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|
```{eval-rst}
.. currentmodule:: tango.server
```
(pytango-hlapi)=
# High level server API
```{eval-rst}
.. automodule:: tango.server
```
```{eval-rst}
.. hlist::
* :class:`~tango.server.Device`
* :class:`~tango.server.attribute`
* :class:`~tango.server.command`
* :class:`~tango.server.pipe`
* :class:`~tango.server.device_property`
* :class:`~tango.server.class_property`
* :func:`~tango.server.run`
* :func:`~tango.server.server_run`
```
This module provides a high level device server API. It implements
[TEP1](#pytango-TEP1). It exposes an easier API for developing a Tango
device server.
Here is a simple example on how to write a *Clock* device server using the
high level API:
```
import time
from tango.server import run
from tango.server import Device
from tango.server import attribute, command
class Clock(Device):
time = attribute()
def read_time(self):
return time.time()
@command(dtype_in=str, dtype_out=str)
def strftime(self, format):
return time.strftime(format)
if __name__ == "__main__":
run((Clock,))
```
Here is a more complete example on how to write a *PowerSupply* device server
using the high level API. The example contains:
1. device description (via docstring), which user can get later as DeviceProxy.description()
2. default state DevState.ON and default status "Device is current supply mode"
3. a read-only double scalar attribute called *voltage*
4. a read/write double scalar expert attribute *current*
5. a read-only double image attribute called *noise*
6. a *ramp* command
7. a *host* device property
8. a *port* class property
```{code-block} python
:linenos: true
from time import time
from numpy.random import random_sample
from tango import AttrQuality, AttrWriteType, DevState, DispLevel
from tango.server import Device, attribute, command
from tango.server import class_property, device_property
class PowerSupply(Device):
"""PyTango example of PowerSuppy device."""
# alternative way to add device description (see note below)
DEVICE_CLASS_DESCRIPTION = "PyTango example of PowerSuppy device."
DEVICE_CLASS_INITIAL_STATUS = "Device is in current supply mode"
DEVICE_CLASS_INITIAL_STATE = DevState.ON
voltage = attribute()
current = attribute(label="Current", dtype=float,
display_level=DispLevel.EXPERT,
access=AttrWriteType.READ_WRITE,
unit="A", format="8.4f",
min_value=0.0, max_value=8.5,
min_alarm=0.1, max_alarm=8.4,
min_warning=0.5, max_warning=8.0,
fget="get_current", fset="set_current",
doc="the power supply current")
noise = attribute(label="Noise", dtype=((float,),),
max_dim_x=1024, max_dim_y=1024,
fget="get_noise")
host = device_property(dtype=str)
port = class_property(dtype=int, default_value=9788)
def read_voltage(self):
self.info_stream(f"Get voltage({self.host}, {self.port})")
return 10.0
def get_current(self):
return 2.3456, time(), AttrQuality.ATTR_CHANGING
def set_current(self, current):
self.info_stream(f"Current set to {current}")
def get_noise(self):
return random_sample((1024, 1024))
@command(dtype_in=float)
def ramp(self, value):
self.info_stream(f"Ramp up requested: {value} seconds")
if __name__ == "__main__":
PowerSupply.run_server()
```
*Pretty cool, uh?*
:::{note}
the device description can be added either by class docstring or by DEVICE_CLASS_DESCRIPTION class member, the latter has priority over the docstring.
The important difference is that DEVICE_CLASS_DESCRIPTION will be inherited by child classes, while the docstring will not be.
:::
(pytango-hlapi-datatypes)=
```{rubric} Data types
```
When declaring attributes, properties or commands, one of the most important
details is the data type. It is given by the keyword argument *dtype*.
In order to provide a more *pythonic* interface, this argument is not restricted
to the {obj}`~tango.CmdArgType` options.
For example, to define a *SCALAR* {obj}`~tango.CmdArgType.DevLong`
attribute you have several possibilities:
1. {obj}`int`
2. 'int'
3. 'int64'
4. {obj}`tango.CmdArgType.DevLong64`
5. 'DevLong64'
6. {obj}`numpy.int64`
To define a *SPECTRUM* attribute simply wrap the scalar data type in any
python sequence:
- using a *tuple*: `` (:obj:`int`,) `` or
- using a *list*: `` [:obj:`int`] `` or
- any other sequence type
To define an *IMAGE* attribute simply wrap the scalar data type in any
python sequence of sequences:
- using a *tuple*: `` ((:obj:`int`,),) `` or
- using a *list*: `` [[:obj:`int`]] `` or
- any other sequence type
Below is the complete table of equivalences.
