Miscellaneous

API util

class tango.ApiUtil

This class allows you to access the tango synchronization model API. It is designed as a singleton. To get a reference to the singleton object you must do:

import tango
api_util = tango.ApiUtil.instance()

Added in version 7.1.3.

static cleanup() → None

Destroy the ApiUtil singleton instance. After calling cleanup(), any existing DeviceProxy, AttributeProxy, or Database objects become invalid and must be reconstructed.

Added in version 9.3.0.

enable_event_system_perf_mon(self: tango._tango.ApiUtil, flag: bool) → None

Enables/disables event system performance counter for server supplier (if running) and proxy consumer in current process

See also query_event_system()

Parameters:

flag (bool) – new state of system performance counter

Added in version 10.3.0.

Warning

Enabled monitoring has a small performance penalty for the event system.

get_asynch_cb_sub_model(self: tango._tango.ApiUtil) → tango._tango.cb_sub_model

Get the asynchronous callback sub-model.

Added in version 7.1.3.

get_asynch_replies(*args, **kwargs)

Overloaded function.

1. get_asynch_replies(self: tango._tango.ApiUtil) -> None

Fire callback methods for all asynchronous requests (command and attribute) which already have arrived replies. Returns immediately if no replies arrived or there are no asynchronous requests.

Throws:

None, all errors are reported via the callback’s err/errors fields.

Added in version 7.1.3.

2. get_asynch_replies(self: tango._tango.ApiUtil, timeout: typing.SupportsInt | typing.SupportsIndex) -> None

Fire callback methods for all asynchronous requests (command and attributes) with already arrived replies. Wait up to timeout milliseconds if some replies haven’t arrived yet. If timeout=0, waits until all requests receive a reply.

Parameters:

timeout (int) – timeout in milliseconds

Throws:

AsynReplyNotArrived if some replies did not arrive in time. Other errors are reported via the callback’s err/errors fields.

Added in version 7.1.3.

static get_env_var(name: str) → object

Return the environment variable value for the given name.

Parameters:

name (str) – Environment variable name

get_ip_from_if(self: tango._tango.ApiUtil, interface_name: tango._tango.StdStringVector) → None

Get the IP address for the given network interface name.

Parameters:

interface_name (str) – The name of the network interface

get_user_connect_timeout(self: tango._tango.ApiUtil) → int

Get the user connect timeout (in milliseconds).

in_server(self: tango._tango.ApiUtil) → bool

Returns True if the current process is running a Tango device server.

Added in version 10.0.0.

static instance() → tango._tango.ApiUtil

Returns the ApiUtil singleton instance.

Added in version 7.1.3.

is_notifd_event_consumer_created(self: tango._tango.ApiUtil) → bool

Check if the notifd event consumer was created.

is_zmq_event_consumer_created(self: tango._tango.ApiUtil) → bool

Check if the ZMQ event consumer was created.

pending_asynch_call(self: tango._tango.ApiUtil, req: tango._tango.asyn_req_type) → int

Return the number of asynchronous pending requests (any device) for the given type. The input parameter is an enumeration with three values: - POLLING - CALL_BACK - ALL_ASYNCH

Parameters:

req (asyn_req_type) – asynchronous request type

Added in version 7.1.3.

query_event_system(self: tango._tango.ApiUtil) → str

Returns info about both sides of event system in current process: server supplier (if running) and proxy consumer

This feature is described in the cppTango docs: https://tango-controls.gitlab.io/cppTango/10.1.0/query_event_system.html

See also enable_event_system_perf_mon()

Returns:

Json dump of event system info

Added in version 10.3.0.

set_asynch_cb_sub_model(self: tango._tango.ApiUtil, model: tango._tango.cb_sub_model) → None

Set the asynchronous callback sub-model between PULL_CALLBACK or PUSH_CALLBACK.

Parameters:

model (cb_sub_model) – the callback sub-model

Added in version 7.1.3.

