I have the following class:
class MessageContext:
def __init__(self, raw_packet, packet_header, message_header, message_index):
self.raw_packet = raw_packet
self.pkthdr = packet_header
self.msghdr = message_header
self.msgidx = message_index
self.msg_seqno = packet_header.seqno + message_index
And a function that creates objects using the above class:
def parsers(data):
...
context = MessageContext(None, PacketAdapter(), msghdr, 0)
self.on_message(rawmsg, context)
I am trying to recreate context, and when i set a breakpoint just after it and print context, I get:
<exchanges.protocols.blahblah.MessageContext object at 0x7337211520>
I have left out quite a bit of code as it is very long, but if any more information is needed I am happy to provide of course.
Here is what I get when I print the arguments of MessageContext:
print(PacketAdapter()) -> <exchanges.blahblah.PacketAdapter object at 0x7f60929e1820>
Following the comments below, the PacketAdapter() class looks like this:
class PacketAdapter:
def __init__(self):
self.seqno = 0
First time poster and python newbie here, this question is probably asked before, but I am not able to find any answer.
I have a Class that reads robot status data, this works fine and I am able to dive my data into methods that are working fine when i call them. But I would like to divide my class even more, so the data is structured better. for example
I have some methods the reads and return target_data
def target_joint_positions(self):
t_j_p = self.read_data()[1:7]
return t_j_p
def target_joint_velocities(self):
t_j_v = self.read_data()[7:13]
return t_j_v
def target_joint_currents(self):
t_j_c = self.read_data()[19:25]
return t_j_c
And similar methods returning actual_data:
def actual_joint_positions(self):
a_j_p = self.read_data()[31:37]
return a_j_p
def actual_joint_velocities(self):
a_j_v = self.read_data()[37:43]
return a_j_v
def actual_joint_currents(self):
a_j_c = self.read_data()[43:49]
return a_j_c
So what I would like to accomplish is that when i make a instance of my class, instead of getting all the methods i would like something like this:
inst = Class_Name()
inst.target. (list of target methods)
inst.actual. (list of actual methods)
I have looked into nested classes and inheritance but I have not been successful in achieving my goal. Thanks for any pointers.
Welcome!
You can do the following:
class TargetMetrics:
def __init__(self, data):
self.data = data
def joint_positions(self):
return self.data[1:7]
...
class ActualMetrics:
def __init__(self, data):
self.data = data
def joint_positions(self):
return self.data[31:37]
...
class RobotMetrics:
def __init__(self):
data = read_data()
self.actual = ActualMetrics(data)
self.target = TargetMetrics(data)
...
There's a situation where I want to check how many times an internal class method has been called. I have a sensitive cloud task that must be done in a count that depends upon some circunstances. I would like to strengthen my application with an unittest to assert the number of times a specific function has been called.
To do so in a much simpler scenario, I would like to make a test in the following script:
class HMT:
def __init__(self):
self.buildedList = []
def handle(self, string_to_explode: str):
for exploded_part in string_to_explode.split(","):
self.doCoolThings(exploded_part)
def doCoolThings(self, fetched_raw_string: str):
self.buildedList.append("Cool thing done: " + fetched_raw_string)
Depending on the string that I deliver to the handle function, the doCoolThings will be called N times (in this simple case, depends solely in the number of comas inside the string).
I can make a test works by just counting the number of resulting elements inside builderList:
import unittest
from HMT import HMT
class test_HMT(unittest.TestCase):
def setUp(self):
self.hmt = HMT()
def test_hmt_3(self):
string_to_test = "alpha,beta,gamma"
self.hmt.handle(string_to_test)
self.assertEqual(3, len(self.hmt.buildedList))
def test_hmt_2(self):
string_to_test = "delta,epsilon"
self.hmt.handle(string_to_test)
self.assertEqual(2, len(self.hmt.buildedList))
But in the real scenario, there's will not have an available public class list that always will match its number of elements to the times the function doCoolThings was called.
So, how do I check how many times the doCoolThings was called without needing to check the list elements count?
I know that I can just put a counter in the class that is increased each time doCoolThings is called and expose it externally to be checked afterwards. But I don't would like to mess up the code putting lines that is not directly related to my business rule.
