Easier and more self documenting patterns for loading/saving Persistent

[python_utils.git] / site_config.py

diff --git a/site_config.py b/site_config.py
index b09e735c79c8f92665438b2c064f9ccf652d33bd..eb7d8845639a6b81b73c22425c90fbc52eb8d5c9 100644 (file)
--- a/site_config.py
+++ b/site_config.py
@@ -1,9 +1,13 @@
 #!/usr/bin/env python3
 
-from dataclasses import dataclass
+# © Copyright 2021-2022, Scott Gasch
+
+"""Location/site dependent data."""
+
 import logging
 import platform
-from typing import Callable
+from dataclasses import dataclass
+from typing import Callable, Optional
 
 # Note: this module is fairly early loaded.  Be aware of dependencies.
 import config
@@ -27,17 +31,39 @@ args.add_argument(
 
 @dataclass
 class SiteConfig(object):
+    """The set of information specific to where the program is running."""
+
     location_name: str
+    """Either "HOUSE" or "CABIN" depending on where we're running"""
+
     location: Location
+    """Same as above but as an enum value instead of a string"""
+
     network: str
+    """The local network specification, e.g. 192.168.0.0/24."""
+
     network_netmask: str
+    """The netmask of the local network, e.g. 255.255.255.0."""
+
     network_router_ip: str
+    """The IP address of the local router, e.g. 192.168.0.1."""
+
     presence_location: Location
+    """Same as location, above."""
+
     is_anyone_present: Callable
+    """Returns a callable which, when invoked, will tell you if it detects
+    any person in your location by auditing network device MAC addresses."""
+
     arper_minimum_device_count: int
+    """How many MAC addresses do we need to see for it to be considered a
+    successful scan?"""
+
+    arper_cache_file: str
+    """The location of the persisted IP-MAC address mappings."""
 
 
-def get_location_name():
+def get_location_name() -> str:
     """
     Where are we?
 
@@ -49,7 +75,7 @@ def get_location_name():
     return get_config().location_name
 
 
-def get_location():
+def get_location() -> Location:
     """
     Returns location as an enum instead of a string.
 
@@ -62,14 +88,83 @@ def get_location():
     return get_config().location
 
 
-def is_anyone_present_wrapper(location: Location):
+def _is_anyone_present_wrapper(location: Location):
     import base_presence
 
     p = base_presence.PresenceDetection()
     return p.is_anyone_in_location_now(location)
 
 
-def get_config():
+def other_location() -> str:
+    """
+    Returns the location where this program is _NOT_ running.
+
+    >>> x = other_location()
+    >>> x in set(['HOUSE', 'CABIN'])
+    True
+
+    >>> y = this_location()
+    >>> x == y
+    False
+
+    """
+    this = this_location()
+    if this == 'HOUSE':
+        return 'CABIN'
+    elif this == 'CABIN':
+        return 'HOUSE'
+    else:
+        raise Exception(f"{this} doesn't tell me where I'm running?!")
+
+
+def this_location() -> str:
+    """
+    Returns the location where this program _IS_ running.
+
+    >>> x = this_location()
+    >>> x in set(['HOUSE', 'CABIN'])
+    True
+
+    """
+    hostname = platform.node()
+    if '.house' in hostname:
+        location = 'HOUSE'
+    elif '.cabin' in hostname:
+        location = 'CABIN'
+    elif '.local' in hostname:
+        location = 'HOUSE'
+    else:
+        raise Exception(f"{hostname} doesn't help me know where I'm running?!")
+    return location
+
+
+def effective_location(location_override: Optional[str] = None) -> str:
+    """Detects and returns a location taking into account two override
+    mechanisms.
+
+    >>> x = effective_location()
+    >>> x in set(['HOUSE', 'CABIN'])
+    True
+
+    >>> effective_location('HOUSE')
+    'HOUSE'
+
+    """
+    if location_override is None:
+        try:
+            location_override = config.config['site_config_override_location']
+        except KeyError:
+            location_override = None
+
+    if location_override is None or location_override == 'NONE':
+        location = this_location()
+    else:
+        logger.debug('site_config\'s location_override was set to: %s', location_override)
+        location = location_override
+    return location
+
+
+def get_config(location_override: Optional[str] = None):
     """
     Get a configuration dataclass with information that is
     site-specific including the current running location.
@@ -79,16 +174,7 @@ def get_config():
     True
 
     """
-    hostname = platform.node()
-    try:
-        location_override = config.config['site_config_override_location']
-    except KeyError:
-        location_override = 'NONE'
-    if location_override == 'NONE':
-        if '.house' in hostname:
-            location = 'HOUSE'
-        elif '.cabin' in hostname:
-            location = 'CABIN'
+    location = effective_location(location_override)
     if location == 'HOUSE':
         return SiteConfig(
             location_name='HOUSE',
@@ -97,8 +183,9 @@ def get_config():
             network_netmask='255.255.255.0',
             network_router_ip='10.0.0.1',
             presence_location=Location.HOUSE,
-            is_anyone_present=lambda x=Location.HOUSE: is_anyone_present_wrapper(x),
+            is_anyone_present=lambda x=Location.HOUSE: _is_anyone_present_wrapper(x),
             arper_minimum_device_count=50,
+            arper_cache_file='/home/scott/cache/.arp_table_cache_house',
         )
     elif location == 'CABIN':
         return SiteConfig(
@@ -108,8 +195,9 @@ def get_config():
             network_netmask='255.255.255.0',
             network_router_ip='192.168.0.1',
             presence_location=Location.CABIN,
-            is_anyone_present=lambda x=Location.CABIN: is_anyone_present_wrapper(x),
+            is_anyone_present=lambda x=Location.CABIN: _is_anyone_present_wrapper(x),
             arper_minimum_device_count=15,
+            arper_cache_file='/home/scott/cache/.arp_table_cache_cabin',
         )
     else:
         raise Exception(f'Unknown site location: {location}')