How to set up relative paths to make a portable .exe build in PyInstaller with Python 3?

Question

I've looked up everywhere and got no definite response to a rather trivial question.

I have a Python project in PyCharm on Windows 7 that contains multiple .py files (which are connected via "from %package_name%.%script_name% import %class_name%") and a folder inside the project with two simple text files. I've installed PyInstaller 3.6 into project's venv and use it as an external tool, that points to a .spec file. So far, so good. The .spec file is as follows:

# -*- mode: python ; coding: utf-8 -*-

block_cipher = None


a = Analysis(['C:\\Users\\%username%\\PycharmProjects\\%project_folder%\\%project_folder%\\main.py'],
             pathex=['C:\\Users\\%username%\\PycharmProjects\\%project_folder%\\%project_folder%'],
             binaries=[],
             datas=[('txt_files\\file1.txt', '.'), ('txt_files\\file2.txt', '.')],
             hiddenimports=[],
             hookspath=[],
             runtime_hooks=[],
             excludes=[],
             win_no_prefer_redirects=False,
             win_private_assemblies=False,
             cipher=block_cipher,
             noarchive=False)
a.datas += [
    ("C:\\Users\\%username%\\PycharmProjects\\%project_folder%\\%project_folder%\\txt_files\\file1.txt","txt_files\\file1.txt","DATA"),
    ("C:\\Users\\%username%\\PycharmProjects\\%project_folder%\\%project_folder%\\txt_files\\file2.txt","txt_files\\file2.txt","DATA"),
]
pyz = PYZ(a.pure, a.zipped_data,
             cipher=block_cipher)
exe = EXE(pyz,
          a.scripts,
          [],
          exclude_binaries=True,
          name='%project_name%',
          debug=False,
          bootloader_ignore_signals=False,
          strip=False,
          upx=True,
          console=True )
coll = COLLECT(exe,
               a.binaries,
               a.zipfiles,
               a.datas,
               strip=False,
               upx=True,
               upx_exclude=[],
               name='%project_name%')

The problem is that if I hard-code the absolute paths to the bundled .txt files in the scripts themselves, the app compiles and has no run-time errors. However, if I use relative paths inside the scripts, the app compiles, but gives a run-time error, that a .txt file (i.e. file1.txt) is not found INSIDE the /build (or /dist, I may be wrong here) directory (which is obviously not there).

Of course, hard-coding the absolute paths is a bad practice, especially, when talking not only about portability to another machine, but also making the app cross-platform. I know that the build process may depend on sys._MEIPASS, but I don't know exactly how to use it in my context.

In which script (main, .spec or other?) shall I put the part that gets the absolute path to a bundled file using sys._MEIPASS? And how should this code part look like on Python 3.7? I've seen different answers (i.e. this one) and already tried them, but none seemed to work in my case.

Answer 1

Using --onefile bundles all the datas together into the .exe file.

When you execute the file, these files are "unpacked" to a temporary file location. On Windows, this is usually C:\Users\<You>\AppData\Local\Temp\MEIxxx.

So, when you are developing your script, the data files (your text files in this example) will be located at

C:\\Users\\%username%\\PycharmProjects\\%project_folder%\\%project_folder%\txt_files\

but when the app is compiled, they will be extracted to the temporary directory mentioned above. So you need a way to tell the script whether you are developing, or it has been compiled. This is where you can use the 'frozen' flag (see the docs here)

An approach I have used before, is to create a utility function like this

def resolve_path(path):
    if getattr(sys, "frozen", False):
        # If the 'frozen' flag is set, we are in bundled-app mode!
        resolved_path = os.path.abspath(os.path.join(sys._MEIPASS, path))
    else:
        # Normal development mode. Use os.getcwd() or __file__ as appropriate in your case...
        resolved_path = os.path.abspath(os.path.join(os.getcwd(), path))

    return resolved_path

Then whenever you want to use a path in your script, for example accessing your text files you can do

with open(resolve_path("txt_files/file1.txt"), "r") as txt:
    ...

which should resolve the correct path whichever mode you are in.

A note on your .spec file

1. You don't have to specify all the text files individually. You can of course, and you may have a good reason for doing so which is fine. But you could do

datas=[('txt_files', '.')]

which puts the contents of txt_files directory in the root of your bundle. Be careful with this however, because now the paths to your text files will be <dev directory>\txt_files\file1.txt but in the bundled app, they will be <MEIPASS directory>\file1.txt. You may want to keep the 'relative' part of the path the same by doing

datas=[('txt_files', 'txt_files')]

which will mirror the file structure between your development folder and your bundled app.

2. Also consider if you build with the spec file, remove the COLLECT part in order to produce a onefile bundled executable.

Answer 2

I have the following FS

• GitRepoForMySomeProject
  • MySomeProject
    • main.py
  • MyGitSubmodule
  • ExeSettings.spec
  • ExeVersion.py
  • ExeMySomeProject.bat ("pyinstaller ExeSettings.spec")

In main.py are using some submodule which placed into subfolder "MyGitSubmodule/ReportGenerator.py"

from MyGitSubmodule import ReportGenerator as _report_

Here is my ExeSettings.spec file, with relative path pathex=['../MySomeProject']

# -*- mode: python -*-

block_cipher = None


a = Analysis(['MySomeProject/main.py'],
             pathex=['../MySomeProject'],
             binaries=[],
             datas=[],
             hiddenimports=[],
             hookspath=[],
             runtime_hooks=[],
             excludes=[],
             win_no_prefer_redirects=False,
             win_private_assemblies=False,
             cipher=block_cipher)
pyz = PYZ(a.pure, a.zipped_data,
             cipher=block_cipher)
exe = EXE(pyz,
          a.scripts,
          a.binaries,
          a.zipfiles,
          a.datas,
          name='MySomeProject',
          debug=False,
          strip=False,
          upx=True,
          console=False,
          icon='my.ico',
          version='ExeVersion.py')

if forget to add this path, we will have

ModuleNotFoundError: No module named "MyGitSubmodule"