Repair paths used for Python imports and ArcPy DLLs before importing ArcPy. Fixes issues where ArcPy in Python 2.7 is used to call a Python 3 script with ArcPy.

Fix_Python3_ArcPy_Paths.py

import sys, os

# FIX PATHS FOR IMPORTS & DLL WHEN RUNNING ON SERVER
# (otherwise, it will try to load ArcPy from the Python 2.7 libraries when called via ArcGIS Server)
if ("\\Server\\framework\\runtime\\" in sys.executable):
    # Get installation base (e.g. C:\Program Files\ArcGIS)
    base = sys.executable.rsplit("\\Server\\", 1)[0]
    baseLower = base.lower()

    # Remove invalid python import paths
    for p in sys.path.copy():
        pl = p.lower()
        if pl.startswith(baseLower) and not "\\framework\\runtime\\" in pl:
            sys.path.remove(p)
        if "\\desktop10." in pl:
            sys.path.remove(p)

    # Correct DLL Loading Paths
    try:
        import win32api
    except ModuleNotFoundError:
        message = "Required module pywin32 not found. Install on server using following command: \""
        pipPath = os.path.join(os.path.dirname(sys.executable), "Scripts\pip")
        printOutput(None, message + pipPath + "\" install pywin32", None)
        exit()

    win32api.SetDllDirectory(os.path.join(base, "Server\\bin"))
    win32api.SetDllDirectory(os.path.join(base, "Server\\framework\\runtime\\ArcGIS\\bin"))
    win32api.SetDllDirectory(os.path.join(base, "Server\\framework\\runtime\\ArcGIS\\bin\\Python\\envs\\arcgispro-py3"))