def test_setattr_expression_index():
class A(object):
x = ['x', 'y', 'z']
a = A()
setattr_expression(a, 'x[1]', 'foo')
assert a.x[1] == 'foo'
def test_setattr_expression_simple():
class A(object):
x = 'x'
y = 'y'
z = 'z'
a = A()
setattr_expression(a, 'x', 'foo')
assert a.x == 'foo'
def test_setattr_expression_both():
class B(object):
x = 'x'
class A(object):
b = None
def __init__(self):
self.b = [B()]
a = A()
setattr_expression(a, 'b[0].x', 'foo')
assert a.b[0].x == 'foo'
def test_setattr_expression_nested():
class B(object):
x = 'x'
class A(object):
b = None
def __init__(self):
self.b = B()
a = A()
setattr_expression(a, 'b.x', 'foo')
assert a.b.x == 'foo'
def load_instruments(conf_file_name, conf_path="/"):
"""
Given the path to a YAML-formatted configuration file and a path within
that file, loads the instruments described in that configuration file.
The subsection of the configuration file is expected to look like a map from
names to YAML nodes giving the class and instrument URI for each instrument.
For example::
ddg:
class: !!python/name:instruments.srs.SRSDG645
uri: gpib+usb://COM7/15
Loading instruments from this configuration will result in a dictionary of
the form
``{'ddg': instruments.srs.SRSDG645.open_from_uri('gpib+usb://COM7/15')}``.
Each instrument configuration section can also specify one or more attributes
to set. These attributes are specified using a ``attrs`` section as well as the
required ``class`` and ``uri`` sections. For instance, the following
dictionary creates a ThorLabs APT motor controller instrument with a single motor
model configured::
rot_stage:
class: !!python/name:instruments.thorabsapt.APTMotorController
uri: serial:///dev/ttyUSB0?baud=115200
attrs:
channel[0].motor_model: PRM1-Z8
Unitful attributes can be specified by using the ``!Q`` tag to quickly create
instances of `pq.Quantity`. In the example above, for instance, we can set a motion
timeout as a unitful quantity::
attrs:
motion_timeout: !Q 1 minute
When using the ``!Q`` tag, any text before a space is taken to be the magnitude
of the quantity, and text following is taken to be the unit specification.
By specifying a path within the configuration file, one can load only a part
of the given file. For instance, consider the configuration::
instruments:
ddg:
class: !!python/name:instruments.srs.SRSDG645
uri: gpib+usb://COM7/15
prefs:
...
Then, specifying ``"/instruments"`` as the configuration path will cause
this function to load the instruments named in that block, and ignore
all other keys in the YAML file.
:param str conf_file_name: Name of the configuration file to load
instruments from. Alternatively, a file-like object may be provided.
:param str conf_path: ``"/"`` separated path to the section in the
configuration file to load.
:rtype: `dict`
.. warning::
The configuration file must be trusted, as the class name references
allow for executing arbitrary code. Do not load instruments from
configuration files sent over network connections.
Note that keys in sections excluded by the ``conf_path`` argument are
still processed, such that any side effects that may occur due to
such processing will occur independently of the value of ``conf_path``.
"""
if yaml is None:
raise ImportError("Could not import ruamel.yaml, which is required "
"for this function.")
if isinstance(conf_file_name, str):
with open(conf_file_name, 'r') as f:
conf_dict = yaml.load(f, Loader=yaml.Loader)
else:
conf_dict = yaml.load(conf_file_name, Loader=yaml.Loader)
conf_dict = walk_dict(conf_dict, conf_path)
inst_dict = {}
for name, value in conf_dict.items():
try:
inst_dict[name] = value["class"].open_from_uri(value["uri"])
if 'attrs' in value:
# We have some attrs we can set on the newly created instrument.
for attr_name, attr_value in value['attrs'].items():
setattr_expression(inst_dict[name], attr_name, attr_value)
except IOError as ex:
# FIXME: need to subclass Warning so that repeated warnings
# aren't ignored.
warnings.warn("Exception occured loading device with URI "
"{}:\n\t{}.".format(value["uri"], ex), RuntimeWarning)
inst_dict[name] = None
return inst_dict
def load_instruments(conf_file_name, conf_path="/"):
"""
Given the path to a YAML-formatted configuration file and a path within
that file, loads the instruments described in that configuration file.
The subsection of the configuration file is expected to look like a map from
names to YAML nodes giving the class and instrument URI for each instrument.
For example::
ddg:
class: !!python/name:instruments.srs.SRSDG645
uri: gpib+usb://COM7/15
Loading instruments from this configuration will result in a dictionary of
the form
``{'ddg': instruments.srs.SRSDG645.open_from_uri('gpib+usb://COM7/15')}``.
Each instrument configuration section can also specify one or more attributes
to set. These attributes are specified using a ``attrs`` section as well as the
required ``class`` and ``uri`` sections. For instance, the following
dictionary creates a ThorLabs APT motor controller instrument with a single motor
model configured::
rot_stage:
class: !!python/name:instruments.thorabsapt.APTMotorController
uri: serial:///dev/ttyUSB0?baud=115200
attrs:
channel[0].motor_model: PRM1-Z8
Unitful attributes can be specified by using the ``!Q`` tag to quickly create
instances of `pq.Quantity`. In the example above, for instance, we can set a motion
timeout as a unitful quantity::
attrs:
motion_timeout: !Q 1 minute
When using the ``!Q`` tag, any text before a space is taken to be the magnitude
of the quantity, and text following is taken to be the unit specification.
By specifying a path within the configuration file, one can load only a part
of the given file. For instance, consider the configuration::
instruments:
ddg:
class: !!python/name:instruments.srs.SRSDG645
uri: gpib+usb://COM7/15
prefs:
...
Then, specifying ``"/instruments"`` as the configuration path will cause
this function to load the instruments named in that block, and ignore
all other keys in the YAML file.
:param str conf_file_name: Name of the configuration file to load
instruments from. Alternatively, a file-like object may be provided.
:param str conf_path: ``"/"`` separated path to the section in the
configuration file to load.
:rtype: `dict`
.. warning::
The configuration file must be trusted, as the class name references
allow for executing arbitrary code. Do not load instruments from
configuration files sent over network connections.
Note that keys in sections excluded by the ``conf_path`` argument are
still processed, such that any side effects that may occur due to
such processing will occur independently of the value of ``conf_path``.
"""
if yaml is None:
raise ImportError("Could not import ruamel.yaml, which is required "
"for this function.")
if isinstance(conf_file_name, str):
with open(conf_file_name, 'r') as f:
conf_dict = yaml.load(f, Loader=yaml.Loader)
else:
conf_dict = yaml.load(conf_file_name, Loader=yaml.Loader)
conf_dict = walk_dict(conf_dict, conf_path)
inst_dict = {}
for name, value in conf_dict.items():
try:
inst_dict[name] = value["class"].open_from_uri(value["uri"])
if 'attrs' in value:
# We have some attrs we can set on the newly created instrument.
for attr_name, attr_value in value['attrs'].items():
setattr_expression(inst_dict[name], attr_name, attr_value)
except IOError as ex:
# FIXME: need to subclass Warning so that repeated warnings
# aren't ignored.
warnings.warn(
"Exception occured loading device with URI "
"{}:\n\t{}.".format(value["uri"], ex), RuntimeWarning)
inst_dict[name] = None
return inst_dict