Information classes

See also [Event configuration information]

Attribute

class tango.AttributeAlarmInfo

A structure containing available alarm information for an attribute with the following members:

• min_alarm : (str) low alarm level

• max_alarm : (str) high alarm level

• min_warning : (str) low warning level

• max_warning : (str) high warning level

• delta_t : (str) time delta

• delta_val : (str) value delta

• extensions : (list[str]) extensions (currently not used)

class tango.AttributeDimension

A structure containing x and y attribute data dimensions with the following members:

• dim_x : (int) x dimension

• dim_y : (int) y dimension

class tango.AttributeInfo

A structure (inheriting from DeviceAttributeConfig) containing available information for an attribute with the following members:

• disp_level : (DispLevel) display level (OPERATOR, EXPERT)

Inherited members are:

• name : (str) attribute name

• writable : (AttrWriteType) write type (R, W, RW, R with W)

• data_format : (AttrDataFormat) data format (SCALAR, SPECTRUM, IMAGE)

• data_type : (int) attribute type (float, string,..)

• max_dim_x : (int) first dimension of attribute (spectrum or image attributes)

• max_dim_y : (int) second dimension of attribute(image attribute)

• description : (int) attribute description

• label : (str) attribute label (Voltage, time, …)

• unit : (str) attribute unit (V, ms, …)

• standard_unit : (str) standard unit

• display_unit : (str) display unit

• format : (str) how to display the attribute value (ex: for floats could be ‘%6.2f’)

• min_value : (str) minimum allowed value

• max_value : (str) maximum allowed value

• min_alarm : (str) low alarm level

• max_alarm : (str) high alarm level

• writable_attr_name : (str) name of the writable attribute

• extensions : (list[str]) extensions (currently not used)

class tango.AttributeInfoEx

A structure (inheriting from AttributeInfo) containing available information for an attribute with the following members:

• alarms : object containing alarm information (see AttributeAlarmInfo).

• events : object containing event information (see AttributeEventInfo).

• sys_extensions : list[str]

Inherited members are:

• name : (str) attribute name

• writable : (AttrWriteType) write type (R, W, RW, R with W)

• data_format : (AttrDataFormat) data format (SCALAR, SPECTRUM, IMAGE)

• data_type : (int) attribute type (float, string,..)

• max_dim_x : (int) first dimension of attribute (spectrum or image attributes)

• max_dim_y : (int) second dimension of attribute(image attribute)

• description : (int) attribute description

• label : (str) attribute label (Voltage, time, …)

• unit : (str) attribute unit (V, ms, …)

• standard_unit : (str) standard unit

• display_unit : (str) display unit

• format : (str) how to display the attribute value (ex: for floats could be ‘%6.2f’)

• min_value : (str) minimum allowed value

• max_value : (str) maximum allowed value

• min_alarm : (str) low alarm level

• max_alarm : (str) high alarm level

• writable_attr_name : (str) name of the writable attribute

• extensions : (list[str]) extensions (currently not used)

• disp_level : (DispLevel) display level (OPERATOR, EXPERT)

see also AttributeInfo

class tango.DeviceAttributeConfig

A base structure containing available information for an attribute with the following members:

• name : (str) attribute name

• writable : (AttrWriteType) write type (R, W, RW, R with W)

• data_format : (AttrDataFormat) data format (SCALAR, SPECTRUM, IMAGE)

• data_type : (int) attribute type (float, string,..)

• max_dim_x : (int) first dimension of attribute (spectrum or image attributes)

• max_dim_y : (int) second dimension of attribute(image attribute)

• description : (int) attribute description

• label : (str) attribute label (Voltage, time, …)

• unit : (str) attribute unit (V, ms, …)

• standard_unit : (str) standard unit

• display_unit : (str) display unit

• format : (str) how to display the attribute value (ex: for floats could be ‘%6.2f’)

• min_value : (str) minimum allowed value

• max_value : (str) maximum allowed value

• min_alarm : (str) low alarm level

• max_alarm : (str) high alarm level

• writable_attr_name : (str) name of the writable attribute

• extensions : (list[str]) extensions (currently not used)

Command

class tango.DevCommandInfo

A device command info with the following members:

• cmd_name : (str) command name

• cmd_tag : command as binary value (for TACO)

• in_type : (CmdArgType) input type

• out_type : (CmdArgType) output type

• in_type_desc : (str) description of input type

• out_type_desc : (str) description of output type

Added in version 7.0.0.

