Make it easier to set calibre environment variables on macOS

bypy/macos/site.py

@@ -121,12 +121,36 @@ def run_entry_point():
     return getattr(pmod, func)()
 
 
+def read_user_env_vars():
+    try:
+        with open(os.path.expanduser('~/Library/Preferences/calibre/macos-env.txt'), 'rb') as f:
+            raw = f.read().decode('utf-8', 'replace')
+    except EnvironmentError as err:
+        return
+    for line in raw.splitlines():
+        if line.startswith('#'):
+            continue
+        parts = line.split('=', 1)
+        if len(parts) == 2:
+            key, val = parts
+            os.environ[key] = os.path.expandvars(os.path.expanduser(val))
+
+
 def add_calibre_vars(base):
     sys.frameworks_dir = os.path.join(os.path.dirname(base), 'Frameworks')
     sys.resources_location = os.path.abspath(os.path.join(base, 'resources'))
     sys.extensions_location = os.path.join(sys.frameworks_dir, 'plugins')
     sys.binaries_path = os.path.join(os.path.dirname(base), 'MacOS')
 
+    try:
+        read_user_env_vars()
+    except Exception as err:
+        try:
+            sys.stderr.write('Failed to read user env vars with error: {}\n'.format(err))
+            sys.stderr.flush()
+        except Exception:
+            pass
+
     dv = os.environ.get('CALIBRE_DEVELOP_FROM', None)
     if dv and os.path.exists(dv):
         sys.path.insert(0, os.path.abspath(dv))

manual/customize.rst

@@ -43,10 +43,16 @@ Environment variables
     * ``CALIBRE_USE_DARK_PALETTE`` - Set it to ``1`` to have calibre use dark colors and ``0`` for normal colors (ignored on macOS).
       On Windows 10 in the absence of this variable, the windows system preference for dark colors is used.
     * ``SYSFS_PATH`` - Use if sysfs is mounted somewhere other than /sys
-    * ``http_proxy``, ``https_proxy`` - Used on linux to specify an HTTP(S) proxy
+    * ``http_proxy``, ``https_proxy`` - Used on Linux to specify an HTTP(S) proxy
+
+See `How to set environment variables in Windows <https://www.computerhope.com/issues/ch000549.htm>`_. If you are on macOS
+you can set environment variables by creating the :file:`~/Library/Preferences/calibre/macos-env.txt` and putting
+the environment variables one per line in it, for example::
+
+    CALIBRE_DEVELOP_FROM=$HOME/calibre-src/src
+    CALIBRE_NO_NATIVE_FILEDIALOGS=1
+    CALIBRE_CONFIG_DIRECTORY=~/.config/calibre
 
-See `How to set environment variables in Windows <https://www.computerhope.com/issues/ch000549.htm>`_ or
-`How to set environment variables in macOS <https://www.dowdandassociates.com/blog/content/howto-set-an-environment-variable-in-mac-os-x-launchd-plist/>`_.
 
 Tweaks
 ------------