4 # Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011, 2012 Google Inc.
6 # This program is free software; you can redistribute it and/or modify
7 # it under the terms of the GNU General Public License as published by
8 # the Free Software Foundation; either version 2 of the License, or
9 # (at your option) any later version.
11 # This program is distributed in the hope that it will be useful, but
12 # WITHOUT ANY WARRANTY; without even the implied warranty of
13 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 # General Public License for more details.
16 # You should have received a copy of the GNU General Public License
17 # along with this program; if not, write to the Free Software
18 # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
22 """Module implementing the job queue handling."""
27 from ganeti import constants
28 from ganeti import errors
29 from ganeti import runtime
30 from ganeti import utils
31 from ganeti import pathutils
34 JOBS_PER_ARCHIVE_DIRECTORY = 10000
37 def _ReadNumericFile(file_name):
38 """Reads a file containing a number.
41 @return: None if file is not found, otherwise number
45 return int(utils.ReadFile(file_name))
46 except EnvironmentError, err:
47 if err.errno in (errno.ENOENT, ):
53 """Read the serial file.
55 The queue should be locked while this function is called.
58 return _ReadNumericFile(pathutils.JOB_QUEUE_SERIAL_FILE)
62 """Read the queue version.
64 The queue should be locked while this function is called.
67 return _ReadNumericFile(pathutils.JOB_QUEUE_VERSION_FILE)
70 def InitAndVerifyQueue(must_lock):
71 """Open and lock job queue.
73 If necessary, the queue is automatically initialized.
76 @param must_lock: Whether an exclusive lock must be held.
77 @rtype: utils.FileLock
78 @return: Lock object for the queue. This can be used to change the
82 getents = runtime.GetEnts()
85 queue_lock = utils.FileLock.Open(pathutils.JOB_QUEUE_LOCK_FILE)
87 # The queue needs to be locked in exclusive mode to write to the serial and
90 queue_lock.Exclusive(blocking=True)
94 queue_lock.Exclusive(blocking=False)
96 except errors.LockError:
97 # Ignore errors and assume the process keeping the lock checked
103 version = ReadVersion()
105 # Write new version file
106 utils.WriteFile(pathutils.JOB_QUEUE_VERSION_FILE,
107 uid=getents.masterd_uid, gid=getents.masterd_gid,
108 data="%s\n" % constants.JOB_QUEUE_VERSION)
111 version = ReadVersion()
113 if version != constants.JOB_QUEUE_VERSION:
114 raise errors.JobQueueError("Found job queue version %s, expected %s",
115 version, constants.JOB_QUEUE_VERSION)
117 serial = ReadSerial()
119 # Write new serial file
120 utils.WriteFile(pathutils.JOB_QUEUE_SERIAL_FILE,
121 uid=getents.masterd_uid, gid=getents.masterd_gid,
125 serial = ReadSerial()
128 # There must be a serious problem
129 raise errors.JobQueueError("Can't read/parse the job queue"
133 # There's no need for more error handling. Closing the lock
134 # file below in case of an error will unlock it anyway.
144 def CheckDrainFlag():
145 """Check if the queue is marked to be drained.
147 This currently uses the queue drain file, which makes it a per-node flag.
148 In the future this can be moved to the config file.
151 @return: True if the job queue is marked drained
154 return os.path.exists(pathutils.JOB_QUEUE_DRAIN_FILE)
157 def SetDrainFlag(drain_flag):
158 """Sets the drain flag for the queue.
160 @type drain_flag: boolean
161 @param drain_flag: Whether to set or unset the drain flag
162 @attention: This function should only called the current holder of the queue
166 getents = runtime.GetEnts()
169 utils.WriteFile(pathutils.JOB_QUEUE_DRAIN_FILE, data="",
170 uid=getents.masterd_uid, gid=getents.masterd_gid)
172 utils.RemoveFile(pathutils.JOB_QUEUE_DRAIN_FILE)
174 assert (not drain_flag) ^ CheckDrainFlag()
177 def FormatJobID(job_id):
178 """Convert a job ID to int format.
180 Currently this just is a no-op that performs some checks, but if we
181 want to change the job id format this will abstract this change.
183 @type job_id: int or long
184 @param job_id: the numeric job id
186 @return: the formatted job id
189 if not isinstance(job_id, (int, long)):
190 raise errors.ProgrammerError("Job ID '%s' not numeric" % job_id)
192 raise errors.ProgrammerError("Job ID %s is negative" % job_id)
197 def GetArchiveDirectory(job_id):
198 """Returns the archive directory for a job.
201 @param job_id: Job identifier
203 @return: Directory name
206 return str(ParseJobId(job_id) / JOBS_PER_ARCHIVE_DIRECTORY)
209 def ParseJobId(job_id):
210 """Parses a job ID and converts it to integer.
215 except (ValueError, TypeError):
216 raise errors.ParameterError("Invalid job ID '%s'" % job_id)