After #jarmod comment, I came into this code's version:
def mydecorator(func):
def wrapped(*args, **kwargs):
wrapped.calls += 1
return func(*args, **kwargs)
wrapped.calls = 0
return wrapped
class HMT:
def __init__(self):
self.buildedList = []
def handle(self, string_to_explode: str):
for exploded_part in string_to_explode.split(","):
self.doCoolThings(exploded_part)
#mydecorator
def doCoolThings(self, fetched_raw_string: str, *args, **kwargs):
self.buildedList.append("Cool thing done: " + fetched_raw_string)
And the test:
import unittest
from HMT import HMT
class test_HMT(unittest.TestCase):
def test_hmt_3_dec(self):
hmt = HMT()
string_to_test = "epsilon,ota,eta"
hmt.handle(string_to_test)
self.assertEqual(3, hmt.doCoolThings.calls)
def test_hmt_3(self):
hmt = HMT()
string_to_test = "alpha,beta,gamma"
hmt.handle(string_to_test)
self.assertEqual(3, len(hmt.buildedList))
But still are not working properly. When I run tests, I receive:
.F
======================================================================
FAIL: test_hmt_3_dec (myTest.test_HMT)
----------------------------------------------------------------------
Traceback (most recent call last):
File "D:\Users\danil\tmp\myDec\myTest.py", line 10, in test_hmt_3_dec
self.assertEqual(3, hmt.doCoolThings.calls)
AssertionError: 3 != 6
----------------------------------------------------------------------
Ran 2 tests in 0.001s
FAILED (failures=1)
More tests shows that the tests runs twice but the counter do not reset either in new instantiation.
Anyway, the initial idea was to dynamically put an observer in a internal class method and externaly fetches each time when those method is triggered (still, not something that seems to be solved using decorator).
Thanks alot for answers (and as a plus to leave powered up, if someone knows how to reset the counter in the decorator I will appreciate as well).
from HMT import HMT
count = 0
def counter(f):
def wrap(*args, **kwargs):
global count
count += 1
return f(*args, **kwargs)
return wrap
class test_HMT(unittest.TestCase):
def setUp(self):
self.hmt = HMT()
# Add decorator.
self.hmt_no_decorator = self.hmt.doCoolThings
self.hmt.doCoolThings = counter(self.hmt.doCoolThings)
def test_doCoolThings_count(self):
repeat = 3
[self.hmt.doCoolThings() for _ in range(repeat)]
self.assertEqual(counter, repeat)
def tearDown(self):
# Remove decorator.
self.hmt.doCoolThings = self.hmt_no_decorator
...
doCoolThings is not modified in the business code. You simply get the counting behaviour for testing.
You can get rid of the global var by replacing the count var with an object.. or by doing anything else really. But does it matter in testing?
I am currently designing a software which needs to manage a certain hardware setup.
The hardware setup is as following :
System - The system contains two identical devices, and has certain functionality relative to the entire system.
Device - Each device contains two identical sub devices, and has certain functionality relative to both sub devices.
Sub device - Each sub device has 4 configurable entities (Controlled via the same hardware command - thus I don't count them as a sub-sub device).
What I want to achieve :
I want to control all configurable entities via the system manager (the entities are counted in a serial way), meaning I would be able to do the following :
system_instance = system_manager_class(some_params)
system_instance.some_func(0) # configure device_manager[0].sub_device_manager[0].entity[0]
system_instance.some_func(5) # configure device_manager[0].sub_device_manager[1].entity[1]
system_instance.some_func(8) # configure device_manager[1].sub_device_manager[1].entity[0]
What I have thought of doing :
I was thinking of creating an abstract class, which contains all sub device functions (with a call to a conversion function) and have the system_manager, device_manager and sub_device_manager inherit it. Thus all classes will have the same function name and I will be able to access them via the system manager.
Something around these lines :
class abs_sub_device():
#staticmethod
def convert_entity(self):
sub_manager = None
sub_entity_num = None
pass
def set_entity_to_2(entity_num):
sub_manager, sub_manager_entity_num = self.convert_entity(entity_num)
sub_manager.some_func(sub_manager_entity_num)
class system_manager(abs_sub_device):
def __init__(self):
self.device_manager_list = [] # Initiliaze device list
self.device_manager_list.append(device_manager())
self.device_manager_list.append(device_manager())
def convert_entity(self, entity_num):
relevant_device_manager = self.device_manager_list[entity_num // 4]
relevant_entity = entity_num % 4
return relevant_device_manage, relevant_entity
class device_manager(abs_sub_device):
def __init__(self):
self.sub_device_manager_list = [] # Initiliaze sub device list
self.sub_device_manager_list.append(sub_device_manager())
self.sub_device_manager_list.append(sub_device_manager())
def convert_entity(self, entity_num):
relevant_sub_device_manager = self.sub_device_manager_list[entity_num // 4]
relevant_entity = entity_num % 4
return relevant_sub_device_manager, relevant_entity
class sub_device_manager(abs_sub_device):
def __init__(self):
self.entity_list = [0] * 4
def set_entity_to_2(self, entity_num):
self.entity_list[entity_num] = 2
The code is for generic understanding of my design, not for actual functionality.
