Run Python Script at OS X Startup

Here's the full solution I am using on Mojave:

Plist: ~/Library/LaunchAgents/play.with.mpv.plist

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
    <key>Disabled</key>
    <false/>
    <key>EnvironmentVariables</key>
    <dict>
        <key>PATH</key>
        <string>/Users/e/Library/Python/3.7/bin:/usr/local/bin</string>
    </dict>
    <key>KeepAlive</key>
    <true/>
    <key>Label</key>
    <string>play.with.mpv</string>
    <key>ProgramArguments</key>
    <array>
        <string>/usr/local/bin/python3</string>
        <string>/Users/e/Library/Python/3.7/bin/play-with-mpv</string>
    </array>
    <key>RunAtLoad</key>
    <true/>
    <key>StandardErrorPath</key>
    <string>/tmp/play.with.mpv.stderr</string>
    <key>StandardOutPath</key>
    <string>/tmp/play.with.mpv.stdout</string>
</dict>
</plist>

Mind the PATH to python3 - find it with which python3 and the play-with-mpv python script!

Load plist:

launchctl load ~/Library/LaunchAgents/play.with.mpv.plist

If your video is dropping frames as hell, create mpv config in ~/.config/mpv/mpv.conf and put there this:

video-sync=display-resample

if that do doesn't help, try this instead

opengl-early-flush=no

Adapt the following accordingly, name it something like myscript_launcher.plist, and put it in either one of three locations: /System/Library/LaunchAgents, /System/Library/LaunchDaemons, /Users/<username>/Library/LaunchAgents.

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
    <key>Label</key>
    <string>my.python.script.name</string>
    <key>ProgramArguments</key>
    <array>
        <string>/path/to/python</string>
        <string>/path/to/python/script.py</string>
    </array>
    <key>StandardErrorPath</key>
    <string>/var/log/python_script.error</string>
    <key>KeepAlive</key>
    <true/>
</dict>
</plist>

Also, let's assume you put the plist file in ~/Library/LaunchAgents. You can start and stop it with the launchctl. To start, use launchctl load ~/Library/LaunchAgents/myscript_launcher.plist. To stop it, do the same but use the unload argument

You need to create a shell file that launches your python code. Tell the shell script to start at log in.

example

#!/bin/bash
python username/Desktop/startupscripts/file.py

save the file with the .sh extension.

add the .sh file to "System Preference -> Users and Groups -> Login items", the .sh script will call the python file.

This is what you should have in the shell file. I'm assume this is the path to the file, if it isn't modify it.

#!/bin/bash
python /Users/username/moviebuzz-api/flask/bin/streaming_movies.py

nothing else.