From 3c1047937c92014d314aad56b9749a9e629b9b92 Mon Sep 17 00:00:00 2001 From: Karenzz Date: Wed, 19 Apr 2023 00:51:05 +0200 Subject: [PATCH] Update page 'Day9 homework - Karen' --- Day9 homework - Karen.md | 177 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 177 insertions(+) create mode 100644 Day9 homework - Karen.md diff --git a/Day9 homework - Karen.md b/Day9 homework - Karen.md new file mode 100644 index 0000000..73d48c9 --- /dev/null +++ b/Day9 homework - Karen.md @@ -0,0 +1,177 @@ +Today's homework will be to build a tool to introspect Python packages, from the perspective of the currently running Python interpreter. + +**1. Use `importlib.util.find_spec` to create a function that takes a Python module or package name, and returns the total number of bytes in the cached `.pyc` file, or the total number of bytes in the `.py` file if there is no cached bytecode. You can use the os.stat command to get the size of a file.** + +``` +import importlib.util +import os + +def get_module_size(module_name): + spec = importlib.util.find_spec(module_name) + + if spec is not None and spec.has_location: + # If the module is found and has a location, check for .pyc file first + pyc_file_path = spec.origin + 'c' + if os.path.exists(pyc_file_path): + return os.stat(pyc_file_path).st_size + else: + # If .pyc file doesn't exist, check for .py file + py_file_path = spec.origin + if os.path.exists(py_file_path): + return os.stat(py_file_path).st_size + + return 0 # Return 0 if no .pyc or .py file found +``` + +**2. Create another function that uses the last function to see how many bytes are in all the modules listed in sys.modules.** + +``` +import sys + +def get_total_module_size(): + total_size = 0 + for module_name in sys.modules: + module_size = get_module_size(module_name) + total_size += module_size + + return total_size + +if __name__ == '__main__' and __package__ is None: + __spec__ = importlib.util.spec_from_file_location('__main__', __file__) +total_size = get_total_module_size() +print("Total size of all modules in sys.modules: {} bytes".format(total_size)) +``` + +**3. Run your Python interpreter like you would normally, using Jupyter, and run the last function. How many bytes are being used?** +I run this script in visual studio and change the python interpreter path including the defualt python3.11, the one in my anaconda environment, and the pandas environment. It seems when I use a python interpreter that ignores environment variables or only loads the modules that came with the original build of the Python interpreter, the total size of all modules in `sys.modules` would likely be relatively small compared to a Python environment with additional third-party modules installed (just like my anaconda environment, where I have intalled third-party modules such as fastapi). + + +![bytes](https://gogs.gtsplab.com:5432/j/python-bootcamp/raw/Branch_Karen/bytes%20module.png) + + +**4. Now, run the same function, but start the Python interpreter in Powershell (Windows), or the regular shell (MacOS/Linux) with the `-E` flag, which ignores environment variables and should only load the modules that came with the original build of the Python interpreter. How many bytes are being used now?** +I run the same function, but a warning says name '__file__' is not defined. The reason for this may be the fact that the `__file__` attribute is not automatically defined in the global namespace when running a script in Powershell (and I am not sure whether this issue is caused by my system's setting). So, to fix it, I just update my last function like this: + +``` +import inspect + +if __name__ == '__main__' and __package__ is None: + # Get the path of the currently running script + script_path = inspect.getframeinfo(inspect.currentframe()).filename + __spec__ = importlib.util.spec_from_loader('__main__', None, origin=script_path) + +total_size = get_total_module_size() +print("Total size of all modules in sys.modules: {} bytes".format(total_size)) +``` +The result says that the total size of all modules in sys.modules: 671553 bytes. + +**5. With only the `sys` module loaded, look at the `sys.modules` dict. What is the type of the value of the `os` key?** + +``` + +``` + +**6. Import the os module. What happens when you type `type(os)`?** +It returns the type of the `os` module as ``. + +**7. Restart the Python interpreter. Can you figure out how to call `os.getlogin()` without saying `import os`?** + +``` +import builtins + +# Access the os module from globals() +os = globals().get('os', None) + +# Check if os module is available +if os is not None: + # Call os.getlogin() + username = os.getlogin() + print("Username:", username) +else: + print("os module not available") +``` + +**8. If you can, explain why this works and quote the relevant sections of section 5 in the language reference.** +"Functions such as importlib.import_module() and built-in __import__() can also be used to invoke the import machinery." +"When a module is first imported, Python searches for the module and if found, it creates a module object 1, initializing it. +"when the name binding operation is executed, the Python interpreter searches several namespaces, in this order, to find the specified name: the local namespace, the global namespace, the built-in namespace." + +**9. Using the functions you created above and `sys.modules`, create a module designed to be run from the command line (`python -m myscript.py`) that generates a report summarizing the module environment, and break down the percentages of bytecode modules, DSO modules (these have `file` end in `.so` or `.dll`), and normal python code.** + +``` +import os +import sys +import importlib.util +import types + + +def get_bytecode_size(module_name): + """Get the size of the cached .pyc bytecode file for a module.""" + spec = importlib.util.find_spec(module_name) + if spec and spec.origin.endswith('.py'): + pyc_file = importlib.util.cache_from_source(spec.origin) + if os.path.exists(pyc_file): + return os.path.getsize(pyc_file) + return 0 + + +def get_dso_size(module_name): + """Get the size of the DSO (Dynamic Shared Object) module file for a module.""" + spec = importlib.util.find_spec(module_name) + if spec and spec.origin.endswith(('.so', '.dll')): + return os.path.getsize(spec.origin) + return 0 + + +def generate_module_report(): + """Generate a report summarizing the module environment.""" + total_modules = len(sys.modules) + bytecode_size = sum(get_bytecode_size(module_name) for module_name in sys.modules) + dso_size = sum(get_dso_size(module_name) for module_name in sys.modules) + python_size = sum( + sys.modules[module_name].__sizeof__() + for module_name in sys.modules + if isinstance(sys.modules[module_name], types.ModuleType) + ) + total_size = bytecode_size + dso_size + python_size + + # Calculate percentage of each type of module + bytecode_percent = bytecode_size / total_size * 100 + dso_percent = dso_size / total_size * 100 + python_percent = python_size / total_size * 100 + + # Generate the report + report = f"Total modules: {total_modules}\n" + report += f"Total size: {total_size} bytes\n" + report += f"Bytecode modules: {bytecode_percent:.2f}% ({bytecode_size} bytes)\n" + report += f"DSO modules: {dso_percent:.2f}% ({dso_size} bytes)\n" + report += f"Python code modules: {python_percent:.2f}% ({python_size} bytes)\n" + + return report + +if __name__ == '__main__' and __package__ is None: + __spec__ = importlib.util.spec_from_file_location('__main__', __file__) + report = generate_module_report() + print(report) +``` + + +![Q9](https://gogs.gtsplab.com:5432/j/python-bootcamp/raw/Branch_Karen/Q9.png) + + + +**10. Add a feature to the script which looks at `file` for each module, trims the filename to get the directory name, then prints out a histogram of how many modules are in each directory name. If you can't find a text histogram output library in anaconda's built-in modules, just print out the `*` character for each module.** + +``` + # Generate histogram of module directory names + dir_histogram = defaultdict(int) + for module_name in sys.modules: + module_file = sys.modules[module_name].__file__ + if module_file: + module_dir = os.path.dirname(module_file) + dir_histogram[module_dir] += 1 + + report += "\nModule Directory Histogram:\n" + for module_dir, count in dir_histogram.items(): + report += f"{module_dir}: {'*' * count}\n" +``` \ No newline at end of file