[Pympi-users] And now for something completely different

[Julian C. <rjc...@cs...>]

Web Services and pyMPI:

Recently (that would be this w/e) I looked at how to set up a web service in
python. The major reason was to make code written on python available from
other platforms, especially Windows and Excel.

I installed SOAPpy 0.12 (http://pywebsvcs.sourceforge.net/) on both windows
and Solaris and suffice to say, it's very easy to use python client to
python server. SOAPpy handles all the complexity for you. The real
complexity was having to use WSDL descriptor files to be able to call python
servers from Excel (Using MS SoapClient 3.0). Basically on Windows, you
have? to use a WSDL and you need to use namespaces or it doesn't work.
Effectively, you have to pre-define all functions, inputs and outputs in the
WSDL file.

Now to the point:
You probably aren't shocked to find out that I was able to get pyMPI to act
as a soap server. My reasoning was simple: why wait 10 seconds to run
something on windows, when I can run the same thing in 1 second on pyMPI?
Below is a simple example of pyMPI running at np 1, generating and returning
a short array of random numbers to a soap client. The printout is from the
client side.

Issues:
The major issue that occurs to me regarding pyMPI is that most parallel
scripts are by nature long running processes. This conflicts with the nature
of a server, which is supposed to handle multiple clients and multiple tasks
simultaneously. This suggests that the server itself would have to either
queue requests or manage the slave processes. That seems to add a lot of
complexity.
Anyway let me know if you think it has any utility for you.

regards

Julian Cook

>>> # Call a pyMPI soap server
>>> import SOAPpy
>>> server = SOAPpy.SOAPProxy("http://brahma:8007/",namespace = "python-os")
>>> seed = 69069
>>> server.config.dumpSOAPIn = 1 # debugging flag
>>> list = server.ArrayOfFloats(seed)
*** Incoming SOAP ******************************************************
<?xml version="1.0" encoding="UTF-8"?>
<SOAP-ENV:Envelope
  SOAP-ENV:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/"
  xmlns:SOAP-ENC="http://schemas.xmlsoap.org/soap/encoding/"
  xmlns:xsi="http://www.w3.org/1999/XMLSchema-instance"
  xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/"
  xmlns:xsd="http://www.w3.org/1999/XMLSchema"
>
<SOAP-ENV:Body>
<ArrayOfFloatsResponse SOAP-ENC:root="1">
<Result SOAP-ENC:arrayType="xsd:double[10]" xsi:type="SOAP-ENC:Array">
<item>0.70316610192589002</item>
<item>0.37607240403594255</item>
<item>0.018328414124517245</item>
<item>0.87040174120950486</item>
<item>0.20098065818385713</item>
<item>0.52939641382095703</item>
<item>0.68237564433556841</item>
<item>0.076620094609716638</item>
<item>0.50193267461011581</item>
<item>0.53994633368761047</item>
</Result>
</ArrayOfFloatsResponse>
</SOAP-ENV:Body>
</SOAP-ENV:Envelope>
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