| dtype argument | converts to tango type |
| --------------------------- | ------------------------- |
| `None` | `DevVoid` |
| `'None'` | `DevVoid` |
| `DevVoid` | `DevVoid` |
| `'DevVoid'` | `DevVoid` |
| `DevState` | `DevState` |
| `'DevState'` | `DevState` |
| {py:obj}`bool` | `DevBoolean` |
| `'bool'` | `DevBoolean` |
| `'boolean'` | `DevBoolean` |
| `DevBoolean` | `DevBoolean` |
| `'DevBoolean'` | `DevBoolean` |
| {py:obj}`numpy.bool_` | `DevBoolean` |
| `'char'` | `DevUChar` |
| `'chr'` | `DevUChar` |
| `'byte'` | `DevUChar` |
| `chr` | `DevUChar` |
| `DevUChar` | `DevUChar` |
| `'DevUChar'` | `DevUChar` |
| {py:obj}`numpy.uint8` | `DevUChar` |
| `'int16'` | `DevShort` |
| `DevShort` | `DevShort` |
| `'DevShort'` | `DevShort` |
| {py:obj}`numpy.int16` | `DevShort` |
| `'uint16'` | `DevUShort` |
| `DevUShort` | `DevUShort` |
| `'DevUShort'` | `DevUShort` |
| {py:obj}`numpy.uint16` | `DevUShort` |
| `'int32'` | `DevLong` |
| `DevLong` | `DevLong` |
| `'DevLong'` | `DevLong` |
| {py:obj}`numpy.int32` | `DevLong` |
| `'uint32'` | `DevULong` |
| `DevULong` | `DevULong` |
| `'DevULong'` | `DevULong` |
| {py:obj}`numpy.uint32` | `DevULong` |
| {py:obj}`int` | `DevLong64` |
| `'int'` | `DevLong64` |
| `'int64'` | `DevLong64` |
| `DevLong64` | `DevLong64` |
| `'DevLong64'` | `DevLong64` |
| {py:obj}`numpy.int64` | `DevLong64` |
| `'uint'` | `DevULong64` |
| `'uint64'` | `DevULong64` |
| `DevULong64` | `DevULong64` |
| `'DevULong64'` | `DevULong64` |
| {py:obj}`numpy.uint64` | `DevULong64` |
| `'float32'` | `DevFloat` |
| `DevFloat` | `DevFloat` |
| `'DevFloat'` | `DevFloat` |
| {py:obj}`numpy.float32` | `DevFloat` |
| {py:obj}`float` | `DevDouble` |
| `'double'` | `DevDouble` |
| `'float'` | `DevDouble` |
| `'float64'` | `DevDouble` |
| `DevDouble` | `DevDouble` |
| `'DevDouble'` | `DevDouble` |
| {py:obj}`numpy.float64` | `DevDouble` |
| {py:obj}`str` | `DevString` |
| `'str'` | `DevString` |
| `'string'` | `DevString` |
| `'text'` | `DevString` |
| `DevString` | `DevString` |
| `'DevString'` | `DevString` |
| {py:obj}`bytearray` | `DevEncoded` |
| `'bytearray'` | `DevEncoded` |
| `'bytes'` | `DevEncoded` |
| `DevEncoded` | `DevEncoded` |
| `'DevEncoded'` | `DevEncoded` |
| `DevVarBooleanArray` | `DevVarBooleanArray` |
| `'DevVarBooleanArray'` | `DevVarBooleanArray` |
| `DevVarCharArray` | `DevVarCharArray` |
| `'DevVarCharArray'` | `DevVarCharArray` |
| `DevVarShortArray` | `DevVarShortArray` |
| `'DevVarShortArray'` | `DevVarShortArray` |
| `DevVarLongArray` | `DevVarLongArray` |
| `'DevVarLongArray'` | `DevVarLongArray` |
| `DevVarLong64Array` | `DevVarLong64Array` |
| `'DevVarLong64Array'` | `DevVarLong64Array` |
| `DevVarULong64Array` | `DevVarULong64Array` |
| `'DevVarULong64Array'` | `DevVarULong64Array` |
| `DevVarFloatArray` | `DevVarFloatArray` |
| `'DevVarFloatArray'` | `DevVarFloatArray` |
| `DevVarDoubleArray` | `DevVarDoubleArray` |
| `'DevVarDoubleArray'` | `DevVarDoubleArray` |
| `DevVarUShortArray` | `DevVarUShortArray` |
| `'DevVarUShortArray'` | `DevVarUShortArray` |
| `DevVarULongArray` | `DevVarULongArray` |
| `'DevVarULongArray'` | `DevVarULongArray` |
| `DevVarStringArray` | `DevVarStringArray` |
| `'DevVarStringArray'` | `DevVarStringArray` |
| `DevVarLongStringArray` | `DevVarLongStringArray` |
| `'DevVarLongStringArray'` | `DevVarLongStringArray` |
| `DevVarDoubleStringArray` | `DevVarDoubleStringArray` |
| `'DevVarDoubleStringArray'` | `DevVarDoubleStringArray` |
| `DevPipeBlob` | `DevPipeBlob` |
| `'DevPipeBlob'` | `DevPipeBlob` |
```{eval-rst}
.. autoclass:: Device
:show-inheritance:
:inherited-members:
:members:
```
```{eval-rst}
.. autoclass:: attribute
```
```{eval-rst}
.. autofunction:: command
```
```{eval-rst}
.. autoclass:: pipe
```
```{eval-rst}
.. autoclass:: device_property
```
```{eval-rst}
.. autoclass:: class_property
```
```{eval-rst}
.. autofunction:: run
```
```{eval-rst}
.. autofunction:: server_run
```
|
