Python: How to create dependencies in repos in python projects? - python

I am a python beginner, I have Project One which has all the code in a git repo, I am starting a few new projects with their own repos which will all use the generic code in Project One, I don't want to copy paste code. What I am hoping to achieve is separate out the generic code from Project One so it can be inherited/imported in different projects.
generic_Code
-fileOne.py
-fileTwo.py
repo two
Project One
-fileA.py
-fileB.py
repo three
ProjectTwo
-fileC.py
-fileD.py
The goal is I should be able to import classes from Generic_Code repo into files in project one and two. I am using Pycharm and a mac system. On Pycharm, I attached the three projects together and made projectone and two have dependencies to the Generic project, which seem to work but not sure if this is the right way.
Also read something about setup.py but not sure what that is.

Related

Correct way to develop a python package at same time than application

I'm developing an application, it is in an early stage.
At the same time I've started another project that will need some files form the first one, so now the point is to extract that files to a package that I will use from both projects.
Both projects are under git. so "linking" doesn't look a good idea.
The common functions are in an early stage, that means a lot of changes in the near future.
I think that the best solution is to extract common code to a new repository as package but I don't know what is the most productive way to do that.
If I do a package and install it, every change will need an installation, so debugging could be so tedious.
Which is most common or recommended way to do that?
You can use Git Submodules for this purpose. You include your library inside your main project.
git submodule add git#guthub.com:your-library.git
This command creates .gitmodule with your confuguration and adds your-library folder with library's code. You can commit changes to your-library just from this new folder.
cd your-library
touch new-file.txt
git add .
git commit -m "changes"
git push
Also you can pull changes for library
cd your-library
git pull

How do I make a macOS app out of my Python program?

I've made this question because I had to go through the whole process of creating my own application using Apple's somewhat lacking documentation, and without the use of py2app. I wanted to create the whole application structure so I know exactly what was inside, as well as create an installer for it. The latter of these is still a mystery, so any additional answers with information on making a custom installer would be appreciated. As far as the actual "bundle" structure goes, however, I think I've managed to get the basics down. See the answer below.
Edit: A tutorial has been linked at the end of this answer on using PyInstaller; I don't know how much it helps as I haven't used it yet, but I have yet to figure out how to make a standalone Python application without the use of a tool like this and it may just be what you're looking for if you wish to distribute your application without relying on users knowing how to navigate their Python installations.
A generic application is really just a directory with a .app extension. So, in order to build your application, just make the folder without the extension first. You can rename it later when you're finished putting it all together. Inside this main folder will be a Contents folder, which will hold everything your application needs. Finally, inside Contents, you will place a few things:
Info.plist
MacOS
Resources
Frameworks
Here you can find some information on how to write your Info.plist file. Basically, this is where you detail information about your application.
Inside the MacOS you want to place your main executable. I'm not sure that it matters how you write it; at first, I just had a shell script that called python3 ./../Resources/MyApp.py. I didn't think this was very neat though, so eventually I called the GUI from a Python script which became my executable (I used Tkinter to build my application's GUI, and I wrote several modules which I will get to later). So now, my executable was a Python script with a shebang pointing to the Python framework in my application's Frameworks folder, and this script just created an instance of my custom Tk() subclass and ran the mainloop. Both methods worked, though, so unless someone points out a reason to choose one method over the other, feel free to pick. The one thing that I believe is necessary, is that you name your executable the SAME as your application (before adding the .app). That, I believe, is the only way that MacOS knows to use that file as your application's executable. Here is a source that describes the bundle structure in more detail; it's not a necessary read unless you really want to get into it.
In order to make your executable run smoothly, you want to make sure you know where your Python installation is. If you're like me, the first thing you tried doing on your new Mac was open up Terminal and type in python3. If this is the case, this prompted you to install the Xcode Command Line tools, which include an installation of Python 3.8.2 (most recent on Xcode 12). Then, this Python installation would be located at /usr/bin/python3, although it's actually using the Python framework located at
/Applications/Xcode.app/Developer/Library/Frameworks/Python3.framework/Versions/3.8/bin/python3
I believe, but am NOT CERTAIN, that you could simply make a copy of this framework and add it to your Frameworks folder in order to make the app portable. Make a copy of the Python3.framework folder, and add it to your app's Frameworks folder. A quick side note to be wary of; Xcode comes packaged with a lot of useful tools. In my current progress, the tool I am most hurting for is the Fortran compiler (that I believe comes as a part of GCC), which comes with Xcode. I need this to build SciPy with pip install scipy. I'm sure this is not the only package that would require tools that Xcode provides, but SciPy is a pretty popular package and I am currently facing this limitation. I think by copying the Python framework you still lose some of the symlinks that point to Xcode tools, so any additional input on this would be great.
In any case, locate the Python framework that you use to develop your programs, and copy it into the Frameworks folder.
Finally, the Resources folder. Here, place any modules that you wrote for your Python app. You also want to put your application's icon file here. Just make sure you indicate the name of the icon file, with extension, in the Info.plist file. Also, make sure that your executable knows how to access any modules you place in here. You can achieve this with
import os
os.chdir('./../Resources')
import MyModules
Finally, make sure that any dependencies your application requires are located in the Python framework site-packages. These will be located in Frameworks/Python3.framework/Versions/3.X.Y/lib/python3.x.y/site-packages/. If you call this specific installation of Python from the command line, you can use path/to/application/python3 -m pip install package and it should place the packages in the correct folder.
P.S. As far as building the installer for this application, there are a few more steps needed before your application is readily downloaded. For instance, I believe you need to use the codesign tool in order to approve your application for MacOS Gatekeeper. This requires having a developer license and manipulating certificates, which I'm not familiar with. You can still distribute the app, but anyone who downloads it will have to bypass the security features manually and it will seem a bit sketchy. If you're ready to build the installer (.pkg) file, take a look at the docs for productbuild; I used it and it works, but I don't yet know how to create custom steps and descriptions in the installer.
Additional resources:
A somewhat more detailed guide to the anatomy of a macOS app
A guide I found, but didn't use, on using codesign to get your app past Gatekeeper
A RealPython tutorial I found on using PyInstaller to build Python-based applications for all platforms