class tango.CommandInfo

A device command info (inheriting from DevCommandInfo) with the following members:

• disp_level : (DispLevel) command display level

Inherited members are (from DevCommandInfo):

• cmd_name : (str) command name

• cmd_tag : (str) command as binary value (for TACO)

• in_type : (CmdArgType) input type

• out_type : (CmdArgType) output type

• in_type_desc : (str) description of input type

• out_type_desc : (str) description of output type

Other

class tango.DeviceInfo

A structure containing available information for a device with the following members:

• dev_class : (str) device class

• server_id : (str) server ID

• server_host : (str) host name

• server_version : (str) server version

• doc_url : (str) document url

• version_info : (dict[str, str]) version info dict

Changed in version 10.0.0: Added version_info field

class tango.LockerInfo

A structure with information about the locker with the following members:

• ll : (tango.LockerLanguage) the locker language

• li : (pid_t / UUID) the locker id: pid_t should be an int, UUID should be a tuple of four numbers.

• locker_host : (str) the host

• locker_class : (str) the class

Added in version 7.0.0.

class tango.PollDevice

A structure containing PollDevice information with the following members:

• dev_name : (str) device name

• ind_list : (list[int]) index list

Added in version 7.0.0.

Storage classes

Attribute: DeviceAttribute

class tango.DeviceAttribute(da=None)

This is the fundamental type for RECEIVING data from device attributes.

It contains several fields. The most important ones depend on the ExtractAs method used to get the value. Normally they are:

• value : Normal scalar value or numpy array of values.

• w_value : The write part of the attribute.

See other ExtractAs for different possibilities. There are some more fields, these really fixed:

• name : (str)

• data_format : (AttrDataFormat) Attribute format

• quality : (AttrQuality)

• time : (TimeVal)

• dim_x : (int) attribute dimension x

• dim_y : (int) attribute dimension y

• w_dim_x : (int) attribute written dimension x

• w_dim_y : (int) attribute written dimension y

• r_dimension : (tuple[int,int]) Attribute read dimensions.

• w_dimension : (tuple[int,int]) Attribute written dimensions.

• nb_read : (int) attribute read total length

• nb_written : (int) attribute written total length

And two methods:

• get_date

• get_err_stack

class ExtractAs(*values)

Defines what will go into value field of DeviceAttribute, or what will Attribute.get_write_value() return. Not all the possible values are valid in all the cases

List = 4

Numpy = 0

String = 5

Tuple = 3

class except_flags(*values)

get_date(self: tango._tango.DeviceAttribute) → tango._tango.TimeVal

Get the time at which the attribute was read by the server.

Note: It’s the same as reading the “time” attribute.

get_err_stack(self: tango._tango.DeviceAttribute) → list[DevError]

Returns the error stack reported by the server when the attribute was read.

set_w_dim_x(self: tango._tango.DeviceAttribute, val: SupportsInt | SupportsIndex) → None

Sets the write value dim x.

Parameters:

val (int) – new write dim x

Added in version 8.0.0.

set_w_dim_y(self: tango._tango.DeviceAttribute, val: SupportsInt | SupportsIndex) → None

Sets the write value dim y.

Parameters:

val (int) – new write dim y

Added in version 8.0.0.

Command: DeviceData

Device data is the type used internally by Tango to deal with command parameters and return values. You don’t usually need to deal with it, as command_inout will automatically convert the parameters from any other type and the result value to another type.

You can still use them, using command_inout_raw to get the result in a DeviceData.

You also may deal with it when reading command history.

class tango.DeviceData

This is the fundamental type for sending and receiving data from device commands. The values can be inserted and extracted using the insert() and extract() methods.

class except_flags(*values)

extract(self: object, extract_as: tango._tango.ExtractAs = ExtractAs.Numpy) → object

Get the actual value stored in the DeviceData.

Return type:

typing.Any

get_type(self: tango._tango.DeviceData) → tango._tango.CmdArgType

This method returns the Tango data type of the data inside the DeviceData object

insert(self: tango._tango.DeviceData, data_type: SupportsInt | SupportsIndex, value: object) → None

Inserts a value in the DeviceData.

