2009/5/11 Jean-Paul Calderone <exar...@divmod.com>
> On Mon, 11 May 2009 16:55:40 +0200, Luigi Conte <
> luigiandcosoluti...@gmail.com> wrote:
> >I'm sure you're saying only good things but I'm so inexpert in twisted
> that
> >I can't understand very well what to do.
> >I'll try to explain all that I want to do and how I did it wrongly:
> >first I have to call the connect method from the api and it returns a
> >deferred so I do:
> >in conn_to_ctrl i have:
> >d = api.connect(...)
> >return d
> >
> >now I do some operations with config files to call many times the start
> >method from the api (I have to start many virtual machines) and the
> >api.start returns a deferred so what have I to do now?
> >I do so:
> >in examinecfg i have:
> ># tha same d that i used to add api.connect!
> >self.d.addCallback(api.start, (method_args))
> >return d
> >
> >Then I have to call the disconnect method from the api. But i tried to
> print
> >out something to fallow the executing but I only see printing the first
> >method that call the connection. after that the process ends.
> >
> >In the main I have:
> >defer = conn_to_ctrl()
> >or have I to add to defer also the examinecfg?
> >
> >thank you very much
>
> I'm not sure what you're doing wrong. It's hard to understand mixed up
> snippets and fragments of code. Please:
>
> - don't top post
> - share complete, runnable examples (preferably minimal, too)
> - share the failure you're seeing - possibly including a traceback, or a
> description of the behavior that the program exhibits when you run it,
> and an explanation of how this differs from what you want
>
> Jean-Paul
>
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>
Ok I'll try to explain what the api provides to me and what I want to do
with it:
mothods provided by api that I want to use:
1) connection
def connect(self, ctrl_host, ctrl_port, user, passwd):
"""Connect to an Usher control server.
@param ctrl_host: fqdn where Usher controller is running
@type ctrl_host: string
@param ctrl_port: port number Usher controller is listening on
@type ctrl_port: int
@param user: username of user connecting to Usher controller
@type user: string
@param passwd: password of user connecting to Usher controller
@type passwd: string
return: Deferred which returns and L{UsherResult}
rtype: twisted.internet.defer.Deferred
"""
# serialize access to connect
if not self.connect_lock.acquire(False):
raise UsherEx, "Connection Pending"
if self.factory:
self.disconnect()
# reset vms
self.vms = {}
# reset passwd to None until we're connected
self.passwd = None
self.factory = APIFactory()
self.factory.api = self
# connect to server
reactor.connectSSL(ctrl_host, ctrl_port, self.factory,
ssl.ClientContextFactory())
d = self.factory.login(credentials.UsernamePassword(user, passwd),
client=self)
d.addErrback(self._handle_err, misc.whoami())
d.addCallback(self._connected_to_ctrl, ctrl_host, ctrl_port, user,
passwd)
return d
2) start single vm
def start(self, cluster=None, prefix='', vmlist=None, count=None,
first=None, last=None, dregex=None, dlist=None, dryrun=False, eid=None,
**kw):
"""Start a VM or set of VMs
@param cluster: Name of cluster to which VMs should belong
@type cluster: string
@param prefix: prefix to prepend to VM names
@type prefix: string
@param vmlist: list of strings of VMs to start
@type vmlist: list of strings
@param count: Number of consecutive VMs to start
@type count: int
@param first: Lowest number of VM to start
@type first: int
@param last: Highest number of VM to start
@type last: int
@param dregex: regular expression to match against destination LNM
names
@type dregex: list of strings
@param dlist: list of strings to match against destination LNM names
@type dlist: list of strings
@param dryrun: Show what would have happened if the command had been
run without the dryrun command (at the instant that the dryrun command was
run of course)
@type dryrun: bool
@param eid: mechanism for admin user to be able to specify an
alternate username for forming suffix for regex
@type eid: string
@param kw: Extra arguments passed to controller for use by plugins
or LNM. Any keywords starting with 'vm_' are added to VM's uargs
parameter. Note, the controller actually checks for two kw arguments: ram
and ip_addrs. Though these are, strictly speaking, VM parameters, they're
considered important enough that the controller checks for them.
@type kw: dict
@return: Deferred which returns an L{UsherResult}
@rtype: twisted.internet.defer.Deferred
@raise UsherNotConnected: Raised when not connected to Usher
Controller
@raise UsherPBDeadRefEx: Raised when capability for Usher Controller
goes stale. Must reconnect when this happens
@raise UsherInvalidInputEx: Raised when an invalid input or
combination of parameters is received.
"""
# make sure we're connected
if not self.aref:
raise UsherNotConnectedEx
# combine these to reduce params
if ((first and first < 0) or (last and last < 0) or (count and count
<
0)):
raise UsherInvalidInputEx("first, last, and count must be
non-negative")
vmrange = (first,last,count)
# arg check
self._arg_check(vmlist, vmrange)
# get final destination list
dlist = self._namecomplete(dlist, suffix=self.suffix)
self._check_lnmlist(dlist)
dregex = self._regex_append(dregex, dlist)
dlist = self._regex_filter(dregex, self.lnms.keys())
# complete names (if necessary) in the vmlist
vmlist = self._namecomplete(vmlist, cluster, eid)
# check that the vms specified don't already exist
self._check_vmlist(vmlist, isin=True)
vmlist = self._get_vm_names_to_start(vmlist, cluster, prefix,
vmrange, eid)
# controller handles eid from kw, so add it
if eid:
kw['eid'] = eid
if dryrun:
d = UsherResult('dryrun', msg = 'started:' + linesep +
linesep.join(vmlist))
return d
try:
if vmlist:
d = self.aref.callRemote("start", vmlist, dlist, **kw)
d.addErrback(self._handle_err, misc.whoami())
else:
raise UsherInvalidInputEx( "No VMs started. No unique VMs
specified in command")
return d
except pb.DeadReferenceError, ex: raise UsherPBDeadRefEx
in my script I have to use connect method and then I have to do some
operations first of calling the start method
1) start connection
def startConnection(self):
d = my_api.connect(self.ctrl_ip, self.ctrl_port, self.user,
self.pwd)
d.addCallback(self.postConnection)
d.addErrback(twisted.python.log.err)
print "Connection added"
return d
2) operation before starting a virtual machine:
def newVMCfg(self, new_vms_cfg):
#...
#some operations
#if condition valid I try to start the virtual machine
# is this the correct way to pass args to the start
method?
d = self.d.addCallback(self.startVM,(new_vm,
self.lnms[i])
print "started vm %s"%new_vm
return d
in the main process I call them as:
d = startConnection()
d.addCallback(newVMCfg, arg)
Is it correct? Because the process stops at the first method called: I see
only "connection added".
Thank you for your help!!
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