The problem :
It seems to me that the system I am trying to design is really generic and that there must be a built-in python way to do this, or that my entire object oriented look at it is wrong.
I would really like to know if some one has a better way of doing this.
After much thinking, I think I found a pretty generic way to solve the issue, using a combination of decorators, inheritance and dynamic function creation.
The main idea is as following :
1) Each layer dynamically creates all sub layer relevant functions for it self (Inside the init function, using a decorator on the init function)
2) Each function created dynamically converts the entity value according to a convert function (which is a static function of the abs_container_class), and calls the lowers layer function with the same name (see make_convert_function_method).
3) This basically causes all sub layer function to be implemented on the higher level with zero code duplication.
def get_relevant_class_method_list(class_instance):
method_list = [func for func in dir(class_instance) if callable(getattr(class_instance, func)) and not func.startswith("__") and not func.startswith("_")]
return method_list
def make_convert_function_method(name):
def _method(self, entity_num, *args):
sub_manager, sub_manager_entity_num = self._convert_entity(entity_num)
function_to_call = getattr(sub_manager, name)
function_to_call(sub_manager_entity_num, *args)
return _method
def container_class_init_decorator(function_object):
def new_init_function(self, *args):
# Call the init function :
function_object(self, *args)
# Get all relevant methods (Of one sub class is enough)
method_list = get_relevant_class_method_list(self.container_list[0])
# Dynamically create all sub layer functions :
for method_name in method_list:
_method = make_convert_function_method(method_name)
setattr(type(self), method_name, _method)
return new_init_function
class abs_container_class():
#staticmethod
def _convert_entity(self):
sub_manager = None
sub_entity_num = None
pass
class system_manager(abs_container_class):
#container_class_init_decorator
def __init__(self):
self.device_manager_list = [] # Initiliaze device list
self.device_manager_list.append(device_manager())
self.device_manager_list.append(device_manager())
self.container_list = self.device_manager_list
def _convert_entity(self, entity_num):
relevant_device_manager = self.device_manager_list[entity_num // 4]
relevant_entity = entity_num % 4
return relevant_device_manager, relevant_entity
class device_manager(abs_container_class):
#container_class_init_decorator
def __init__(self):
self.sub_device_manager_list = [] # Initiliaze sub device list
self.sub_device_manager_list.append(sub_device_manager())
self.sub_device_manager_list.append(sub_device_manager())
self.container_list = self.sub_device_manager_list
def _convert_entity(self, entity_num):
relevant_sub_device_manager = self.sub_device_manager_list[entity_num // 4]
relevant_entity = entity_num % 4
return relevant_sub_device_manager, relevant_entity
class sub_device_manager():
def __init__(self):
self.entity_list = [0] * 4
def set_entity_to_value(self, entity_num, required_value):
self.entity_list[entity_num] = required_value
print("I set the entity to : {}".format(required_value))
# This is used for auto completion purposes (Using pep convention)
class auto_complete_class(system_manager, device_manager, sub_device_manager):
pass
system_instance = system_manager() # type: auto_complete_class
system_instance.set_entity_to_value(0, 3)
There is still a little issue with this solution, auto-completion would not work since the highest level class has almost no static implemented function.
In order to solve this I cheated a bit, I created an empty class which inherited from all layers and stated to the IDE using pep convention that it is the type of the instance being created (# type: auto_complete_class).
Does this solve your Problem?
class EndDevice:
def __init__(self, entities_num):
self.entities = list(range(entities_num))
#property
def count_entities(self):
return len(self.entities)
def get_entity(self, i):
return str(i)
class Device:
def __init__(self, sub_devices):
self.sub_devices = sub_devices
#property
def count_entities(self):
return sum(sd.count_entities for sd in self.sub_devices)
def get_entity(self, i):
c = 0
for index, sd in enumerate(self.sub_devices):
if c <= i < sd.count_entities + c:
return str(index) + " " + sd.get_entity(i - c)
c += sd.count_entities
raise IndexError(i)
SystemManager = Device # Are the exact same. This also means you can stack that infinite
sub_devices1 = [EndDevice(4) for _ in range(2)]
sub_devices2 = [EndDevice(4) for _ in range(2)]
system_manager = SystemManager([Device(sub_devices1), Device(sub_devices2)])
print(system_manager.get_entity(0))
print(system_manager.get_entity(5))
print(system_manager.get_entity(15))
I can't think of a better way to do this than OOP, but inheritance will only give you one set of low-level functions for the system manager, so it wil be like having one device manager and one sub-device manager. A better thing to do will be, a bit like tkinter widgets, to have one system manager and initialise all the other managers like children in a tree, so:
system = SystemManager()
device1 = DeviceManager(system)
subDevice1 = SubDeviceManager(device1)
device2 = DeviceManager(system)
subDevice2 = SubDeviceManager(device2)
#to execute some_func on subDevice1
system.some_func(0, 0, *someParams)
We can do this by keeping a list of 'children' of the higher-level managers and having functions which reference the children.
