help: add config to hide server host from help listing

Adds a config section to help.py that has a setting to show the server host
in the first line of a full help listing. Defaults to true. Additionally
implements cache validation accounting for changes to config during runtime.

sopel/modules/help.py

@@ -18,12 +18,10 @@
 
 import requests
 
+from sopel.config.types import ChoiceAttribute, ValidatedAttribute, StaticSection
 from sopel.logger import get_logger
 from sopel.module import commands, rule, example, priority
-from sopel.config.types import (
-    StaticSection, ChoiceAttribute
-)
-
+from sopel.tools import SopelMemory
 
 LOGGER = get_logger(__name__)
 
@@ -136,13 +134,17 @@ def post_to_termbin(msg):
     'termbin': post_to_termbin,
 }
 
+HELP_CACHE_NAMESPACE = 'help-setting-cache'  # Set top-level memory key name
+
 
 class HelpSection(StaticSection):
     """Configuration section for this module."""
     output = ChoiceAttribute('output',
                              list(PASTEBIN_PROVIDERS),
                              default='clbin')
     """The pastebin provider to use for help output."""
+    show_server_host = ValidatedAttribute('show_server_host', bool, default=True)
+    """Show the IRC server's hostname/IP in the first line of the help listing?"""
 
 
 def configure(config):
@@ -152,14 +154,59 @@ def configure(config):
         'output',
         'Pick a pastebin provider: {}: '.format(provider_list)
     )
+    config.help.configure_setting(
+        'show_server_host',
+        'Should the help command show the IRC server\'s hostname/IP in the listing?'
+    )
 
 
 def setup(bot):
-    global help_prefix
+    global help_prefix, help_track_settings
+
+    bot.config.define_section('help', HelpSection)
+
+    # Put name of settings that should be tracked in cache validation in
+    # 'help-track-settings' dict below; i.e., those that will require the help
+    # listing to be regenerated, or re-POSTed to paste.
+    # Keys are module names, and values are lists containing setting names
+    # specific to that module; e.g. for this (help.py) module
+    # [help]
+    # show_server_host = ...
+    help_track_settings = {
+        'help': [
+            'output',
+            'show_server_host',
+        ]
+    }
+
+    # Initialize memory
+    if not bot.memory.contains(HELP_CACHE_NAMESPACE):
+        bot.memory[HELP_CACHE_NAMESPACE] = SopelMemory()
+
+    for section in help_track_settings:
+        if section not in bot.memory[HELP_CACHE_NAMESPACE]:
+            bot.memory[HELP_CACHE_NAMESPACE][section] = SopelMemory()
+
+    update_cache(bot)  # Initialize cache with first call
+
     help_prefix = bot.config.core.help_prefix
     bot.config.define_section('help', HelpSection)
 
 
+def update_cache(bot):
+    for section, setting_names_list in help_track_settings.iteritems():
+        for setting_name in setting_names_list:
+            bot.memory[HELP_CACHE_NAMESPACE][section][setting_name] = getattr(getattr(bot.config, section), setting_name)
+
+
+def is_cache_valid(bot):
+    for section, setting_names_list in help_track_settings.iteritems():
+        for setting_name in setting_names_list:
+            if bot.memory[HELP_CACHE_NAMESPACE][section][setting_name] != getattr(getattr(bot.config, section), setting_name):
+                return False
+    return True
+
+
 @rule('$nick' r'(?i)(help|doc) +([A-Za-z]+)(?:\?+)?$')
 @example('.help tell')
 @commands('help', 'commands')
@@ -196,11 +243,7 @@ def msgfun(l):
         # actually creating the list first. Maybe worth storing the link and a
         # heuristic in the DB, too, so it persists across restarts. Would need a
         # command to regenerate, too...
-        if (
-                'command-list' in bot.memory and
-                bot.memory['command-list'][0] == len(bot.command_groups) and
-                bot.memory['command-list'][2] == bot.config.help.output
-        ):
+        if 'command-list' in bot.memory and bot.memory['command-list'][0] == len(bot.command_groups) and is_cache_valid(bot):
             url = bot.memory['command-list'][1]
         else:
             bot.say("Hang on, I'm creating a list.")
@@ -219,9 +262,8 @@ def msgfun(l):
             url = create_list(bot, '\n\n'.join(msgs))
             if not url:
                 return
-            bot.memory['command-list'] = (len(bot.command_groups),
-                                          url,
-                                          bot.config.help.output)
+            bot.memory['command-list'] = (len(bot.command_groups), url)
+            update_cache(bot)
         bot.say("I've posted a list of my commands at {0} - You can see "
                 "more info about any of these commands by doing {1}help "
                 "<command> (e.g. {1}help time)".format(url, help_prefix))
@@ -232,7 +274,7 @@ def create_list(bot, msg):
 
     Returns the URL from the chosen pastebin provider.
     """
-    msg = 'Command listing for {}@{}\n\n'.format(bot.nick, bot.config.core.host) + msg
+    msg = 'Command listing for {}{}\n\n'.format(bot.nick, ('@' + bot.config.core.host) if bot.config.help.show_server_host else '') + msg
 
     try:
         result = PASTEBIN_PROVIDERS[bot.config.help.output](msg)