Group

Group class

class PyTango.Group(name)

A Tango Group represents a hierarchy of tango devices. The hierarchy may have more than one level. The main goal is to group devices with same attribute(s)/command(s) to be able to do parallel requests.

add(self, subgroup, timeout_ms=-1) → None

Attaches a (sub)_RealGroup.

To remove the subgroup use the remove() method.

Parameters:
subgroup:(str)
timeout_ms:(int) If timeout_ms parameter is different from -1, the client side timeout associated to each device composing the _RealGroup added is set to timeout_ms milliseconds. If timeout_ms is -1, timeouts are not changed.
Return:

None
Throws:

TypeError, ArgumentError

add(self, patterns, timeout_ms=-1) -> None

Attaches any device which name matches one of the specified patterns.

This method first asks to the Tango database the list of device names matching one the patterns. Devices are then attached to the group in the order in which they are returned by the database.

Any device already present in the hierarchy (i.e. a device belonging to the group or to one of its subgroups), is silently ignored but its client side timeout is set to timeout_ms milliseconds if timeout_ms is different from -1.

Parameters:
patterns:(str | sequence<str>) can be a simple device name or a device name pattern (e.g. domain_*/ family/member_*), or a sequence of these.
timeout_ms:(int) If timeout_ms is different from -1, the client side timeouts of all devices matching the specified patterns are set to timeout_ms milliseconds.
Return:

None
Throws:

TypeError, ArgumentError
command_inout(self, cmd_name, forward=True) → sequence<GroupCmdReply>

command_inout (self, cmd_name, param, forward=True) -> sequence<GroupCmdReply>

command_inout (self, cmd_name, param_list, forward=True) -> sequence<GroupCmdReply>

Just a shortcut to do:
self.command_inout_reply(self.command_inout_asynch(...))
Parameters:
cmd_name:(str) Command name
param:(any) parameter value
param_list:(PyTango.DeviceDataList) sequence of parameters. When given, it’s length must match the group size.
forward:(bool) If it is set to true (the default) request is forwarded to subgroups. Otherwise, it is only applied to the local set of devices.
Return:

(sequence<GroupCmdReply>)
command_inout_asynch(self, cmd_name, forget=False, forward=True, reserved=-1) → int

command_inout_asynch (self, cmd_name, param, forget=False, forward=True, reserved=-1 ) -> int

command_inout_asynch (self, cmd_name, param_list, forget=False, forward=True, reserved=-1 ) -> int

Executes a Tango command on each device in the group asynchronously. The method sends the request to all devices and returns immediately. Pass the returned request id to Group.command_inout_reply() to obtain the results.
Parameters:
cmd_name:(str) Command name
param:(any) parameter value
param_list:(PyTango.DeviceDataList) sequence of parameters. When given, it’s length must match the group size.
forget:(bool) Fire and forget flag. If set to true, it means that no reply is expected (i.e. the caller does not care about it and will not even try to get it)
forward:(bool) If it is set to true (the default) request is forwarded to subgroups. Otherwise, it is only applied to the local set of devices.
reserved:(int) is reserved for internal purpose and should not be used. This parameter may disappear in a near future.
Return:

(int) request id. Pass the returned request id to Group.command_inout_reply() to obtain the results.
Throws:
command_inout_reply(self, req_id, timeout_ms=0) → sequence<GroupCmdReply>
Returns the results of an asynchronous command.
Parameters:
req_id:(int) Is a request identifier previously returned by one of the command_inout_asynch methods
timeout_ms:(int) For each device in the hierarchy, if the command result is not yet available, command_inout_reply wait timeout_ms milliseconds before throwing an exception. This exception will be part of the global reply. If timeout_ms is set to 0, command_inout_reply waits “indefinitely”.
Return:

(sequence<GroupCmdReply>)
Throws:
contains(self, pattern, forward=True) → bool
Parameters:
pattern:(str) The pattern can be a fully qualified or simple group name, a device name or a device name pattern.
forward:(bool) If fwd is set to true (the default), the remove request is also forwarded to subgroups. Otherwise, it is only applied to the local set of elements.
Return:

(bool) Returns true if the hierarchy contains groups and/or devices which name matches the specified pattern. Returns false otherwise.
Throws:
disable(*args, **kwds)

Disables a group or a device element in a group.

enable(*args, **kwds)

Enables a group or a device element in a group.

get_device(self, dev_name) → DeviceProxy

get_device (self, idx) -> DeviceProxy

Returns a reference to the specified device or None if there is no device by that name in the group. Or, returns a reference to the “idx-th” device in the hierarchy or NULL if the hierarchy contains less than “idx” devices.