Parameters:

• data_type (int)

• value (typing.Any) – The value to insert

is_empty(self: tango._tango.DeviceData) → bool

It can be used to test whether the DeviceData object has been initialized or not.

Callback related classes

If you subscribe a callback in a DeviceProxy, it will be run with a parameter. This parameter depends will be of one of the following classes depending on the callback type.

class tango.AttrReadEvent

property argout

(DeviceAttribute) The attribute value

property attr_names

(list[str]) The attribute name list

property device

(DeviceProxy) The DeviceProxy object on which the call was executed

property err

(bool) A boolean flag set to true if the command failed. False otherwise

property errors

(list[DevError]) The error stack

class tango.AttrWrittenEvent

property attr_names

(list[str]) The attribute name list

property device

(DeviceProxy) The DeviceProxy object on which the call was executed

property err

(bool) A boolean flag set to true if the command failed. False otherwise

property errors

(list[DevError]) The error stack

class tango.CmdDoneEvent

This class is used to pass data to the callback method in asynchronous callback model for command execution.

property argout

(typing.Any) The command argout

property cmd_name

(list[str]) The command name list

property device

(DeviceProxy) The DeviceProxy object on which the call was executed.

property err

(bool) A boolean flag set to true if the command failed. False otherwise

property errors

(list[DevError]) The error stack

Event related classes

Event configuration information

class tango.AttributeEventInfo

A structure containing available event information for an attribute with the following members:

• ch_event : (ChangeEventInfo) change event information

• per_event : (PeriodicEventInfo) periodic event information

• arch_event : (ArchiveEventInfo) archiving event information

class tango.ArchiveEventInfo

A structure containing available archiving event information for an attribute with the following members:

• archive_rel_change : (str) relative change that will generate an event

• archive_abs_change : (str) absolute change that will generate an event

• archive_period : (str) archive period

• extensions : (list[str]) extensions (currently not used)

class tango.ChangeEventInfo

A structure containing available change event information for an attribute with the following members:

• rel_change : (str) relative change that will generate an event

• abs_change : (str) absolute change that will generate an event

• extensions : (list[str]) extensions (currently not used)

class tango.PeriodicEventInfo

A structure containing available periodic event information for an attribute with the following members:

• period : (str) event period

• extensions : (list[str]) extensions (currently not used)

Event subscription structures

class tango.EventSubMode(*values)

An enumeration representing the sub mode used when subscribing to events.

• EventSubMode.SyncRead - synchronous subscription including attribute read (raises exception on failure), first callback immediately with current value.

• EventSubMode.AsyncRead - asynchronous subscription and asynchronous attribute read (no exception on failure, retries automatically), first callback “soon” after read with current value.

• EventSubMode.Sync - synchronous subscription without reading attribute (raises exception on failure), no callback on subscription (only on next event).

• EventSubMode.Async - asynchronous subscription without reading attribute (no exception on failure, retries automatically), first callback with no value when subscription completed.

• EventSubMode.Stateless - synchronous subscription including attribute read (no exception on failure, retries automatically) - equivalent to old stateless=True option, first callback immediately with current value. Consider AsyncRead instead.

The table below summarises this:

Event Subscription Modes

EventSubMode	Tries subscription before returning	Raises on subscription failure	Reads entity	First callback
SyncRead	Yes	Yes	Yes, during subscription	Immediately, with data
AsyncRead	No	No	Yes, after subscription	After read, with data
Sync	Yes	Yes	No	Only on next event
Async	No	No	No	After subscription, no data
Stateless	Yes	No	Yes, during subscription	Immediately, with data

See tango.DeviceProxy.subscribe_event().

Added in version 10.1.0.

Event arrived structures

class tango.EventData

This class is used to pass data to the callback method when an event related to attribute data is sent to the client. It contains the following public fields:

• device : (DeviceProxy) The DeviceProxy object on which the call was executed.

