Source Code for Module buildbot.db.schema.manager

 1  # This file is part of Buildbot.  Buildbot is free software: you can 
 2  # redistribute it and/or modify it under the terms of the GNU General Public 
 3  # License as published by the Free Software Foundation, version 2. 
 4  # 
 5  # This program is distributed in the hope that it will be useful, but WITHOUT 
 6  # ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS 
 7  # FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more 
 8  # details. 
 9  # 
10  # You should have received a copy of the GNU General Public License along with 
11  # this program; if not, write to the Free Software Foundation, Inc., 51 
12  # Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. 
13  # 
14  # Copyright Buildbot Team Members 
15   
16  from twisted.python import reflect 
17   
18  # note that schema modules are not loaded unless an upgrade is taking place 
19   
20  CURRENT_VERSION = 6 
21   
22 -class DBSchemaManager(object): 
23      """ 
24      This class is responsible for managing the database schema and upgrading it 
25      as necessary.  This includes both the *actual* database and the old pickle 
26      database, as migrations move data between the two. 
27   
28      Note that this class is *entirely synchronous*!  Performing any other operations 
29      while changing the schema is just asking for trouble. 
30      """ 
31 -    def __init__(self, spec, basedir): 
32          self.spec = spec 
33          self.basedir = basedir 
34          self.dbapi = self.spec.get_dbapi() 
35   
36 -    def get_db_version(self, conn=None): 
37          """ 
38          Get the current schema version for this database 
39          """ 
40          close_conn = False 
41          if not conn: 
42              conn = self.spec.get_sync_connection() 
43              close_conn = True 
44          c = conn.cursor() 
45          try: 
46              try: 
47                  c.execute("SELECT version FROM version") 
48                  rows = c.fetchall() 
49                  assert len(rows) == 1, "%i rows in version table! (should only be 1)" % len(rows) 
50                  return rows[0][0] 
51              except (self.dbapi.OperationalError, self.dbapi.ProgrammingError): 
52                  # no version table = version 0 
53                  return 0 
54          finally: 
55              if close_conn: 
56                  conn.close() 
57   
58 -    def get_current_version(self): 
59          """ 
60          Get the current db version for this release of buildbot 
61          """ 
62          return CURRENT_VERSION 
63   
64 -    def is_current(self): 
65          """ 
66          Is this database current? 
67          """ 
68          return self.get_db_version() == self.get_current_version() 
69   
70 -    def upgrade(self, quiet=False): 
71          """ 
72          Upgrade this database to the current version 
73          """ 
74          conn = self.spec.get_sync_connection() 
75          try: 
76              while self.get_db_version() < self.get_current_version(): 
77                  next_version = self.get_db_version() + 1 
78                  next_version_module = reflect.namedModule("buildbot.db.schema.v%d" % next_version) 
79                  upg = next_version_module.Upgrader(self.dbapi, conn, self.basedir, quiet) 
80                  upg.upgrade() 
81                  conn.commit() 
82                  assert self.get_db_version() == next_version 
83          finally: 
84              conn.close() 
85