This method may throw an exception in case the specified device belongs to the group but can’t be reached (not registered, down...). See example below:

try:
    dp = g.get_device("my/device/01")
    if dp is None:
        # my/device/01 does not belong to the group
        pass
except DevFailed, f:
    # my/device/01 belongs to the group but can't be reached
    pass

The request is systematically forwarded to subgroups (i.e. if no device named device_name could be found in the local set of devices, the request is forwarded to subgroups).

Parameters:
dev_name:(str) Device name.
idx:(int) Device number.
Return:

(DeviceProxy) Be aware that this method returns a different DeviceProxy referring to the same device each time. So, do not use it directly for permanent things.
Example:
# WRONG: The DeviceProxy will quickly go out of scope
# and disappear (thus, the event will be automatically
# unsubscribed)
g.get_device("my/device/01").subscribe_events('attr', callback)

# GOOD:
dp = g.get_device("my/device/01")
dp.subscribe_events('attr', callback)
Throws:

DevFailed
get_device_list(self, forward=True) → sequence<str>

Considering the following hierarchy:

g2.add("my/device/04")
g2.add("my/device/05")

g4.add("my/device/08")
g4.add("my/device/09")

g3.add("my/device/06")
g3.add(g4)
g3.add("my/device/07")

g1.add("my/device/01")
g1.add(g2)
g1.add("my/device/03")
g1.add(g3)
g1.add("my/device/02")

The returned vector content depends on the value of the forward option. If set to true, the results will be organized as follows:

    dl = g1.get_device_list(True)

dl[0] contains "my/device/01" which belongs to g1
dl[1] contains "my/device/04" which belongs to g1.g2
dl[2] contains "my/device/05" which belongs to g1.g2
dl[3] contains "my/device/03" which belongs to g1
dl[4] contains "my/device/06" which belongs to g1.g3
dl[5] contains "my/device/08" which belongs to g1.g3.g4
dl[6] contains "my/device/09" which belongs to g1.g3.g4
dl[7] contains "my/device/07" which belongs to g1.g3
dl[8] contains "my/device/02" which belongs to g1

If the forward option is set to false, the results are:

    dl = g1.get_device_list(False);

dl[0] contains "my/device/01" which belongs to g1
dl[1] contains "my/device/03" which belongs to g1
dl[2] contains "my/device/02" which belongs to g1
Parameters:
forward:(bool) If it is set to true (the default), the request is forwarded to sub-groups. Otherwise, it is only applied to the local set of devices.
Return:

(sequence<str>) The list of devices currently in the hierarchy.
Throws:
get_fully_qualified_name(*args, **kwds)

Get the complete (dpt-separated) name of the group. This takes into consideration the name of the group and its parents.

get_name(*args, **kwds)

Get the name of the group. Eg: Group(‘name’).get_name() == ‘name’

get_size(self, forward=True) → int
Parameters:
forward:(bool) If it is set to true (the default), the request is forwarded to sub-groups.
Return:

(int) The number of the devices in the hierarchy
Throws:
is_enabled(*args, **kwds)

Check if a group is enabled. New in PyTango 7.0.0

name_equals(*args, **kwds)

New in PyTango 7.0.0

name_matches(*args, **kwds)

New in PyTango 7.0.0

ping(self, forward=True) → bool
Ping all devices in a group.
Parameters:
forward:(bool) If fwd is set to true (the default), the request is also forwarded to subgroups. Otherwise, it is only applied to the local set of devices.
Return:

(bool) This method returns true if all devices in the group are alive, false otherwise.
Throws:
read_attribute(self, attr_name, forward=True) → sequence<GroupAttrReply>
Just a shortcut to do:
self.read_attribute_reply(self.read_attribute_asynch(...))
read_attribute_asynch(self, attr_name, forward=True, reserved=-1) → int
Reads an attribute on each device in the group asynchronously. The method sends the request to all devices and returns immediately.
Parameters:
attr_name:(str) Name of the attribute to read.
forward:(bool) If it is set to true (the default) request is forwarded to subgroups. Otherwise, it is only applied to the local set of devices.
reserved:(int) is reserved for internal purpose and should not be used. This parameter may disappear in a near future.
Return:

(int) request id. Pass the returned request id to Group.read_attribute_reply() to obtain the results.
Throws:
read_attribute_reply(self, req_id, timeout_ms=0) → sequence<GroupAttrReply>
Returns the results of an asynchronous attribute reading.
Parameters:
req_id:(int) a request identifier previously returned by read_attribute_asynch.
timeout_ms:(int) For each device in the hierarchy, if the attribute value is not yet available, read_attribute_reply wait timeout_ms milliseconds before throwing an exception. This exception will be part of the global reply. If timeout_ms is set to 0, read_attribute_reply waits “indefinitely”.
Return:

