I have a Python program that consists of several modules. The "main" module creates a file variable log_file for logging the output; all the other modules would need to write to that file as well.
However, I don't want to import the "main" module into other modules, since it would be a really weird dependency (not to mention it might not even work due to circular dependency).
Where, then, should I store the log_file variable?
EDIT:
Following #pyfunc answer - would this be ok:
--- config.py ---
# does not mention log_file
# unless it's required for syntax reasons; in which case log_file = None
# ...
--- main.py ---
from datetime import datetime
import config.py
log_filename = str(datetime.now()) + '.txt'
config.log_file = open(log_filename, 'w')
# ...
--- another_module.py ---
import config.py
# ...
config.log_file.write(some_stuff)
Put the "global" variable in a "settings" module.
settings.py
log_file = "/path/to/file"
main.py
import settings
import logging
logging.basicConfig(filename=settings.log_file,level=logging.DEBUG)
logging.debug("This should go to the log file")
other_module.py
import logging
logging.debug("This is a message from another place.")
While the logging module may solve your immediate problem and many others, the settings module pattern is useful for a lot of other things besides log file names. It is used by Django to configure just about everything.
One way is to take all that code into another module so that you could import it in main file and other modules as well.
Hope you have checked on : http://docs.python.org/library/logging.html
Related
I have a Python project in which I have the following folder structure:
> root
> download_module
> __init__.py
> downloadProcess.py
> sharedFunctions.py
> someHelper.py
> useSharedFunction.py
The download_module/__init__.py has the following code:
from .sharedFunctions import stringArgumentToDate
from .downloadProcess import downloadProcessMethod
The sharedFunctions.py file contains the following function:
def stringArgumentToDate(arg):
dateformat = "%m/%d/%Y"
date = None
if arg.isnumeric():
date = datetime.fromtimestamp(int(arg))
if date == None:
date = datetime.strptime(arg, dateformat)
return date
Then on the useSharedFunction.py I try to import the shared function and use it like this.
from download_module import stringArgumentToDate
from download_module import downloadProcessMethod
def main():
arg = '03/14/2022'
dateArg = stringArgumentToDate(arg)
if __name__ == '__main__':
main()
When I try to run this by using python3 useSharedFunction.py I got the following error:
Traceback (most recent call last):
File "useSharedFunction.py", line 4, in <module>
from download_module import stringArgumentToDate
File "/Users/jacobo/Documents/project/download_module/__init__.py", line 2, in <module>
from .download_module import downloadAndProcessMethod
File "/Users/jacobo/Documents/project/download_module/downloadProcess.py", line 10, in <module>
from sharedFunctions import stringArgumentToDate, otherFunction
ModuleNotFoundError: No module named 'sharedFunctions'
I do believe the error is in downloadProcess since at the beggining of the file we got this import:
from sharedFunctions import stringArgumentToDate, otherFunction
from someHelper import Helper
Which refers to sibling files.
However I'm unsure what will be a proper fix to allow to run the downloadProcess.py main independently but also, being able to call it one of its method from a root or any other file out of the module.
Consider this structure:
┬ module
| ├ __init__.py
| ├ importing_submodule.py
| └ some_submodule.py
├ __main__.py
├ some_submodule.py
└ module_in_parent_dir.py
with content:
__main__.py
import module
/module/__init__.py
from . import importing_submodule
/module/importing_submodule.py
from some_submodule import SomeClass
/module/some_submodule.py
print("you imported from module")
class SomeClass:
pass
/some_submodule.py
print("you imported from root")
class SomeClass:
pass
/module_in_parent_dir.py
class SomeOtherClass:
pass
How sibling import works
(skip this section if you know already)
Now lets run __main__.py and it will say "you imported from root".
But if we change code a bit..
/module/importing_submodule.py
from module.some_submodule import SomeClass
It now says "You imported from module" as we wanted, probably with scary red line in IDE saying "Unresolved reference" if you didn't config working directory in IDE.
How this happen is simple: script root(Current working directory) is decided by main script(first script that's running), and python uses namespaces.
Python's import system uses 2 import method, and for convenience let's call it absolute import and relative import.
Absolute import: Import from dir listed in sys.path and current working directory
Relative import: Import relative to the very script that called import
And what decide the behavior is whether we use . at start of module name or not.
Since we imported by from some_submodule without preceeding dot, python take it as 'Absolute import'(the term we decided earlier).
And then when we also specified module name like from module.some_submodule python looks for module in path list or in current working directory.
Of course, this is never a good idea; script root can change via calls like os.chdir() then submodules inside module folder may get lost.
Therefore, the best practices for sibling import is using relative import inside module folder.
