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from cli import CLI
from log import LOG
from core import Migration, SimpleDBMigrate
from helpers import Lists
from config import Config
"""
The sgbd class should implement the following methods
- change(self, sql, new_db_version, migration_file_name, sql_up, sql_down, up=True, execution_log=None, label_version=None)
executes the migration (up or down) and records the change on version table
- get_all_schema_migrations(self)
return all migrations saved on version table
- get_all_schema_versions(self)
return all versions saved on version table
- get_current_schema_version(self)
return the current schema version
- get_version_id_from_version_number(self, version)
return the id from an specific version
- get_version_number_from_label(self, label)
return the version of the last migration executed under the label
"""
class Main(object):
def __init__(self, config, sgdb=None):
Main._check_configuration(config)
self.cli = CLI()
self.config = config
self.log = LOG(self.config.get("log_dir", None))
self.sgdb = sgdb
if self.sgdb is None and not self.config.get("new_migration", None):
if self.config.get("database_engine") == 'mysql':
from mysql import MySQL
self.sgdb = MySQL(config)
elif self.config.get("database_engine") == 'oracle':
from oracle import Oracle
self.sgdb = Oracle(config)
elif self.config.get("database_engine") == 'mssql':
from mssql import MSSQL
self.sgdb = MSSQL(config)
else:
raise Exception("engine not supported '%s'" % self.config.get("database_engine"))
self.db_migrate = SimpleDBMigrate(self.config)
def execute(self):
self._execution_log("\nStarting DB migration...", "PINK", log_level_limit=1)
if self.config.get("new_migration", None):
self._create_migration()
else:
self._migrate()
self._execution_log("\nDone.\n", "PINK", log_level_limit=1)
@staticmethod
def _check_configuration(config):
if not isinstance(config, Config):
raise Exception("config must be an instance of simple_db_migrate.config.Config")
required_configs = ['database_host', 'database_name', 'database_user', 'database_password', 'database_migrations_dir', 'database_engine', 'schema_version']
if config.get("new_migration", None):
required_configs = ['database_migrations_dir']
for key in required_configs:
#check if config has the key, if do not have will raise exception
config.get(key)
def _create_migration(self):
migrations_dir = self.config.get("database_migrations_dir")
new_file = Migration.create(self.config.get("new_migration", None), migrations_dir[0], self.config.get("database_script_encoding", "utf-8"), self.config.get("utc_timestamp", False))
self._execution_log("- Created file '%s'" % (new_file), log_level_limit=1)
def _migrate(self):
destination_version = self._get_destination_version()
current_version = self.sgdb.get_current_schema_version()
# do it!
self._execute_migrations(current_version, destination_version)
def _get_destination_version(self):
label_version = self.config.get("label_version", None)
schema_version = self.config.get("schema_version", None)
destination_version = None
destination_version_by_label = None
destination_version_by_schema = None
if label_version is not None:
destination_version_by_label = self.sgdb.get_version_number_from_label(label_version)
"""
if specified label exists at database and schema version was not specified,
is equivalent to run simple-db-migrate with schema_version equals to the version with specified label
"""
if destination_version_by_label is not None and schema_version is None:
schema_version = destination_version_by_label
self.config.update("schema_version", destination_version_by_label)
if schema_version is not None and self.sgdb.get_version_id_from_version_number(schema_version):
destination_version_by_schema = schema_version
if label_version is None:
if schema_version is None:
destination_version = self.db_migrate.latest_version_available()
elif destination_version_by_schema is None:
destination_version = schema_version
else:
destination_version = destination_version_by_schema
else:
if schema_version is None:
destination_version = self.db_migrate.latest_version_available()
elif (destination_version_by_label is None) or (destination_version_by_schema == destination_version_by_label):
destination_version = schema_version
if (destination_version_by_schema is not None) and (destination_version_by_label is not None) and (destination_version_by_schema != destination_version_by_label):
raise Exception("label (%s) and schema_version (%s) don't correspond to the same version at database" % (label_version, schema_version))
if (schema_version is not None and label_version is not None) and ((destination_version_by_schema is not None and destination_version_by_label is None) or (destination_version_by_schema is None and destination_version_by_label is not None)):
raise Exception("label (%s) or schema_version (%s), only one of them exists in the database" % (label_version, schema_version))
if destination_version is not '0' and not (self.db_migrate.check_if_version_exists(destination_version) or self.sgdb.get_version_id_from_version_number(destination_version)):
raise Exception("version not found (%s)" % destination_version)
return destination_version
def _get_migration_files_to_be_executed(self, current_version, destination_version, is_migration_up):
if current_version == destination_version and not self.config.get("force_execute_old_migrations_versions", False):
return []
schema_migrations = self.sgdb.get_all_schema_migrations()
available_migrations = self.db_migrate.get_all_migrations()
# migration up
if is_migration_up:
remaining_migrations = Lists.subtract(available_migrations, schema_migrations)
remaining_migrations_to_execute = [migration for migration in remaining_migrations if migration.version <= destination_version]
