jessie (only
simulated devices, sorry, I have no access at home to a network of real
sensors).
>>> from pyownet.protocol import proxy
>>> p = proxy()
>>> float(p.read('/uncached/10.67C6697351FF/temperature'))
14.8957
>>> float(open('/run/1wire/uncached/10.67C6697351FF/temperature').read())
75.7942
>>> import timeit
>>> setup = "import pyownet.protocol; p = pyownet.protocol.proxy()"
>>> stmt = "t = float(p.read('/uncached/10.67C6697351FF/temperature'))"
>>> timeit.repeat(stmt, setup, number=1000)
[1.426529735999793, 1.430095917000017, 1.4105863439999666]
>>> setup = "import pyownet.protocol; p =
>>> pyownet.protocol.proxy(persistent=True)"
>>> stmt = "t = float(p.read('/uncached/10.67C6697351FF/temperature'))"
>>> timeit.repeat(stmt, setup, number=1000)
[0.9204462379998404, 0.8786001309999847, 0.8915852740001355]
>>> stmt = "t =
>>> float(open('/run/1wire/uncached/10.67C6697351FF/temperature').read())"
>>> timeit.repeat(stmt, number=1000)
[2.3116189530001066, 2.300803404999897, 2.280824553000002]
>>> setup = "import pyownet.protocol"
>>> stmt = "p = pyownet.protocol.proxy()"
>>> timeit.repeat(stmt, setup, number=1000)
[5.222551192000083, 5.203011117999722, 5.198920875000113]
So here I read a temperature from a simulated device, convert it to float and
store it. Times are as follows:
pyownet non persistent: 1.41 ms
pyownet persistent: 0.88 ms
owfs read: 2.28 ms
These are really small times (reading a real sensor would take for sure
longer), but nevertheless I do not expect that pyownet should be any slower
than owfs access. Note however that creating a proxy instance takes about 5.2
ms so this operation should be done only once in the lifetime of the program.
Stefano
> On 20 May 2015, at 09:47, Colin Reese <colin.re...@gmail.com> wrote:
>
> Interesting data point, and makes me want to take another look. I have both
> implementations written up and ended up using os.walk on owfs dir as I found
> it fastest, despite having to write more code around it (obviously).
>
> Colin
>
>
> On 5/20/2015 12:26 AM, Johan Ström wrote:
>> Hi,
>>
>> just want to give +1 for pyownet. I'm using it for my network and it works
>> 100% flawless, scanning the alarm dir ~10 times per second and the full bus
>> every 30 second, reading ~25 temperature sensors every 30 seconds.
>>
>> This have been running for about a year now, using my own master software
>> which was designed for a mixed network with slow but powered temperature
>> sensors and "quick" PIO-devices (such as DS2406), where it is important to
>> service any PIO input changes quickly (alarm + latch):
>> https://github.com/stromnet/pyowmaster
>> <https://github.com/stromnet/pyowmaster>
>>
>> I have not yet tested the socket persistence though, that is on my todo-list!
>>
>> Johan
>>
>> On 20/05/15 09:16, Stefano Miccoli wrote:
>>> Let me answer to the python part of your question.
>>>
>>> To access 1-wire sensors from a python script you have two options:
>>>
>>> A) install the owserver daemon and access 1-wire data via the owserver
>>> protocol (aka ownet), see http://owfs.org/index.php?page=owserver-protocol
>>> <http://owfs.org/index.php?page=owserver-protocol>
>>> B) directly access the “physical bus” from your script.
>>>
>>> Let discuss the two approaches.
>>>
>>>
>>> A) access via owserver.
>>>
>>> The owserver protocol is a TCP network protocol. In python you can use
>>> either a pure python implementation, or link to an external C library that
>>> implements the protocol.
>>>
>>> As what regards pure python there are two options:
>>>
>>> ownet from the official distribution
>>> pyownet, available on pypi https://pypi.python.org/pypi/pyownet
>>> <https://pypi.python.org/pypi/pyownet> (pip install pyownet) with docs
>>> here: http://pyownet.readthedocs.org/en/latest/#
>>> <http://pyownet.readthedocs.org/en/latest/#>
>>>
>>> (I wrote pyownet to improve the official implementation, which is not more
>>> maintained on pipy where it stuck at version 0.2 of 2006-12-15)
>>>
>>> Alternatively you can go for a binary library binding, which will introduce
>>> a run time dependency to libow
>>>
>>> ow from the official distribution
>>> pyowfs, available on pypi https://pypi.python.org/pypi/pyowfs
>>> <https://pypi.python.org/pypi/pyowfs> (pip install pyowfs) with docs here:
>>> http://priesch.co.at/pyowfs <http://priesch.co.at/pyowfs>
>>>
>>>
>>> In the case of the owserver protocol I would suggest using one of the two
>>> pure python implementations: bottleneck is usually the 1-wire bus, so there
>>> is no need to go to a C implementation of the TCP protocol. Performance is
>>> fairly good with both ownet and pyownet, with a slight edge on pyownet,
>>> with implements socket persistence and is actively maintained. (OK, this is
>>> the developer view.)
>>>
>>>
>>> B) direct access to the bus.
>>>
>>> This is not possible with pure python so you have to go with one of the two
>>> C API bindings (the official ow or pyowfs). I have no experience with this
>>> approach (I always install owserver first) so I can’t give informed advice.
>>> However I would first try pyowfs since it is maintained on pypi.
>>>
>>>
>>>
>>> Bye
>>>
>>> Stefano
>>>
>>>> On 20 May 2015, at 00:49, DavidJ61 <davejohn...@gmail.com
>>>> <mailto:davejohn...@gmail.com>> wrote:
>>>>
>>>> Further to my above message, I am having a bit of a problem accessing the
>>>> pressure attribute for the EDS environment sensor EDS0066. I have trawled
>>>> google and am not able to find any documentation on how I can do this. In
>>>> fact, as a whole, I have found this to be the case with owpython and it
>>>> seems I am missing my crystal ball.
>>>> I'd appreciate a bit of help and guidance.
>>>>
>>>>
>>>>
>>>> --
>>>> View this message in context:
>>>> http://owfs-developers.1086194.n5.nabble.com/owpython-tp5410p11354.html
>>>> <http://owfs-developers.1086194.n5.nabble.com/owpython-tp5410p11354.html>
>>>> Sent from the OWFS Developers mailing list archive at Nabble.com
>>>> <http://nabble.com/>.
>>>>
>>>> ------------------------------------------------------------------------------
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>>>
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>>>
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>>
>>
>>
>> ------------------------------------------------------------------------------
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>> Widest out-of-the-box monitoring support with 50+ applications
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