class SystemManager:
def __init__(self):
self.children = []
def some_func(self, child, *params):
self.children[child].some_func(*params)
class DeviceManager:
def __init__(self, parent):
parent.children.append(self)
self.children = []
def some_func(self, child, *params):
self.children[child].some_func(*params)
class SubDeviceManager:
def __init__(self, parent):
parent.children.append(self)
#this may or may not have sub-objects, if it does we need to make it its own children list.
def some_func(self, *params):
#do some important stuff
Unfortunately, this does mean that if we want to call a function of a sub-device manager from the system manager without having lots of dots, we will have to define it again again in the system manager. What you can do instead is use the built-in exec() function, which will take in a string input and run it using the Python interpreter:
class SystemManager:
...
def execute(self, child, function, *args):
exec("self.children[child]."+function+"(*args)")
(and keep the device manager the same)
You would then write in the main program:
system.execute(0, "some_func", 0, *someArgs)
Which would call
device1.some_func(0, someArgs)
Here's what I'm thinking:
SystemManager().apply_to_entity(entity_num=7, lambda e: e.value = 2)
class EntitySuperManagerMixin():
"""Mixin to handle logic for managing entity managers."""
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs) # Supports any kind of __init__ call.
self._entity_manager_list = []
def apply_to_entity(self, entity_num, action):
relevant_entity_manager = self._entity_manager_list[index // 4]
relevant_entity_num = index % 4
return relevant_entity_manager.apply_to_entity(
relevant_entity_num, action)
class SystemManager(EntitySuperManagerMixin):
def __init__(self):
super().__init__()
# An alias for _entity_manager_list to improve readability.
self.device_manager_list = self._entity_manager_list
self.device_manager_list.extend(DeviceManager() for _ in range(4))
class DeviceManager(EntitySuperManagerMixin):
def __init__(self):
super().__init__()
# An alias for _entity_manager_list to improve readability.
self.sub_device_manager_list = self._entity_manager_list
self.sub_device_manager_list.extend(SubDeviceManager() for _ in range(4))
class SubDeviceManager():
"""Manages entities, not entity managers, thus doesn't inherit the mixin."""
def __init__(self):
# Entities need to be classes for this idea to work.
self._entity_list = [Entity() for _ in range(4)]
def apply_to_entity(self, entity_num, action):
return action(self._entity_list[entity_num])
class Entity():
def __init__(self, initial_value=0):
self.value = initial_value
With this structure:
Entity-specific functions can stay bound to the Entity class (where it belongs).
Manager-specific code needs to be updated in two places: EntitySuperManagerMixin and the lowest level manager (which would need custom behavior anyway since it deals with the actual entities, not other managers).
The way i see it if you want to dynamically configure different part of system you need some sort of addressing so if you input an ID or address with some parameter the system will know with address on which sub sistem you are talking about and then configure that system with parameter.
OOP is quite ok for that and then you can easily manipulate such data via bitwise operators.
So basic addressing is done via binary system , so to do that in python you need first to implement an address static attribute to your class with perhaps some basic further detailing if system grows.
Basic implementation of addres systems is as follows:
bin(71)
1010 1011
and if we divide it into nibbles
1010 - device manager 10
1011 - sub device manager 11
So in this example we have system of 15 device managers and 15 sub device menagers, and every device and sub device manager has its integer address.So let's say you want to access device manager no10 with sub device manager no11. You would need their address which is in binary 71 and you would go with:
system.config(address, parameter )
Where system.config funcion would look like this:
def config(self,address, parameter):
device_manager = (address&0xF0)>>4 #10
sub_device_manager = address&0xf # 11
if device_manager not in range(self.devices): raise LookupError("device manager not found")
if sub_device_manager not in range(self.devices[device_manager].device): raise LookupError("sub device manager not found")
self.devices[device_manager].device[sub_device_manager].implement(parameter)
In layman you would tell system that sub_device 11 from device 10 needs configuration with this parameter.
