1 from __future__ import print_function
6 from sqlalchemy import MetaData, Table
7 from sqlalchemy.exc import NoSuchTableError
9 import migrate.versioning.api as migrate
11 from sfa.util.sfalogging import logger
12 import sfa.storage.model as model
14 # this class takes care of database upgrades
15 # upgrade from a pre-2.1 db
16 # * 1.0 and up to 1.1-4: ('very old')
17 # was piggybacking the planetlab5 database
18 # this is kind of out of our scope here, we don't have the credentials
19 # to connect to planetlab5, but this is documented in
20 # https://svn.planet-lab.org/wiki/SFATutorialConfigureSFA#Upgradingnotes
21 # and essentially this is seamless to users
22 # * from 1.1-5 up to 2.0-x: ('old')
23 # uses the 'sfa' db and essentially the 'records' table,
24 # as well as record_types
25 # together with an 'sfa_db_version' table (version, subversion)
27 # we have an 'records' table, plus 'users' and the like
28 # and once migrate has kicked in there is a table named (see migrate.cfg)
29 # migrate_db_version (repository_id, repository_path, version)
31 # Starting with 2.1, we use sqlalchemy-migrate scripts in a standard way
32 # Note that the model defined in sfa.storage.model needs to be maintained
33 # as the 'current/latest' version, and newly installed deployments will
34 # then 'jump' to the latest version number without going through the migrations
36 # An initial attempt to run this as a 001_*.py migrate script
37 # did not quite work out (essentially we need to set the current version
38 # number out of the migrations logic)
39 # also this approach has less stuff in the initscript, which seems just right
44 header = "Upgrading to 2.1 or higher"
47 from sfa.storage.alchemy import alchemy
48 self.url = alchemy.url
49 self.engine = alchemy.engine
50 self.repository = "/usr/share/sfa/migrations"
52 def current_version(self):
54 return migrate.db_version(self.url, self.repository)
58 def table_exists(self, tablename):
60 metadata = MetaData(bind=self.engine)
61 table = Table(tablename, metadata, autoload=True)
63 except NoSuchTableError:
66 def drop_table(self, tablename):
67 if self.table_exists(tablename):
68 print("%s: Dropping table %s" %
69 (DBSchema.header, tablename), file=sys.stderr)
70 self.engine.execute("drop table %s cascade" % tablename)
72 print("%s: no need to drop table %s" %
73 (DBSchema.header, tablename), file=sys.stderr)
75 def handle_old_releases(self):
77 # try to find out which old version this can be
78 if not self.table_exists('records'):
80 # (.) we've just created the db, so it's either a fresh install, or
81 # (.) we come from a 'very old' depl.
82 # in either case, an import is required but there's nothing to
84 print("%s: make sure to run import" %
85 (DBSchema.header,), file=sys.stderr)
86 elif self.table_exists('sfa_db_version'):
87 # we come from an 'old' version
88 self.drop_table('records')
89 self.drop_table('record_types')
90 self.drop_table('sfa_db_version')
92 # we should be good here
95 print("%s: unknown exception" %
96 (DBSchema.header,), file=sys.stderr)
99 # after this call the db schema and the version as known by migrate should
100 # reflect the current data model and the latest known version
101 def init_or_upgrade(self):
102 # check if under version control, and initialize it otherwise
103 if self.current_version() is None:
105 # can be either a very old version, or a fresh install
106 # for very old versions:
107 self.handle_old_releases()
108 # in any case, initialize db from current code and reflect in
110 model.init_tables(self.engine)
111 code_version = migrate.version(self.repository)
112 migrate.version_control(self.url, self.repository, code_version)
113 after = "%s" % self.current_version()
114 logger.info("DBSchema : jumped to version %s" % (after))
116 # use migrate in the usual way
117 before = "%s" % self.current_version()
118 migrate.upgrade(self.url, self.repository)
119 after = "%s" % self.current_version()
121 logger.info("DBSchema : upgraded version from %s to %s" %
125 "DBSchema : no change needed in db schema (%s==%s)" % (before, after))
127 # this trashes the db altogether, from the current model in sfa.storage.model
128 # I hope this won't collide with ongoing migrations and all
129 # actually, now that sfa uses its own db, this is essentially equivalent to
130 # dropping the db entirely, modulo a 'service sfa start'
132 model.drop_tables(self.engine)
133 # so in this case it's like we haven't initialized the db at all
135 migrate.drop_version_control(self.url, self.repository)
136 except migrate.exceptions.DatabaseNotControlledError:
137 logger.log_exc("Failed to drop version control")
140 if __name__ == '__main__':
141 DBSchema().init_or_upgrade()