Add master_cleaner tool.

infra/tools/master_cleaner/__main__.py

Index: infra/tools/master_cleaner/__main__.py
diff --git a/infra/tools/master_cleaner/__main__.py b/infra/tools/master_cleaner/__main__.py
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+#!/usr/bin/python
+# Copyright 2015 Google Inc. All Rights Reserved.

[nodir, 2016/06/10 17:50:36]

2016

+# pylint: disable=F0401
+
+"""Cleanup directories on BuildBot master systems."""
+
+import argparse
+import bisect
+import datetime
+import json
+import logging
+import os
+import shutil
+import subprocess
+import sys
+import time
+
+from infra_libs import logs
+from infra_libs.time_functions.parser import timedelta_type
+
+
+LOGGER = logging.getLogger(__name__)
+
+
+def _check_run(cmd, dry_run=True, cwd=None):
+  if cwd is None:
+    cwd = os.getcwd()
+
+  if dry_run:
+    LOGGER.info('(Dry run) Running command %s (cwd=%s)', cmd, cwd)
+    return '', ''
+
+  LOGGER.debug('Running command %s (cwd=%s)', cmd, cwd)
+  proc = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE,
+                          cwd=cwd)
+  stdout, stderr = proc.communicate()
+
+  rc = proc.returncode
+  if rc != 0:
+    LOGGER.error('Output for process %s (cwd=%s):\nSTDOUT:\n%s\nSTDERR:\n%s',
+                 cmd, cwd, stdout, stderr)

[nodir, 2016/06/10 17:50:36]

include exit code

[dnj (Google), 2016/06/10 18:00:52]

Done.

+    raise subprocess.CalledProcessError(rc, cmd, None)
+  return stdout, stderr
+
+
+def parse_args(argv):
+  parser = argparse.ArgumentParser(
+      description='Cleanup directories on BuildBot master systems.')

[nodir, 2016/06/10 17:50:36]

__doc__

[dnj (Google), 2016/06/10 18:00:52]

Done.

+  parser.add_argument('master', nargs='+',
+      help='Name of masters (*, master.*) to clean.')
+  parser.add_argument('--max-twistd-log-age', default=None, type=timedelta_type,
+      help='If set, "twistd.log" files older than this will be purged.')
+  parser.add_argument('--production', action='store_true',
+      help='If set, actually delete the files instead of listing them.')
+  parser.add_argument('--gclient-root',
+      help='The path to the directory containing the master checkout '
+           '".gclient" file. If omitted, an attempt will be made to probe '
+           'one.')
+
+  logs.add_argparse_options(parser)
+
+  opts = parser.parse_args(argv)
+  logs.process_argparse_options(opts)
+  return opts
+
+
+def _process_master(opts, master_cfg):
+  LOGGER.info('Cleaning up master: %s', master_cfg['mastername'])
+
+  # Get a list of all files within the master directory.
+  master_dir = master_cfg['master_dir']
+  files, dirs = _list_untracked_files(master_dir)
+
+  # Filter out all directories that are current builddirs or aren't builder
+  # directories.

[nodir, 2016/06/10 17:50:36]

two negations (filter and aren't), hard to understand

[dnj (Google), 2016/06/10 18:00:52]

Done.

+  dirs = [x for x in dirs if (
+      x not in master_cfg['builddirs'] and
+      _is_builder_dir(os.path.join(master_dir, x)))]
+  LOGGER.info('Identified %d superfluous build directories.', len(dirs))
+
+  # Find old "twistd.log" files.
+  old_twistd_logs = _find_old_twistd_logs(master_dir, files,
+                                          opts.max_twistd_log_age)
+  if len(old_twistd_logs) > 0:
+    LOGGER.info('Identified %d old twistd.log files, starting with %s.',
+                len(old_twistd_logs), old_twistd_logs[-1])
+
+  for d in dirs:
+    d = os.path.join(master_dir, d)
+    LOGGER.info('Deleting superfluous directory: [%s]', d)
+    if not opts.production:
+      LOGGER.info('(Dry Run) Not deleting.')
+      continue
+    shutil.rmtree(d)
+
+  for f in old_twistd_logs:
+    f = os.path.join(master_dir, f)
+    LOGGER.info('Removing old "twistd.log" file: [%s]', f)
+    if not opts.production:
+      LOGGER.info('(Dry Run) Not deleting.')
+      continue
+    os.remove(f)
+
+
+def _find_old_twistd_logs(base, files, max_age):
+  twistd_log_files = []
+  if max_age is None:
+    return twistd_log_files
+
+  # Identify all "twistd.log" files to delete. We will do this by binary
+  # searching the "twistd.log" space under the assumption that any log files
+  # with higher suffix than the specified file are older than it.
+  for f in files:
+    gen = _parse_twistd_log_generation(f)
+    if gen is not None:
+      twistd_log_files.append((f, gen))
+  twistd_log_files.sort(key=lambda x: x[1])
+
+  threshold = datetime.datetime.now() - max_age
+  lo, hi = 0, len(twistd_log_files)
+  while lo < hi:
+    mid = (lo+hi)//2
+    path = os.path.join(base, twistd_log_files[mid][0])
+    age = datetime.datetime.fromtimestamp(os.path.getctime(path))

[nodir, 2016/06/10 17:50:36]

it is not age (the older the file, the bigger the age), but rather birth date
(the older the file, the lower the birth date): direction is reversed

[nodir, 2016/06/10 17:50:36]

I think this should use twistd_log_files[mid][1]
otherwise you sort by second value in tuple, but binary-search by something else
also less io

[dnj (Google), 2016/06/10 18:00:52]

I think it's correct now.

