Image taken from Sqreen.io It’s been almost an year since I have been a maintainer for , a cross-platform multi-lingual desktop app, that allows you to tag your music files via this . MusicBrainz Picard very cool service called MusicBrainz Picard, I’d say is a fairly large python app with about ~35k SLoC. With a python app of such size, come challenges. One of the toughest challenges I faced this last year has been packaging Picard for all the three platforms that it supports, Linux, macOS and Windows after I ported it to Python 3/PyQt5 for my GSoC project. You can read more about that here. “Freezing” your code is creating an executable file to distribute to end-users, that contains all of your application code as well as the Python interpreter. The advantage of distributing this way is that your application will “just work”, even if the user doesn’t already have the required version of Python (or any) installed. On Windows, and even on many Linux distributions and OS X, the right version of Python will not already be installed. - Hitchhiker’s Guide to Python Testing my options Our existing setup used py2exe and py2app to freeze Picard for Windows and macOS respectively. Since they don’t entirely support Python 3 and PyQt5, I was on the lookout for a new freezing tool. I finally settled on after testing waters with . PyInstaller cx_Freeze PyInstaller — A happy surprise One thing I’d like to say about PyInstaller — I was absolutely surprised how easy it was to freeze my python application, while putting minimal efforts from my side, chasing mythical dependencies. It supports Python 2 and 3 and all 3 desktop OSes and even allows you to create portable all-in-one binaries for each. How cool is that! I plan on giving you a small glimpse of how powerful and simple PyInstaller is, and how, coupled with and , you can package your python apps for Windows and macOS without even having access to either of them. AppVeyor TravisCI Getting started In this part of the blog, we will be making a PyInstaller spec file and freezing our package. In the next part, we will be looking into TravisCI and AppVeyor for continuous delivery. Installing PyInstaller All you need to do is . It is as simple as that. You can either install it globally or in a virtual environment housing your project. The latter is obviously preferable. This will give you access to mainly 2 scripts that we will be using in the rest of this tutorial — and . pip install pyinstaller pyinstaller pyi-makespec Project info and structure Let’s start with a very basic structure to introduce PyInstaller and make adjustments from there on, as per our needs. package_dir├── package│   ├── submodule_bar│   ├── submodule_foo│   ├── __init__.py│   └── main.py├── entry_point.py└── setup.py The above assume that you have an entry point script called which launches your application. See for help on how to package your app. entry_point.py python-packaging Now comes the magical part. All you need to do to freeze your app is pyinstaller entry_point.py -n foobar It is as simple as that! PyInstaller will automagically figure out all the dependencies, include all the dynamic libraries that need to be loaded and create a directory with the frozen app named . dist **foobar** The output should as follows package_dir├── dist│   └── foobar│       ├── ...│       ├── ...│       ├── ...│       └── foobar├── package│   ├── submodule_bar│   ├── submodule_foo│   ├── __init__.py│   └── main.py├── entry_point.py├── foobar.spec└── setup.py You can execute your app by launching (Of course it will be or on Windows and macOS respectively. dist/foobar/foobar foobar.exe foobar.app Portable apps, what is this magic? Now let’s take things a bit further. What if you want you entire app bundled with all its dependencies as a single portable executable? Simple, just pass the flag to PyInstaller. --onefile pyinstaller entry_point.py -n foobar --onefile PyInstaller will output a single portable executable in the dist folder named which can easily be launched. Again, PyInstaller will automagically find and bundle all the dependencies inside that one file! foobar It can’t surely be that simple? Can it? What if I need to… Bundle Libraries PyInstaller supports a lot of major frameworks and libraries out of the box. This includes — Babel, Django, IPython, matplotlib, numpy, pillow, PyGTK, PyQt4, PyQt5, scipy, sphinx, SQLAlchemy, wxPython and many more. If your app depends on any of the above libraries, you don’t need to worry about the hassles of including dependent libraries, dlls, hidden imports, packages or anything else for that matter. PyInstaller takes care of everything for you. It inspects your code recursively and figures out all the dependencies. Add and bundle resources Resources can be anything, images, icons, textual data, translation strings. There is a very simple recipe to bundle and access your resources. For simplicity, let’s assume all your resources are available inside a directory called as below — resources package_dir├── package│   ├── submodule_bar│   ├── submodule_foo│   ├── __init__.py│   └── main.py├── resources│   ├── bar.dat│   └── foo.png├── entry_point.py└── setup.py Bundling the resources Run . The script accepts the same arguments as but instead of actually running PyInstaller, it creates a spec file for you to customise, which can then be called with . pyi-makespec entry_point.py -n foobar --onefile pyi-makespec pyinstaller foobar.spec pyinstaller foobar.spec Your file should look something like this — foobar.spec The spec file is simply a python script albeit with some special callables as shown above. To add resources, you simply need to create an array with a list of tuples — The first string specifies the file or files as they are in this system now. The second specifies the name of the to contain the files at run-time. folder A simple script to do the same would be — You will be adding the above code to the spec file, which should now look like this — Notice the call to _get_resources()_ in _a.datas_ . Accessing bundled resources Quoting from the — PyInstaller wiki You may need to learn at run-time whether the app is running from source, or is “frozen” (bundled). For example, you might have data files that are normally found based on a module’s attribute. That will not work when the code is bundled. __file__ The PyInstaller bootloader adds the name to the module. So the test for “are we bundled?” frozen sys To summarise, this is what you need to do to access any resources you have bundled — Add the following two variables to your utility section — You can then use this in your as follows — entry_point.py You can now load your resources in as follows — main.py Bundle binaries PyInstaller should automagically bundle any or files by inspecting your python module. But in case it it is easy to add them. .so .dll fails to do so, Bundling binaries or libraries that your app depends on is pretty much similar to how you would bundle data files. Assuming the following directory structure — package_dir├── bin│   ├── bar.so│   ├── bar.dll│   └── bar.dylib├── package│   ├── submodule_bar│   ├── submodule_foo│   ├── __init__.py│   └── main.py├── resources│   ├── bar.dat│   └── foo.png├── entry_point.py└── setup.py Let’s say your app depends on a shared library , and you have binaries available for it for all 3 operating systems. bar You might go around including them as follows — You might ask, what’s the difference between adding a file as a data file or a binary file, well quoting from the PyInstaller Wiki — Binary files refers to DLLs, dynamic libraries, shared object-files, and such, which PyInstaller is going to search for further binary dependencies. Files like images and PDFs should go into the datas So make sure you are adding any dlls or so files as binaries instead of data files. Freeze a GUI app You will probably want to pass the flag to in order to make sure there is no console while opening the App. --windowed pyinstaller Freeze a macOS app If you are freezing a one-file windowed macOS app you will want to add an additional callable to your spec file like so — See the for more information about these options. PyInstaller-Wiki Note: For simple cases, you can also accomplish all the of the above through flags passed to the or scripts. See for more information. pyisntaller pyi-makespec Using Spec Files What’s next? The above recipes should be more than enough for all general use cases. I hope the above provides a basic guide on how to use PyInstaller. For more advanced use cases, you can sift through the PyInstaller Wiki. If you want to see the above guide in action, you can have a look at the . Picard github repo In the next part of this blog, we will learn how to make use of AppVeyor and TravisCI along with PyInstaller to bundle our applications. HALLLLP, I am stuck! If you find yourself unable to comprehend any part of the guide or have a very particular use-case, leave a comment below, I will be happy to help if I can :)

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The one-stop guide to (easy) cross-platform Python freezing: Part 1

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The one-stop guide to (easy) cross-platform Python freezing: Part 1

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