(sequence<GroupAttrReply>)
Throws:
read_attributes(self, attr_names, forward=True) → sequence<GroupAttrReply>
Just a shortcut to do:
self.read_attributes_reply(self.read_attributes_asynch(...))
read_attributes_asynch(self, attr_names, forward=True, reserved=-1) → int
Reads the attributes on each device in the group asynchronously. The method sends the request to all devices and returns immediately.
Parameters:
attr_names:(sequence<str>) Name of the attributes to read.
forward:(bool) If it is set to true (the default) request is forwarded to subgroups. Otherwise, it is only applied to the local set of devices.
reserved:(int) is reserved for internal purpose and should not be used. This parameter may disappear in a near future.
Return:

(int) request id. Pass the returned request id to Group.read_attributes_reply() to obtain the results.
Throws:
read_attributes_reply(self, req_id, timeout_ms=0) → sequence<GroupAttrReply>
Returns the results of an asynchronous attribute reading.
Parameters:
req_id:(int) a request identifier previously returned by read_attribute_asynch.
timeout_ms:(int) For each device in the hierarchy, if the attribute value is not yet available, read_attribute_reply ait timeout_ms milliseconds before throwing an exception. This exception will be part of the global reply. If timeout_ms is set to 0, read_attributes_reply waits “indefinitely”.
Return:

(sequence<GroupAttrReply>)
Throws:
remove_all(self) → None

Removes all elements in the _RealGroup. After such a call, the _RealGroup is empty.

set_timeout_millis(self, timeout_ms) → bool
Set client side timeout for all devices composing the group in milliseconds. Any method which takes longer than this time to execute will throw an exception.
Parameters:
timeout_ms:(int)
Return:

None
Throws:

(errors are ignored)

New in PyTango 7.0.0

write_attribute(self, attr_name, value, forward=True, multi=False) → sequence<GroupReply>
Just a shortcut to do:
self.write_attribute_reply(self.write_attribute_asynch(...))
write_attribute_asynch(self, attr_name, value, forward=True, multi=False) → int
Writes an attribute on each device in the group asynchronously. The method sends the request to all devices and returns immediately.
Parameters:
attr_name:(str) Name of the attribute to write.
value:(any) Value to write. See DeviceProxy.write_attribute
forward:(bool) If it is set to true (the default) request is forwarded to subgroups. Otherwise, it is only applied to the local set of devices.
multi:(bool) If it is set to false (the default), the same value is applied to all devices in the group. Otherwise the value is interpreted as a sequence of values, and each value is applied to the corresponding device in the group. In this case len(value) must be equal to group.get_size()!
Return:

(int) request id. Pass the returned request id to Group.write_attribute_reply() to obtain the acknowledgements.
Throws:
write_attribute_reply(self, req_id, timeout_ms=0) → sequence<GroupReply>
Returns the acknowledgements of an asynchronous attribute writing.
Parameters:
req_id:(int) a request identifier previously returned by write_attribute_asynch.
timeout_ms:(int) For each device in the hierarchy, if the acknowledgment is not yet available, write_attribute_reply wait timeout_ms milliseconds before throwing an exception. This exception will be part of the global reply. If timeout_ms is set to 0, write_attribute_reply waits “indefinitely”.
Return:

(sequence<GroupReply>)
Throws:

GroupReply classes

Group member functions do not return the same as their DeviceProxy counterparts, but objects that contain them. This is:

  • write attribute family returns PyTango.GroupReplyList
  • read attribute family returns PyTango.GroupAttrReplyList
  • command inout family returns PyTango.GroupCmdReplyList

The Group*ReplyList objects are just list-like objects containing GroupReply, GroupAttrReply and GroupCmdReply elements that will be described now.

Note also that GroupReply is the base of GroupCmdReply and GroupAttrReply.

class PyTango.GroupReply

This is the base class for the result of an operation on a PyTangoGroup, being it a write attribute, read attribute, or command inout operation.

It has some trivial common operations:

  • has_failed(self) -> bool
  • group_element_enabled(self) ->bool
  • dev_name(self) -> str
  • obj_name(self) -> str
  • get_err_stack(self) -> DevErrorList
class PyTango.GroupAttrReply

Bases: PyTango._PyTango.GroupReply

get_data(self, extract_as=ExtractAs.Numpy) → DeviceAttribute
Get the DeviceAttribute.
Parameters:
extract_as:(ExtractAs)
Return:

(DeviceAttribute) Whatever is stored there, or None.
class PyTango.GroupCmdReply

Bases: PyTango._PyTango.GroupReply

get_data(self) → any
Get the actual value stored in the GroupCmdRply, the command output value. It’s the same as self.get_data_raw().extract()
Parameters:None
Return:(any) Whatever is stored there, or None.
get_data_raw(self) → any
Get the DeviceData containing the output parameter of the command.
Parameters:None
Return:(DeviceData) Whatever is stored there, or None.