Python:Sharing codes of models between 2 modules

I'm climbing my learning curve in Python and try to understand where to put everything.
I originally have a python module in a folder and then a sub folder src, in this src folder I will then have my main source files say main.py then I will have models folder storing my models codes.
/myproject/src/main.py
/myproject/src/models/a-model.py
/myproject/src/models/b-model.py
So my main will import the model like this:
from models.a-model import a
Then when I package the zip file I just zip the myproject folder with that folder structure and deploy and everything is fine.
Now I have another new module doing something different but need to use the same models.
I can easily duplicate them all and code separately and deploy. But I would like to share the codes to the models, so that when one model changes, I only need to update once, instead of 2 places.
My new module is like
/mynew/src/main-b.py
/mynew/src/models/a-model.py
/mynew/src/models/b-model.py
What is the best practise to do this?
Do I put like this?
/myproject/src/main.py
/mynew/src/main-b.py
/models/a-model.py
/models/b-model.py
And then update the import?
But I have doubt how do I deploy? Do I also have to setup the same folder structures?
One would be adding /myproject/src/models to the environment variable PYTHONPATH. Python adds the directories listed in PYTHONPATH environment variable to sys.path, the list of directories where Python searches when you try to import something. This is bad, because modifying PYTHONPATH has its own side effects, fortunately, virtual environments provide a way to get around those side effects.
Alternatively and much better you could add your modules to site-packages directory, site-packages is added to sys.pathby default, this obviates the need to modifyPYTHONPATH. To locate thesite-packages` directory, refer to this page from Python Documentation: Installing Python Modules (Legacy version).
You could also use LiClipse IDE which comes with Pydev already installed. Create source a folder from the IDE and link your previous project with your newer project. When you link your projects the IDE adds the source folders of your older project to the PYTHONPATH of your newer project and thus Python will be able to locate your modules.

Using Sphinx to document multiple Python projects

I've read a few Sphinx tutorials but I'm still a bit hung up on how I set up multiple projects.
What I mean is, after installing Sphinx, this guide says
To get started, cd into the documentation directory and type: $ sphinx-quickstart
Let's say I have 5 separate Python projects each in it's own directory (all individual git repos, etc).
My question is, what exactly is "the documentation directory" (aside from the obvious) and how do I set up Sphinx when working with multiple projects?
Do I make one "master documentation directory" somewhere and as I use Sphinx, do I create sub directories for each project or similar?
Or do I create a "documentation directory" inside of each of my projects and run $ sphinx-quickstart to set up Sphinx for each individual project?
I'm trying to understand the big picture here but can't find a tutorial that spells out this aspect of things.
The sphinx-quickstart command generates a documentation skeleton for a single project, so if you have multiple separate projects you will have to run it in each one of them. The link you posted uses the phrase "documentation directory" because the directory name and relative position in the project directory is up to you (they appear to be putting it in project_root/doc), not because there should be some centralised directory of documentation for all of your projects.

Python: Is it possible to create a package out of multiple external libraries?

This issue has been driving me insane for the past few days.
So basically, I'm trying to port over a Pure Python project to a proper PyCharm project. This is to basically improve code quality and project structure.
I wish it was as simple as basically creating a virtualenv to house everything, but it isn't. This project will eventually be developed simultaneously by multiple developers with Git as source control, and the default libraries will be modified. I presume this means that the libraries should ideally be tracked by Git in the end. Virtualenv shouldn't help here as far as I know because it's not portable between systems (or at least that's still being tested).
This project will also be, in the future, deployed to a Centos server.
So the only plan I can think of to successfully pull off this would be to simply bring in all of the libraries (which was done using pip install -t Libraries <ExampleLibrary>) into a single folder, with a __init__.py inside, and use them from other python files as a package within the Pycharm project.
Is this possible / recommended? I tried various methods to reference these libraries, but they all don't work during runtime. Somehow when the files in the library import something else from their own package, an ImportError is raised saying that there's no such module.
Will accept any other suggestions too.
Using Pycharm Community Edition.
EDIT: After having a good night's rest I think the crux of the issue is really just project organization. Before I ported it over to Pycharm the project worked as expected, but this had all of the python files in the root directory, and the libraries in a subfolder of the root, with every project file having the same boilerplate code:
import os, sys
absFilePath = os.path.dirname(os.path.abspath(__file__));
sys.path.insert(1, absFilePath + "/lib")
I was hoping that by using Pycharm to help me flesh out the packages, I could avoid having repeated boilerplate code.
Note: Not full solution.
The addition of the template code below forces the file containing the code to be in the same directory as the libs folder.
For Pycharm, all I had to do was mark the libs folder as a source folder. Even with the addition of the template code to the file, the modified libraries still work as expected.
For the Python Shell, this template code is still needed:
import os
import sys
absFilePath = os.path.dirname(os.path.abspath(__file__))
sys.path.insert(1, absFilePath + "/lib")

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