+    if age < threshold:
+      hi = mid
+    else:
+      lo = mid+1
+  return [x[0] for x in twistd_log_files[:lo]]
+
+
+def _parse_twistd_log_generation(v):
+  # Format is: "twistd.log[.###]"
+  pieces = v.split('.')
+  if len(pieces) != 3 or not (pieces[0] == 'twistd' and pieces[1] == 'log'):
+    return None
+
+  try:
+    return int(pieces[2])
+  except ValueError:
+    return None
+
+
+def _list_untracked_files(path):
+  cmd = ['git', '-C', path, 'ls-files', '.', '--others', '--directory', '-z']
+  stdout, _ = _check_run(cmd, dry_run=False)
+  files, dirs = [], []
+
+  def iter_null_terminated(data):
+    while True:
+      idx = data.find('\0')
+      if idx < 0:
+        yield data
+        return
+      v, data = data[:idx], data[idx+1:]
+      yield v
+
+  for name in iter_null_terminated(stdout):
+    if name.endswith('/'):
+      dirs.append(name.rstrip('/'))
+    else:
+      files.append(name)
+  return files, dirs
+
+
+def _is_builder_dir(dirname):
+  return os.path.isfile(os.path.join(dirname, 'builder'))
+
+
+def _load_master_cfg(gclient_root, master_dir):
+  dump_master_cfg = os.path.join(gclient_root, 'build', 'scripts', 'tools',
+                                 'dump_master_cfg.py')
+
+  cmd = [sys.executable, dump_master_cfg, master_dir, '-']
+  config, _ = _check_run(cmd, dry_run=False)
+  config = json.loads(config)
+
+  result = {
+    'mastername': os.path.split(master_dir)[1],

[nodir, 2016/06/10 17:50:36]

this should be -1

[dnj (Google), 2016/06/10 18:00:52]

Done.

+    'master_dir': master_dir,
+    'builddirs': set(),
+  }
+  for bcfg in config.get('builders', ()):
+    result['builddirs'].add(bcfg['builddir'])

[nodir, 2016/06/10 17:50:36]

builddir is not always there, e.g. 
  ./scripts/tools/dump_master_cfg.py masters/master.tryserver.infra/ -
does not contain builddirs
i think it should be bcfg.get('builddir', bcfg['name'])

otherwise you may nuke a lot of build dirs

[dnj (Google), 2016/06/10 18:00:52]

Done.

+  return result
+
+
+def _find_master(gclient_root, mastername):
+  if not mastername.startswith('master.'):
+    mastername = 'master.' + mastername
+
+  for candidate in (
+      os.path.join(gclient_root, 'build', 'masters'),
+      os.path.join(gclient_root, 'build_internal', 'masters'),
+  ):
+    candidate = os.path.join(candidate, mastername)
+    if os.path.isdir(candidate):
+      return candidate
+  raise ValueError('Unable to locate master %s' % (mastername,))
+
+
+def _find_gclient_root(opts):
+  for candidate in (
+      opts.gclient_root,
+      os.path.join(os.path.expanduser('~'), 'buildbot'),
+  ):
+    if not candidate:
+      continue
+    candidate = os.path.abspath(candidate)
+    if os.path.isfile(os.path.join(candidate, '.gclient')):
+      return candidate
+  raise Exception('Unable to find ".gclient" root.')
+
+
+def _trim_prefix(v, prefix):
+  if v.startswith(prefix):
+    v = v[len(prefix)]
+  return v
+
+
+def _main(argv):
+  opts = parse_args(argv)
+
+  # Locate our gclient file root.
+  gclient_root = _find_gclient_root(opts)
+
+  # Dump the builders configured for each master.
+  for master in sorted(set(opts.master)):

[nodir, 2016/06/10 17:50:36]

why set? you sort it anyway

[dnj (Google), 2016/06/10 18:00:52]

Just in case some person specifies the same master twice.

+    LOGGER.info('Loading configuration for master "%s"...', master)
+    master_dir = _find_master(gclient_root, master)
+    master_cfg = _load_master_cfg(gclient_root, master_dir)
+    _process_master(opts, master_cfg)
+
+  return 0
+
+if __name__ == '__main__':
+  sys.exit(_main(sys.argv[1:]))