Make Swarming bot keep 5%+250MB of the disk free.

appengine/swarming/swarming_bot/bot_code/bot_main.py

 # Copyright 2013 The LUCI Authors. All rights reserved.
 # Use of this source code is governed under the Apache License, Version 2.0
 # that can be found in the LICENSE file.
 
 """Swarming bot main process.
 
 This is the program that communicates with the Swarming server, ensures the code
 is always up to date and executes a child process to run tasks and upload
 results back.
 
@@ skipping 234 matching lines @@
 
 
 def is_base_dir_ok(botobj):
   """Returns False if the bot must be quarantined at all cost."""
   if not botobj:
     # This can happen very early in the process lifetime.
     return os.path.dirname(THIS_FILE) != os.path.expanduser('~')
   return botobj.base_dir != os.path.expanduser('~')
 
 
-def get_min_free_space(botobj):
-  """Returns free disk space needed.
-
-  Add a "250 MiB slack space" for logs, temporary files and whatever other leak.
-  """
-  return int(
-      (os_utilities.get_min_free_space(botobj.base_dir) + 250.) * 1024 * 1024)
+def get_desired_free_space(botobj):
+  """Returns free disk space needed (in bytes)."""
+  return int(os_utilities.get_desired_free_space(botobj.base_dir) * 1024 * 1024)
 
 
 def generate_version():
   """Returns the bot's code version."""
   try:
     return zip_package.generate_version()
   except Exception as e:
     return 'Error: %s' % e
 
 
@@ skipping 121 matching lines @@
 
   It will remove unexpected files, remove corrupted files, trim the cache size
   based on the policies and update state.json.
   """
   cmd = [
     sys.executable, THIS_FILE, 'run_isolated',
     '--clean',
     '--log-file', os.path.join(botobj.base_dir, 'logs', 'run_isolated.log'),
     '--cache', os.path.join(botobj.base_dir, 'isolated_cache'),
     '--named-cache-root', os.path.join(botobj.base_dir, 'c'),
-    '--min-free-space', str(get_min_free_space(botobj)),
+    '--min-free-space', str(get_desired_free_space(botobj)),
   ]
   logging.info('Running: %s', cmd)
   try:
     # Intentionally do not use a timeout, it can take a while to hash 50gb but
     # better be safe than sorry.
     proc = subprocess42.Popen(
         cmd,
         stdin=subprocess42.PIPE,
         stdout=subprocess42.PIPE, stderr=subprocess42.STDOUT,
         cwd=botobj.base_dir,
@@ skipping 316 matching lines @@
       auth_params_dumper.start()
 
     command = [
       sys.executable, THIS_FILE, 'task_runner',
       '--swarming-server', url,
       '--in-file', task_in_file,
       '--out-file', task_result_file,
       '--cost-usd-hour', str(botobj.state.get('cost_usd_hour') or 0.),
       # Include the time taken to poll the task in the cost.
       '--start', str(start),
-      '--min-free-space', str(get_min_free_space(botobj)),
+      '--min-free-space', str(get_desired_free_space(botobj)),
       '--bot-file', bot_file,
     ]
     if botobj.remote.uses_auth:
       command.extend(['--auth-params-file', auth_params_file])
     if is_grpc:
       command.append('--is-grpc')
     logging.debug('Running command: %s', command)
 
     # Put the output file into the current working directory, which should be
     # the one containing swarming_bot.zip.
@@ skipping 201 matching lines @@
 
   error = None
   if len(args) != 0:
     error = 'Unexpected arguments: %s' % args
   try:
     return run_bot(error)
   finally:
     call_hook(
         bot.Bot(None, None, None, None, base_dir, None), 'on_bot_shutdown')
     logging.info('main() returning')