/module/importing_submodule.py
from .some_submodule import SomeClass
Making script that work in both way
To make submodule import it's siblings when running as main script, yet still work as submodule when imported by other script, then use try - except and look for ImportError.
For importing_submodule.py as an example:
/module/importing_submodule.py
try:
from .some_submodule import SomeClass
except ImportError:
# attempted relative import with no known parent package
# because this is running as main script, there's no parent package.
from some_submodule import SomeClass
Importing modules from parent directory is a bit more tricky.
Since submodule is now main script, relative import to parent level directory doesn't work.
So we need to add the parent directory to sys.path, when the script is running as main script.
/module/importing_submodule.py
try:
from .some_submodule import SomeClass
except ImportError:
# attempted relative import with no known parent package
# because this is running as main script, there's no parent package.
from some_submodule import SomeClass
# now since we don't have parent package, we just append the path.
from sys import path
import pathlib
path.append(pathlib.Path(__file__).parent.parent.as_posix())
print("Importing module_in_parent_dir from sys.path")
else:
print("Importing module_in_parent_dir from working directory")
# Now either case we have parent directory of `module_in_parent_dir`
# in working dir or path, we can import it
# might need to suppress false IDE warning this case.
# noinspection PyUnresolvedReferences
from module_in_parent_dir import SomeOtherClass
Output:
"C:\Program Files\Python310\python.exe" .../module/importing_module.py
you imported from module
Importing module_in_parent_dir from sys.path
Process finished with exit code 0
"C:\Program Files\Python310\python.exe" .../__main__.py
you imported from module
Importing module_in_parent_dir from working directory
Process finished with exit code 0
My directory looks like this :
- HttpExample:
- __init__.py
- DBConnection.py
- getLatlong.py
I want to import DBConnection and import getLatlong in __init__.py. There is no error in my __init__.py until I run it, I received :
System.Private.CoreLib: Exception while executing function: Functions.HttpExample. System.Private.CoreLib: Result: Failure
Exception: ModuleNotFoundError: No module named 'getLatlong'
I'm trying to use function in getLatlong to use the information input by user from __init__.py to getLatlong. Below is the code:
__init__.py :
from getLatlong import result
from DBConnection import blobService, container_name, account_key, file_path
def main(req: func.HttpRequest) -> func.HttpResponse:
logging.info('Python HTTP trigger function processed a request.')
section = req.params.get('section')
bound = req.params.get('bound')
km_location = req.params.get('km_location')
location = req.params.get('location')
if not section:
try:
req_body = req.get_json()
except ValueError:
pass
else:
section = req_body.get('section')
if section and bound and km_location:
result(section, km_location, bound, location).getResult() #HERE
return func.HttpResponse(f"Hello {section}, {bound}!")
#elif section is None or bound is None or km_location is None:
# return func.HttpResponse("All values are mandatory!")
I am also receiving compile error at getLatlong to import DBConnection to this class. The following values will pass to getLatlong.py. The code :
from DBConnection import blobService, container_name, account_key, file_path #Another import error here says : Unable to import DBConnection
class result:
def __init__(self, section, bound, km_location, location):
self.section = section
self.bound = bound
self.km_location = km_location
self.location = location
def getResult(self):
print(self.section)
print(self.bound)
print(self.km_location)
print(self.location)
I've tried every way to import these files before I lost my mind..
You get these errors, because Python does not know where to look for the files you want to import. Depending on which Python version you are using, I see three ways to solve this:
You could add HttpExample to your PYTHONPATH and than your imports should work as you have them currently.
Another way would be to use the sys module and append the path to HttpExample, e.g.
import sys
sys.path.append('PATH/TO/HttpExample')
But you would have to do this in all files, where you want to import something from the parent folder.
Or you use relative imports, which have been available since Python 2.5 (See PEP238). Those are only available in modules, but as you have your __init__.py file, it should work. For relative imports you are using dots . to tell Python where to look for the import. One dot . tells Python to look for the desired import in the parent folder. You could also use .. to go up two levels. But one level should be enough in your case.
So in your case changing your code to this, should solve your problem.
In __init.py__:
from .getLatlong import result
from .DBConnection import blobService, container_name, account_key, file_path
In getLangLong.py:
from .DBConnection import blobService, container_name, account_key, file_path
You could try from __app__.HttpExample import getLatlong.
There is a document about how to import module in the Shared Code folder. Check this doc:Folder structure.
It says Shared code should be kept in a separate folder in __app__. And in my test this could work for me.