So how would this setup look in python inheritance class of some base class of system that could be then composited/inherited to different classes:
class systems(object):
parent = None #global parent element, defaults to None well for simplicity
def __init__(self):
self.addrMASK = 0xf # address mask for that nibble
self.addr = 0x1 # default address of that element
self.devices = [] # list of instances of device
self.data = { #some arbitrary data
"param1":"param_val",
"param2":"param_val",
"param3":"param_val",
}
def addSubSystem(self,sub_system): # connects elements to eachother
# checks for valiability
if not isinstance(sub_system,systems):
raise TypeError("defined input is not a system type") # to prevent passing an integer or something
# appends a device to system data
self.devices.append(sub_system)
# search parent variables from sub device manager to system
obj = self
while 1:
if obj.parent is not None:
obj.parent.addrMASK<<=4 #bitshifts 4 bits
obj.parent.addr <<=4 #bitshifts 4 bits
obj = obj.parent
else:break
#self management , i am lazy guy so i added this part so i wouldn't have to reset addresses manualy
self.addrMASK <<=4 #bitshifts 4 bits
self.addr <<=4 #bitshifts 4 bits
# this element is added so the obj address is coresponding to place in list, this could be done more eloquently but i didn't know what are your limitations
if not self.devices:
self.devices[ len(self.devices)-1 ].addr +=1
self.devices[ len(self.devices)-1 ].parent = self
# helpful for checking data ... gives the address of system
def __repr__(self):
return "system at {0:X}, {1:0X}".format(self.addr,self.addrMASK)
# extra helpful lists data as well
def __str__(self):
data = [ '{} : {}\n'.format(k,v) for k,v in self.data.items() ]
return " ".join([ repr(self),'\n',*data ])
#checking for data, skips looping over sub systems
def __contains__(self,system_index):
return system_index-1 in range(len(self.data))
# applying parameter change -- just an example
def apply(self,par_dict):
if not isinstance(par_dict,dict):
raise TypeError("parameter must be a dict type")
if any( key in self.data.keys() for key in par_dict.keys() ):
for k,v in par_dict.items():
if k in self.data.keys():
self.data[k]=v
else:pass
else:pass
# implementing parameters trough addresses
def implement(self,address,parameter_dictionary):
if address&self.addrMASK==self.addr:
if address-self.addr!=0:
item = (address-self.addr)>>4
self.devices[item-1].implement( address-self.addr,parameter_dictionary )
else:
self.apply(parameter_dictionary)
a = systems()
b = systems()
a.addSubSystem(b)
c = systems()
b.addSubSystem(c)
print('a')
print(a)
print('')
print('b')
print(b)
print('')
print('c')
print(c)
print('')
a.implement(0x100,{"param1":"a"})
a.implement(0x110,{"param1":"b"})
a.implement(0x111,{"param1":"c"})
print('a')
print(a)
print('')
print('b')
print(b)
print('')
print('c')
print(c)
print('')
i have this piece of code which is a class __init__ method and takes two arguments.
def __init__(self, port_type, request):
self.log = Log(__name__, True)
self.request = request
self.sitecode = port_type.sitecode.upper()
self.browser_default_lang = self.request.META['HTTP_ACCEPT_LANGUAGE'].split(',')[0]
self.active_lang = self.request.session.get('lang', self.browser_default_lang.lower())
self.static_folder = 'static_%s_%s' % (self.sitecode, self.SITE_TEMPLATES_RESOURCES_SUFFIX)
self.template_path = os.path.join(settings.MEDIA_ROOT, self.static_folder)
self.template_path_port_type = '%s_%s' % (self.template_path, self.port_type.hash)
self.site_media_path = os.path.join(settings.MEDIA_URL, self.static_folder)
self.site_port_type_media_path = '%s_%s' % (self.site_media_path, self.port_type.hash)
self.site_config = SiteConfig.objects.get(sitecode=self.sitecode)
self.site = UmSite.objects.get(code=self.port_type.sitecode)
self.context = {}
I find it difficult to write unit tests for this. I should really write the tests first but somehow I ended up with this and have to refactor and am writing them now.
Use a mock request that gives you deterministic data, without connecting to the internet. For example, make a request object that returns some fixed string for request.META, and a session object that returns a fixed string for session.get(...), etc. Then assert that self.active_lang and other properties that need to be set have the right values.