ios - I can't import Python modules in Xcode 11 using PythonKit

Question

I am now using Swift Package Manager.

Using that, I imported PythonKit into my Swift project.

I can't import the Python modules using the PythonKit now.

It asks me to set the PYTHON_LIBRARY path but I don't know how to do that.

Can anyone help me?

//
//  ViewController.swift
//  VideoStream
//
//  Created by HeRo Gold on 7/20/19.
//  Copyright ? 2019 TopAce. All rights reserved.
//

import UIKit
import PythonKit

let sys = Python.import("sys")

class ViewController: UIViewController {

    @IBOutlet weak var netflixView: WKWebView!
    let netflixURL = URL(string: "https://www.netflix.com/login")

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view.

        let pymsl = try Python.import(name: "pymsl")

        print("Python (sys.version_info.major).(sys.version_info.minor)")
        print("Python Version: (sys.version)")
        print("Python Encoding: (sys.getdefaultencoding().upper())")
    }
}

This is error message when I run the iOS app on my iPhone

Fatal error: Python library not found. Set the PYTHON_LIBRARY environment variable with the path to a Python library.: file /Users/herogold/Library/Developer/Xcode/DerivedData/VideoStream-cjytedddvtktmybclqlztmfdbekk/SourcePackages/checkouts/PythonKit/PythonKit/PythonLibrary.swift, line 40
2019-07-20 23:55:00.967869+0800 VideoStream[31841:170718] Fatal error: Python library not found. Set the PYTHON_LIBRARY environment variable with the path to a Python library.: file /Users/herogold/Library/Developer/Xcode/DerivedData/VideoStream-cjytedddvtktmybclqlztmfdbekk/SourcePackages/checkouts/PythonKit/PythonKit/PythonLibrary.swift, line 40

Answer 1

First SO answer, so please forgive formatting / etc. I suffered through this for a while myself with different errors, but generally same issues. I hope this helps you -- a few resources to consider:

1) Pyto -- a fully embedded Python environment for iOS/Catalyst; with LXML and Python Library porting instructions <-- this is what you need to model after to run on iOS, my solution works for Mac Catalyst (Macs with Python preloaded)

2) Python Kit Tutorial -- this guy goes through, step by step, how to implement PythonKit

Here's what worked for me:

1) Disable App Sandbox in Signing and Capabilities:

In top right corner of App Sandbox, under Signing & Capabilities there is an "X", click that to remove App Sandbox

2) In "Hardened Runtime" under Signing and Capabilities: check "Disable Library Validation"

Image of checkbox for Disable Library Validation

Now, I haven't yet submitted an app to the App Store under these provisions, but at least my python files and libraries load / build / run!

---

UPDATE 05/15/2020:

For Mac Developer Distribution, you will have to sign all .so or .dylib's included with your app, along with the Python Interpreter and bin folder. I made a quick bash script to run through each one when done with dev.

function signThese() {
        find . -name "*.$1" | while read line; do
                codesign --force --verbose=4 --options=runtime --timestamp --sign "Developer ID Application: [INSERT YOUR CERT HERE]" $line
        done
}

This will allow you to use AppSandbox in Signing and Capabilities, and all Hardened Runtime Options (as in not disabling library validation).