Write your code with a nice logger
import logging
def init_logging():
logFormatter = logging.Formatter("[%(asctime)s] %(levelname)s::%(module)s::%(funcName)s() %(message)s")
rootLogger = logging.getLogger()
LOG_DIR = os.getcwd() + '/' + 'logs'
if not os.path.exists(LOG_DIR):
os.makedirs(LOG_DIR)
fileHandler = logging.FileHandler("{0}/{1}.log".format(LOG_DIR, "g2"))
fileHandler.setFormatter(logFormatter)
rootLogger.addHandler(fileHandler)
rootLogger.setLevel(logging.DEBUG)
consoleHandler = logging.StreamHandler()
consoleHandler.setFormatter(logFormatter)
rootLogger.addHandler(consoleHandler)
return rootLogger
logger = init_logging()
works as expected. Logging using logger.debug("Hello! :)") logs to file and console.
In a second step you want to import an external module which is also logging using logging module:
Install it using pip3 install pymisp (or any other external module)
Import it using from pymisp import PyMISP (or any other external module)
Create an object of it using self.pymisp = PyMISP(self.ds_model.api_url, self.ds_model.api_key, False, 'json') (or any other...)
What now happens is, that every debug log output from the imported module is getting logged to the log file and the console. The question now is, how to set a different (higher) log level for the imported module.
As Meet Sinoja and anishtain4 pointed out in the comments, the best and most generic method is to retrieve the logger by the name of the imported module as follows:
import logging
import some_module_with_logging
logging.getLogger("some_module_with_logging").setLevel(logging.WARNING)
Another option (though not recommended if the generic method above works) is to extract the module's logger variable and customize it to your needs. Most third-party modules store it in a module-level variable called logger or _log. In your case:
import logging
import pymisp
pymisp.logger.setLevel(logging.INFO)
# code of module goes here
A colleague of mine helped with this question:
Get a named logger yourLogger = logging.getLogger('your_logger')
Add a filter to each handler prevents them to print/save other logs than yours
for handler in logging.root.handlers:
handler.addFilter(logging.Filter('your_logger'))
I am working with a python script, and i face importing problem when i try to import a class from another python script. Here is how my python project folder looks:
Mysql_Main/
checks.py
Analyzer/
config.py
ip.py
op.py
__init__.py
Now i want to import two classes named: Config() and Sqlite() from config.py into the checks.py script.How do i do it?
This is what i tried, but its resulting in an error!
inside checks.py:
from Analyzer import config
config = config.Config()
sqlite = config.Sqlite()
The problem is that Config class is imported properly, but Sqlite class is not getting imported.It is showing error - Config instance has no attribute 'Sqlite'
When you do:
config = config.Config()
You write over the variable config and it no longer points to the module config. It stores the new Config instance.
Try:
from Analyzer import config
config_instance = config.Config()
sqlite_instance = config.Sqlite()
I used to Python logging, it works fine. The logging.basicConfig(...) set in one module (a some.py file), then we can use logging every where. Obviously, logging is global.
The question is how logging find it's settings, when we not call the module where basicConfig(...) appeared (in some.py file )? Is logging scan all the packages?
Even the logging.basicConfig(...) put into an any.py and the module (any.py) never get imported, or not used anywhere, the logging setting take effect!
To understand logging you have dive into Python's standard library sources.
Here is the trick:
#/usr/lib/python3.2/logging/__init__.py
...
root = RootLogger(WARNING)
Logger.root = root
Logger.manager = Manager(Logger.root)
...
# and
def basicConfig(**kwargs):
...
hdlr = StreamHandler(stream)
fs = kwargs.get("format", BASIC_FORMAT)
dfs = kwargs.get("datefmt", None)
style = kwargs.get("style", '%')
fmt = Formatter(fs, dfs, style)
hdlr.setFormatter(fmt)
root.addHandler(hdlr)
So, when you call basicconfig() with certain parameters, root logger is set.
Finally getLogger:
def getLogger(name=None):
"""
Return a logger with the specified name, creating it if necessary.
If no name is specified, return the root logger.
"""
if name:
return Logger.manager.getLogger(name)
else:
return root
I think there is no magic scanning here.
Try to test it this way in a separate test directory:
test/main.py:
import logging
logging.info('test')
test/any.py:
import logging
logging.basicConfig(filename='test.log', level=logging.INFO)
python main.py
Result: NO test.log file.
Now let's update the test:
test/main.py:
import logging
import any
logging.info('test')
python main.py
Result: new test.log file with INFO:root:test string inside.
So I guess that any.py in your case is imported somehow,
despite your expectations.
You may find the way any.py is imported easily,
just add few lines there:
test/any.py:
from traceback import print_stack
print_stack()
...
python main.py
Result:
File "main.py", line 2, in
import any
File "any.py", line 2, in
print_stack()
This stack shows that any.py is imported from main.py.
I hope you will find where it is imported from in your case.