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add schema upgrades

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This commit is contained in:
Brian Warner 2016-06-20 17:29:34 -07:00
parent 38ebc0d8a4
commit 7250deb94c
1 changed files with 22 additions and 6 deletions
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28
src/wormhole/server/database.py
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@ -11,6 +11,12 @@ def get_schema(version):
"db-schemas/v%d.sql" % version) "db-schemas/v%d.sql" % version)
return schema_bytes.decode("utf-8") return schema_bytes.decode("utf-8")
def get_upgrader(new_version):
schema_bytes = resource_string("wormhole.server",
"db-schemas/upgrade-to-v%d.sql" % new_version)
return schema_bytes.decode("utf-8")
TARGET_VERSION = 2
def dict_factory(cursor, row): def dict_factory(cursor, row):
d = {} d = {}
@ -18,23 +24,23 @@ def dict_factory(cursor, row):
d[col[0]] = row[idx] d[col[0]] = row[idx]
return d return d
def get_db(dbfile, stderr=sys.stderr): def get_db(dbfile, target_version=TARGET_VERSION, stderr=sys.stderr):
"""Open or create the given db file. The parent directory must exist. """Open or create the given db file. The parent directory must exist.
Returns the db connection object, or raises DBError. Returns the db connection object, or raises DBError.
""" """
must_create = not os.path.exists(dbfile) must_create = (dbfile == ":memory:") or not os.path.exists(dbfile)
try: try:
db = sqlite3.connect(dbfile) db = sqlite3.connect(dbfile)
except (EnvironmentError, sqlite3.OperationalError) as e: except (EnvironmentError, sqlite3.OperationalError) as e:
raise DBError("Unable to create/open db file %s: %s" % (dbfile, e)) raise DBError("Unable to create/open db file %s: %s" % (dbfile, e))
db.row_factory = dict_factory db.row_factory = dict_factory
VERSION = 2
if must_create: if must_create:
schema = get_schema(VERSION) schema = get_schema(target_version)
db.executescript(schema) db.executescript(schema)
db.execute("INSERT INTO version (version) VALUES (?)", (VERSION,)) db.execute("INSERT INTO version (version) VALUES (?)",
(target_version,))
db.commit() db.commit()
try: try:
@ -44,7 +50,17 @@ def get_db(dbfile, stderr=sys.stderr):
# Perhaps it was created with an old version, or it might be junk. # Perhaps it was created with an old version, or it might be junk.
raise DBError("db file is unusable: %s" % e) raise DBError("db file is unusable: %s" % e)
if version != VERSION: while version < target_version:
try:
upgrader = get_upgrader(version+1)
except ValueError: # ResourceError??
raise DBError("Unable to upgrade %s to version %s, left at %s"
% (dbfile, version+1, version))
db.executescript(upgrader)
db.commit()
version = version+1
if version != target_version:
raise DBError("Unable to handle db version %s" % version) raise DBError("Unable to handle db version %s" % version)
return db return db