Re: [Xen-devel] [Patch] Fix 'Example interactive session' in docs/xen-api/wire-protocol.tex

[Keir Fraser <keir.fraser@xxxxxxxxxxxxx>]

I'll apply it if you send as an attachment. Your mail client line-wrapped
the patch.

 -- Keir

On 12/07/2009 21:13, "Andreas Florath" <xen@xxxxxxxxxxxx> wrote:

> Hello!
> 
> In the section 'Example inteactive session' in the XenAPI documentation
> the example(s) just don't work.
> 
> I tried to fix the problems and added some hints.
> 
> What do you think about the patch? Any hints are welcome!
> 
> Kind regards
> 
> Andreas Florath
> 
> Signed-off-by: Andreas Florath <xen@xxxxxxxxxxxx>
> 
> 
> 
> # HG changeset patch
> # User Andreas Florath <xen@xxxxxxxxxxxx>
> # Date 1247217566 -7200
> # Node ID 5b89bfefa6668213899424341eb851bb34259461
> # Parent  d6c1d7992f437c625135c2f8752fc94078ec4c31
> docs/xenapi: Update examples section reflecting the current behaviour.
> 
> diff -r d6c1d7992f43 -r 5b89bfefa666 docs/xen-api/wire-protocol.tex
> --- a/docs/xen-api/wire-protocol.tex    Wed Jul 08 22:08:31 2009 +0100
> +++ b/docs/xen-api/wire-protocol.tex    Fri Jul 10 11:19:26 2009 +0200
> @@ -1,5 +1,6 @@
>  %
>  % Copyright (c) 2006-2007 XenSource, Inc.
> +% Copyright (c) 2009 flonatel GmbH & Co. KG
>  %
>  % Permission is granted to copy, distribute and/or modify this document
> under
>  % the terms of the GNU Free Documentation License, Version 1.2 or any later
> @@ -9,6 +10,7 @@
>  % "GNU Free Documentation License" or the file fdl.tex.
>  %
>  % Authors: Ewan Mellor, Richard Sharp, Dave Scott, Jon Harrop.
> +% Contributor: Andreas Florath
>  %
>  
>  \section{Wire Protocol for Remote API Calls}
> @@ -229,76 +231,153 @@
>  Note that, in order to get a consistent snapshot of a task's state, it
> is advisable to call the ``get\_record'' function.
>  
>  \section{Example interactive session}
> +This section describes how an interactive session might look, using
> +the python API.  All python versions starting from 2.4 should work.
>  
> -This section describes how an interactive session might look, using the
> python
> -XML-RPC client library.
> +The examples in this section use a remote Xen host with the ip address
> +of \texttt{192.168.7.20} and the xmlrpc port \texttt{9363}.  No
> +authentication is used.
>  
> -First, initialise python and import the library {\tt xmlrpclib}:
> +Note that the remote server must be configured in the way, that it
> +accepts remote connections.  Some lines must be added to the
> +xend-config.sxp configuration file:
> +\begin{verbatim}
> +(xen-api-server ((9363 none)
> +                 (unix none)))
> +(xend-tcp-xmlrpc-server yes)
> +\end{verbatim}
> +The xend must be restarted after changing the configuration.
> +
> +Before starting python, the \texttt{PYTHONPATH} must be set that the
> +\texttt{XenAPI.py} can be found.  Typically the \texttt{XenAPI.py} is
> +installed with one of the Xen helper packages which the last part of
> +the path is \texttt{xen/xm/XenAPI.py}.
> +
> +Example: Under Debian 5.0 the package which contains the
> +\texttt{XenAPI.py} is \texttt{xen-utils-3.2-1}. \texttt{XenAPI.py} is
> +located in \texttt{/usr/lib/xen-3.2-1/lib/python/xen/xm}. The
> +following command will set the \texttt{PYTHONPATH} environment
> +variable in a bash:
>  
>  \begin{verbatim}
> -\$ python2.4
> -...
> ->>> import xmlrpclib
> +$ export PYTHONPATH=/usr/lib/xen-3.2-1/lib/python
>  \end{verbatim}
>  
> -Create a python object referencing the remote server:
> +Then python can be started and the XenAPI must be imported:
>  
>  \begin{verbatim}
> ->>> xen = xmlrpclib.Server("http://test:4464";)
> +$ python
> +...
> +>>> import xen.xm.XenAPI
>  \end{verbatim}
>  
> -Acquire a session token by logging in with a username and password
> -(error-handling omitted for brevity; the session token is pointed to by the
> -key {\tt 'Value'} in the returned dictionary)
> -
> +To create a session to the remote server, the
> +\texttt{xen.xm.XenAPI.Session} constructor is used:
>  \begin{verbatim}
> ->>> session = session.login_with_password("user", "passwd")['Value']
> +>>> session = xen.xm.XenAPI.Session("http://192.168.7.20:9363";)
>  \end{verbatim}
>  
> -When serialised, this call looks like the following:
