[#346] Add a skip-steam-check CLI parameter

This should make Ice significantly easier to use on SteamOS, where everything has a `steam` prefix.

Also refactor how the CLI interacts with IceEngine, as I want to stop passing around `options`. To stop doing the parameter duplication between `main` and `run` I extracted the "catch exceptions" functionality into a decorator.

ice/decorators.py

@@ -0,0 +1,13 @@
+# encoding: utf-8
+
+from logs import logger
+
+def catch_exceptions(msg):
+  def decorator(func):
+    def wrapped(*args, **kwargs):
+      try:
+        func(*args, **kwargs)
+      except Exception as e:
+        logger.exception(msg)
+    return wrapped
+  return decorator

ice/runners/command_line_runner.py

@@ -23,6 +23,8 @@ def __init__(self, steam=None, filesystem=None):
   def get_command_line_args(self, argv):
     parser = argparse.ArgumentParser()
     parser.add_argument('pdebug', type=bool, nargs='?', help="Pastes debug logs to pastebin to include with bug reports.")
+    parser.add_argument('-s', '--skip-steam-check', action='store_true', help="Skips checking whether Steam is running")
+    # Config options
     parser.add_argument('-c', '--config', type=str, default=None)
     parser.add_argument('-C', '--consoles', type=str, default=None)
     parser.add_argument('-e', '--emulators', type=str, default=None)
@@ -37,5 +39,14 @@ def run(self, argv):
       debug.paste_debug_logs()
       return
 
-    engine = IceEngine(self.steam, filesystem = self.filesystem, options = options)
-    engine.main(dry_run=options.dry_run)
+    engine = IceEngine(
+      self.steam,
+      filesystem = self.filesystem,
+      file_overrides = {
+        'config': options.config,
+        'consoles': options.consoles,
+        'emulators': options.emulators,
+      })
+    engine.run(
+      skip_steam_check=options.skip_steam_check,
+      dry_run=options.dry_run)

ice/runners/ice_engine.py

@@ -14,6 +14,7 @@
 from ice import backups
 from ice import configuration
 from ice import consoles
+from ice import decorators
 from ice import emulators
 from ice import paths
 from ice import settings
@@ -27,9 +28,18 @@
 from ice.steam_grid_updater import SteamGridUpdater
 from ice.steam_shortcut_synchronizer import SteamShortcutSynchronizer
 
+STEAM_CHECK_SKIPPED_WARNING = """\
+Not checking whether Steam is running. Any changes made may be overwritten \
+when Steam exits.\
+"""
+
 class IceEngine(object):
 
-  def __init__(self, steam, filesystem, options):
+  def __init__(
+    self,
+    steam,
+    filesystem,
+    file_overrides):
     """Valid options for creating an IceEngine are as follows:
 
     * config    - The path to the config file to use. Searches the default paths
@@ -48,9 +58,9 @@ def __init__(self, steam, filesystem, options):
     self.users = filter(is_user_context, steam_module.local_user_contexts(self.steam))
 
     logger.debug("Initializing Ice")
-    self.config    = settings.load_configuration(filesystem, options.config)
-    self.emulators = settings.load_emulators(filesystem, options.emulators)
-    self.consoles  = settings.load_consoles(self.emulators, filesystem, options.consoles)
+    self.config    = settings.load_configuration(filesystem, file_overrides['config'])
+    self.emulators = settings.load_emulators(filesystem, file_overrides['emulators'])
+    self.consoles  = settings.load_consoles(self.emulators, filesystem, file_overrides['consoles'])
 
     parser = ROMParser()
     self.rom_finder = ROMFinder(self.config, filesystem, parser)
@@ -60,13 +70,16 @@ def __init__(self, steam, filesystem, options):
 
     self.grid_updater = SteamGridUpdater(settings.image_provider(self.config))
 
-  def validate_environment(self):
+  def validate_environment(self, skip_steam_check):
     """
     Validate that the current environment meets all of Ice's requirements.
     """
     with EnvironmentChecker(self.filesystem) as env_checker:
-      # If Steam is running then any changes we make will be overwritten
-      env_checker.require_program_not_running("Steam")
+      if not skip_steam_check:
+        # If Steam is running then any changes we make will be overwritten
+        env_checker.require_program_not_running("Steam")
+      else:
+        logger.warning(STEAM_CHECK_SKIPPED_WARNING)
       # I'm not sure if there are situations where this won't exist, but I
       # assume that it does everywhere and better safe than sorry
       env_checker.require_directory_exists(self.steam.userdata_directory)
@@ -90,14 +103,18 @@ def create_backup(self, user, dry_run=False):
     else:
       backups.create_backup_of_shortcuts(self.config, user)
 
-  def run(self, dry_run=False):
+  @decorators.catch_exceptions("An exception occurred while running Ice")
+  def run(
+    self,
+    skip_steam_check=False,
+    dry_run=False):
     if self.steam is None:
       logger.error("Cannot run Ice because Steam doesn't appear to be installed")
       return
 
     logger.info("=========== Starting Ice ===========")
     try:
-      self.validate_environment()
+      self.validate_environment(skip_steam_check)
     except EnvCheckerError as e:
       logger.info("Ice cannot run because of issues with your system.\n")
       logger.info("* %s" % e.message)
@@ -115,12 +132,6 @@ def run(self, dry_run=False):
       self.shortcut_synchronizer.sync_roms_for_user(user, roms, self.consoles, dry_run=dry_run)
       self.grid_updater.update_artwork_for_rom_collection(user, roms, dry_run=dry_run)
 
-  def main(self, dry_run=False):
-    try:
-      self.run(dry_run=dry_run)
-    except Exception as error:
-      logger.exception("An exception occurred while running Ice")
-
 # Logging methods. The purpose of these methods isn't so much to log things as
 # they are to inform the user of the state of their setup (as Ice sees it).
 # They were originally on ice_logging but since they require knowledge of