Rositsa Zlateva
Full Stack Python Developer and lecturer
Debug and Profile your Python code
Lecturer
Rositsa Kotseva
- Full Stack Developer at HedgeServ Bulgaria
- Python Lecturer at the HackBulgaria Academy
Content
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Debug
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What? Why? How?
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Python Debug tools
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Code Profiling
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What? Why? How?
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Python Profiling Tools
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Profile visualization
Why did I choose this topic?
What is debugging?
The process of finding/detecting and fixing existing and potential bugs is called DEBUGGING
Why do we debug our code?
How to debug?
print()
def sum_number_digits(number):
print(number)
digits = []
for ch in str(number):
print(ch)
print(type(ch))
digits.append(ch)
print(digits)
return sum(digits)
print(sum_number_digits(45))
print(sum_number_digits('4O'))Logging
import logging
logging.basicConfig(
filename='example.log',
level=logging.DEBUG,
format='%(asctime)s:%(levelname)s:%(message)s'
)
def sum_number_digits(number):
logging.debug(number)
digits = []
for ch in str(number):
logging.debug(ch)
logging.debug(type(ch))
digits.append(ch)
logging.debug(digits)
return sum(digits)
print(sum_number_digits(45))
print(sum_number_digits('4O'))
Log result
2021-03-14 22:47:12,091:DEBUG:45
2021-03-14 22:47:12,091:DEBUG:4
2021-03-14 22:47:12,091:DEBUG:<class 'str'>
2021-03-14 22:47:12,091:DEBUG:5
2021-03-14 22:47:12,091:DEBUG:<class 'str'>
2021-03-14 22:47:12,091:DEBUG:['4', '5']
Log & print based libraries
- Loguru - https://github.com/Delgan/loguru
- structlog - https://pypi.org/project/structlog/
- colorlog - https://pypi.org/project/colorlog/
- IceCream - https://github.com/gruns/icecream
- PySnooper - https://github.com/cool-RR/PySnooper/
logger.add("out.log", backtrace=True, diagnose=True)
def func(a, b):
return a / b
def nested(c):
try:
func(5, c)
except ZeroDivisionError:
logger.exception("What?!")
nested(0)Loguru example
2018-07-17 01:38:43.975 | ERROR | __main__:nested:10 - What?!
Traceback (most recent call last):
File "test.py", line 12, in <module>
nested(0)
└ <function nested at 0x7f5c755322f0>
> File "test.py", line 8, in nested
func(5, c)
│ └ 0
└ <function func at 0x7f5c79fc2e18>
File "test.py", line 4, in func
return a / b
│ └ 0
└ 5
ZeroDivisionError: division by zeroDebuggers
Debugger is a program that assists in the detection and correction of errors in computer programs.
Python Debuggers
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pdb - https://docs.python.org/3/library/pdb.html -
pdb++ - https://github.com/pdbpp/pdbpp -
IPython pdb - https://github.com/gotcha/ipdb -
hunter - https://github.com/ionelmc/python-hunter
pdb commands
- python -m pdb.py <file_name>.py [args]
- import pdb; pdb.set_trace()
- breakpoint()
- help [command]
What is Profiling?
A set of statistics that describes how often and for how long various parts of the program executed
Why do we profile our code?
How to profile?
Python Profiling tools
- time/timeit - https://docs.python.org/3/library/timeit.html
- cProfile - https://docs.python.org/3/library/profile.html
- PyInstrument - https://github.com/joerick/pyinstrument
- PySpy - https://github.com/benfred/py-spy
- Yappi - https://github.com/sumerc/yappi/
Profiling Statistics
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Total number of calls
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primitive calls
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ncalls
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tottime
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percall
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cumtime
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percall #2
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filename:lineno
Profiling example
Profile Visualization
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SnakeViz
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pyprof2calltree
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gprof2dot
SnakeViz example
Memory Profiler
Debug and profile Django
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Django Debug ToolBar
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django-cprofile-middleware
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django-profiler
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Django Silk
Tips & Tricks
& useful links
Thank you!
Contacts
LinkedIn - https://www.linkedin.com/in/rositsa-kotseva/
Serverless WebSockets with AWS Lambda and API Gateway
Next event
GitHub - https://github.com/rositsazz
debug-and-profile
By Rositsa Zlateva
