#!/usr/bin/env python
import threading
def background_setup():
# Explicitly importing this from the context of the child thread
from config import settings
print(settings.ROOT_DIR)
# Spawn a thread to background preparation tasks
t = threading.Thread(target=background_setup)
t.start()
# Do other things during initialization
t.join()
# Ready to take traffic
settings.py
import os
import sys
ROOT_DIR = None
def setup():
global ROOT_DIR
ROOT_DIR = os.path.dirname(sys.modules['__main__'].__file__)
# Do something slow
运行这个程序会产生一个属性错误:
>>> import main
>>> Exception in thread Thread-1:
Traceback (most recent call last):
File "C:\Python2714\lib\threading.py", line 801, in __bootstrap_inner
self.run()
File "C:\Python2714\lib\threading.py", line 754, in run
self.__target(*self.__args, **self.__kwargs)
File "main.py", line 6, in background_setup
from config import settings
File "config\settings.py", line 34, in <module>
ROOT_DIR = get_root()
File "config\settings.py", line 31, in get_root
return os.path.dirname(sys.modules['__main__'].__file__)
AttributeError: 'module' object has no attribute '__file__'
...因此是基于线程的解决方案
位置独立
使用与之前相同的应用程序结构,但修改settings.py
import os
import sys
import inspect
import platform
import threading
ROOT_DIR = None
def setup():
main_id = None
for t in threading.enumerate():
if t.name == 'MainThread':
main_id = t.ident
break
if not main_id:
raise RuntimeError("Main thread exited before execution")
current_main_frame = sys._current_frames()[main_id]
base_frame = inspect.getouterframes(current_main_frame)[-1]
if platform.system() == 'Windows':
filename = base_frame.filename
else:
filename = base_frame[0].f_code.co_filename
global ROOT_DIR
ROOT_DIR = os.path.dirname(os.path.abspath(filename))
main_id = None
for t in threading.enumerate():
if t.name == 'MainThread':
main_id = t.ident
break
if not main_id:
raise RuntimeError("Main thread exited before execution")
# You can first retrieve the env variable PROJECT_DIR.
# If not set, get the python interpreter location and strip off the string till envs inclusiv...
if os.getenv('PROJECT_DIR'):
PROJECT_DIR = os.getenv('PROJECT_DIR')
else:
PYTHON_PATH = sys.executable
path_rem = os.path.join('envs', 'default', 'bin', 'python')
PROJECT_DIR = py_path.split(path_rem)[0]
import pathlib
import os
def get_project_root():
"""
There is no way in python to get project root. This function uses a trick.
We know that the function that is currently running is in the project.
We know that the root project path is in the list of PYTHONPATH
look for any path in PYTHONPATH list that is contained in this function's path
Lastly we filter and take the shortest path because we are looking for the root.
:return: path to project root
"""
apth = str(pathlib.Path().absolute())
ppth = os.environ['PYTHONPATH'].split(':')
matches = [x for x in ppth if x in apth]
project_root = min(matches, key=len)
return project_root
def get_project_root_dir() -> str:
"""
Returns the name of the project root directory.
:return: Project root directory name
"""
# stack trace history related to the call of this function
frame_stack: [FrameInfo] = inspect.stack()
# get info about the module that has invoked this function
# (index=0 is always this very module, index=1 is fine as long this function is not called by some other
# function in this module)
frame_info: FrameInfo = frame_stack[1]
# if there are multiple calls in the stacktrace of this very module, we have to skip those and take the first
# one which comes from another module
if frame_info.filename == __file__:
for frame in frame_stack:
if frame.filename != __file__:
frame_info = frame
break
# path of the module that has invoked this function
caller_path: str = frame_info.filename
# absolute path of the of the module that has invoked this function
caller_absolute_path: str = os.path.abspath(caller_path)
# get the top most directory path which contains the invoker module
paths: [str] = [p for p in sys.path if p in caller_absolute_path]
paths.sort(key=lambda p: len(p))
caller_root_path: str = paths[0]
if not os.path.isabs(caller_path):
# file name of the invoker module (eg: "mymodule.py")
caller_module_name: str = Path(caller_path).name
# this piece represents a subpath in the project directory
# (eg. if the root folder is "myproject" and this function has ben called from myproject/foo/bar/mymodule.py
# this will be "foo/bar")
project_related_folders: str = caller_path.replace(os.sep + caller_module_name, '')
# fix root path by removing the undesired subpath
caller_root_path = caller_root_path.replace(project_related_folders, '')
dir_name: str = Path(caller_root_path).name
return dir_name
from pathlib import Path
ROOT_DIR = Path(__file__).parent.parent
使用ROOT_DIR:
main.py < / p >
# imports must be relative,
# not from the root of the project,
# but from the root of the main package.
# Not this way:
# from RootPackge.definitions import ROOT_DIR
# But like this:
from definitions import ROOT_DIR
# Here we use ROOT_DIR
# get path to MyProject/drivers
drivers_dir = ROOT_DIR / 'drivers'
# Thus, you can get the path to any directory
# or file from the project root
driver = webdriver.Firefox(drivers_dir)
driver.get('http://www.google.com')
import os
from pathlib import Path
class Config:
try:
import beacon
print(f"'import beacon' -> {os.path.dirname(os.path.abspath(beacon.__file__))}") # only for demo purposes
print(f"'import beacon' -> {Path(beacon.__file__).parent.resolve()}") # only for demo purposes
except ModuleNotFoundError as e:
print(f"ModuleNotFoundError: import beacon failed with {e}. "
f"Please. create a file called beacon.py and place it to the project root directory.")
project_root = Path(beacon.__file__).parent.resolve()
input_dir = project_root / 'input'
output_dir = project_root / 'output'
if __name__ == '__main__':
c = Config()
print(f"Config.project_root: {c.project_root}")
print(f"Config.input_dir: {c.input_dir}")
print(f"Config.output_dir: {c.output_dir}")
from from_root import from_root, from_here
# path to config file at the root of your project
# (no matter from what file of the project the function is called!)
config_path = from_root('config.json')
# path to the data.csv file at the same directory where the callee script is located
# (has nothing to do with the current working directory)
data_path = from_here('data.csv')
from groo.groo import get_root
root_folder = get_root(".my_hidden_root_file")
就是这样!
它只执行以下函数:
def get_root(rootfile):
import os
from pathlib import Path
d = Path(os.getcwd())
found = 0
while found == 0:
if os.path.isfile(os.path.join(d, rootfile)):
found = 1
else:
d=d.parent
return d