> +For authentication with a username and password the
> +\texttt{login\_with\_password} is used:
> +\begin{verbatim}
> +>>> session.login_with_password("", "")
> +\end{verbatim}
>  
> +When serialised, this call looks like:
>  \begin{verbatim}
> +POST /RPC2 HTTP/1.0
> +Host: 192.168.7.20:9363
> +User-Agent: xmlrpclib.py/1.0.1 (by www.pythonware.com)
> +Content-Type: text/xml
> +Content-Length: 221
> +
>  <?xml version='1.0'?>
>  <methodCall>
> -  <methodName>session.login_with_password</methodName>
> -  <params>
> -    <param>
> -      <value><string>user</string></value>
> -    </param>
> -    <param>
> -      <value><string>passwd</string></value>
> -    </param>
> -  </params>
> +<methodName>session.login_with_password</methodName>
> +<params>
> +<param>
> +<value><string></string></value>
> +</param>
> +<param>
> +<value><string></string></value>
> +</param>
> +</params>
>  </methodCall>
>  \end{verbatim}
>  
> -Next, the user may acquire a list of all the VMs known to the host:
> (Note the
> -call takes the session token as the only parameter)
> +And the response:
> +\begin{verbatim}
> +HTTP/1.1 200 OK
> +Server: BaseHTTP/0.3 Python/2.5.2
> +Date: Fri, 10 Jul 2009 09:01:27 GMT
> +Content-Type: text/xml
> +Content-Length: 313
> +
> +<?xml version='1.0'?>
> +<methodResponse>
> +<params>
> +<param>
> +<value><struct>
> +<member>
> +<name>Status</name>
> +<value><string>Success</string></value>
> +</member>
> +<member>
> +<name>Value</name>
> +<value><string>68e3a009-0249-725b-246b-7fc43cf4f154</string></value>
> +</member>
> +</struct></value>
> +</param>
> +</params>
> +</methodResponse>
> +\end{verbatim}
> +
> +Next, the user may acquire a list of all the VMs known to the host:
>  
>  \begin{verbatim}
> ->>> all_vms = host.get_resident_VMs(session)['Value']
> ->>> all_vms
> -['OpaqueRef:1', 'OpaqueRef:2', 'OpaqueRef:3', 'OpaqueRef:4' ]
> +>>> vms = session.xenapi.VM.get_all()
> +>>> vms
> +['00000000-0000-0000-0000-000000000000',
> 'b28e4ee3-216f-fa85-9cae-615e954dbbe7']
>  \end{verbatim}
>  
> -The VM references here have the form {\tt OpaqueRef:X}, though they may
> not be
> -that simple in the future, and you should treat them as opaque strings.
> -Once a reference to a VM has been acquired a lifecycle operation may be
> invoked:
> +The VM references here have the form of an uuid, though they may
> +change in the future, and they should be treated as opaque strings.
>  
> +Some examples of using accessors for object fields:
>  \begin{verbatim}
> ->>> xen.VM.start(session, all_vms[3], False)
> -{'Status': 'Failure', 'ErrorDescription': ['VM_BAD_POWER_STATE',
> 'Halted', 'Running']}
> +>>> session.xenapi.VM.get_name_label(vms[1])
> +'guest002'
> +>>> session.xenapi.VM.get_actions_after_reboot(vms[1])
> +'restart'
> +\end{verbatim}
> +
> +Grab the actual memory and cpu utilisation of one vm:
> +\begin{verbatim}
> +>>> m = session.xenapi.VM.get_metrics(vms[1])
> +>>> session.xenapi.VM_metrics.get_memory_actual(m)
> +'268435456'
> +>>> session.xenapi.VM_metrics.get_VCPUs_utilisation(m)
> +{'0': 0.00041759955632935362}
> +\end{verbatim}
> +(The virtual machine has about 256 MByte RAM and is idle.)
> +
> +Pausing and unpausing a vm:
> +\begin{verbatim}
> +>>> session.xenapi.VM.pause(vms[1])
> +''
> +>>> session.xenapi.VM.unpause(vms[1])
> +''
> +\end{verbatim}
> +
> +Trying to start an vm:
> +\begin{verbatim}
> +>>> session.xenapi.VM.start(vms[1], False)
> +...
> +: Xen-API failure: ['VM_BAD_POWER_STATE', \
> +    'b28e4ee3-216f-fa85-9cae-615e954dbbe7', 'Halted', 'Running']
>  \end{verbatim}
>  
>  In this case the {\tt start} message has been rejected, because the VM is
>  already running, and so an error response has been returned.  These
> high-level
>  errors are returned as structured data (rather than as XML-RPC faults),
> -allowing them to be internationalised.  Finally, here are some examples of
> -using accessors for object fields:
> -
> -\begin{verbatim}
> ->>> xen.VM.get_name_label(session, all_vms[3])['Value']
> -'SMP'
> ->>> xen.VM.get_name_description(session, all_vms[3])['Value']
> -'Debian for Xen'
> -\end{verbatim}
> +allowing them to be internationalised.
> 
> 
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