• attr_name : (str) The attribute name

• event : (str) The event type name

• event_reason : (EventReason) The reason for the event

• attr_value : (DeviceAttribute) The attribute data

• err : (bool) A boolean flag set to true if the request failed. False otherwise

• errors : (list[DevError]) The error stack

• reception_date: (TimeVal)

Note

The attr_value field may be None. E.g., if err is True, or when subscribing in EventSubMode.Async mode and the initial callback is received with EventReason.SubSuccess.

get_date(self: tango._tango.EventData) → tango._tango.TimeVal

Returns the timestamp of the event.

Added in version 7.0.0.

class tango.AttrConfEventData

This class is used to pass data to the callback method when an attribute configuration event (tango.EventType.ATTR_CONF_EVENT) is sent to the client. It contains the following public fields:

• device : (DeviceProxy) The DeviceProxy object on which the call was executed

• attr_name : (str) The attribute name

• event : (str) The event type name

• event_reason : (EventReason) The reason for the event

• attr_conf : (AttributeInfoEx) The attribute data

• err : (bool) A boolean flag set to true if the request failed. False otherwise

• errors : (list[DevError]) The error stack

• reception_date: (TimeVal)

get_date(self: tango._tango.AttrConfEventData) → tango._tango.TimeVal

Returns the timestamp of the event.

Added in version 7.0.0.

class tango.DataReadyEventData

This class is used to pass data to the callback method when an attribute data ready event (tango.EventType.DATA_READY_EVENT) is sent to the client. It contains the following public fields:

• device : (DeviceProxy) The DeviceProxy object on which the call was executed

• attr_name : (str) The attribute name

• event : (str) The event type name

• event_reason : (EventReason) The reason for the event

• attr_data_type : (int) The attribute data type

• ctr : (int) The user counter. Set to 0 if not defined when sent by the server

• err : (bool) A boolean flag set to true if the request failed. False otherwise

• errors : (list[DevError]) The error stack

• reception_date: (TimeVal)

Added in version 7.0.0.

get_date(self: tango._tango.DataReadyEventData) → tango._tango.TimeVal

Returns the timestamp of the event.

class tango.DevIntrChangeEventData

This class is used to pass data to the callback method when a device interface changed event (tango.EventType.INTERFACE_CHANGE_EVENT) is sent to the client. It contains the following public fields:

• device : (DeviceProxy) The DeviceProxy object on which the call was executed

• event : (str) The event type name

• event_reason : (EventReason) The reason for the event

• device_name : (str) Tango device name

• dev_started : (bool) True when event sent due to device being (re)started and with only a possible, but not certain, interface change

• att_list : (AttributeInfoListEx) List of attribute details (only available in callback)

• cmd_list : (CommandInfoList) List of command details (only available in callback)

• err : (bool) A boolean flag set to true if the request failed. False otherwise

• errors : (list[DevError]) The error stack

• reception_date: (TimeVal)

get_date(self: tango._tango.DevIntrChangeEventData) → tango._tango.TimeVal

Returns the timestamp of the event.

class tango.EventReason(*values)

An enumeration representing the reason for an event.

• EventReason.SubSuccess - initial subscription was successful. Note: Event data will not have a value for EventSubMode.Async subscription. Not emitted for EventSubMode.Sync.

• EventReason.Update - new event available. Device has pushed a new event, or re-subscription after loosing connection to device (e.g., after restart).

• EventReason.SubFail - initial asynchronous subscription failed, or event system down (“Event channel is not responding anymore”).

• EventReason.Unknown - unexpected - probably a bug in cppTango or PyTango.

See tango.EventSubMode.

Added in version 10.1.0.

History classes

class tango.DeviceAttributeHistory

Bases: DeviceAttribute

has_failed(self: tango._tango.DeviceAttributeHistory) → bool

See DeviceAttribute.

class tango.DeviceDataHistory

Bases: DeviceData

get_date(self: tango._tango.DeviceDataHistory) → tango._tango.TimeVal

Get date when the device server polling thread has executed the command

get_err_stack(self: tango._tango.DeviceDataHistory) → list[DevError]

Get record error stack recorded by the device server polling thread in case of the command failed when it was invoked

has_failed(self: tango._tango.DeviceDataHistory) → bool

Check if the record in the polling buffer was a failure

See DeviceData.