return remaining_migrations_to_execute
# migration down...
destination_version_id = self.sgdb.get_version_id_from_version_number(destination_version)
migration_versions = self.db_migrate.get_all_migration_versions()
down_migrations_to_execute = [migration for migration in schema_migrations if migration.id > destination_version_id]
force_files = self.config.get("force_use_files_on_down", False)
for migration in down_migrations_to_execute:
if not migration.sql_down or force_files:
if migration.version not in migration_versions:
raise Exception("impossible to migrate down: one of the versions was not found (%s)" % migration.version)
migration_tmp = self.db_migrate.get_migration_from_version_number(migration.version)
migration.sql_up = migration_tmp.sql_up
migration.sql_down = migration_tmp.sql_down
migration.file_name = migration_tmp.file_name
down_migrations_to_execute.reverse()
return down_migrations_to_execute
def _execute_migrations(self, current_version, destination_version):
"""
passed a version:
this version don't exists in the database and is younger than the last version -> do migrations up until this version
this version don't exists in the database and is older than the last version -> do nothing, is a unpredictable behavior
this version exists in the database and is older than the last version -> do migrations down until this version
didn't pass a version -> do migrations up until the last available version
"""
is_migration_up = True
# check if a version was passed to the program
if self.config.get("schema_version"):
# if was passed and this version is present in the database, check if is older than the current version
destination_version_id = self.sgdb.get_version_id_from_version_number(destination_version)
if destination_version_id:
current_version_id = self.sgdb.get_version_id_from_version_number(current_version)
# if this version is previous to the current version in database, then will be done a migration down to this version
if current_version_id > destination_version_id:
is_migration_up = False
# if was passed and this version is not present in the database and is older than the current version, raise an exception
# cause is trying to go down to something that never was done
elif current_version > destination_version:
raise Exception("Trying to migrate to a lower version wich is not found on database (%s)" % destination_version)
# getting only the migration sql files to be executed
migrations_to_be_executed = self._get_migration_files_to_be_executed(current_version, destination_version, is_migration_up)
self._execution_log("- Current version is: %s" % current_version, "GREEN", log_level_limit=1)
if migrations_to_be_executed is None or len(migrations_to_be_executed) == 0:
self._execution_log("- Destination version is: %s" % current_version, "GREEN", log_level_limit=1)
self._execution_log("\nNothing to do.\n", "PINK", log_level_limit=1)
return
self._execution_log("- Destination version is: %s" % (is_migration_up and migrations_to_be_executed[-1].version or destination_version), "GREEN", log_level_limit=1)
up_down_label = is_migration_up and "up" or "down"
if self.config.get("show_sql_only", False):
self._execution_log("\nWARNING: database migrations are not being executed ('--showsqlonly' activated)", "YELLOW", log_level_limit=1)
else:
self._execution_log("\nStarting migration %s!" % up_down_label, log_level_limit=1)
self._execution_log("*** versions: %s\n" % ([ migration.version for migration in migrations_to_be_executed]), "CYAN", log_level_limit=1)
sql_statements_executed = []
for migration in migrations_to_be_executed:
sql = is_migration_up and migration.sql_up or migration.sql_down
if not self.config.get("show_sql_only", False):
self._execution_log("===== executing %s (%s) =====" % (migration.file_name, up_down_label), log_level_limit=1)
label = None
if is_migration_up:
label = self.config.get("label_version", None)
try:
self.sgdb.change(sql, migration.version, migration.file_name, migration.sql_up, migration.sql_down, is_migration_up, self._execution_log, label)
except Exception, e:
self._execution_log("===== ERROR executing %s (%s) =====" % (migration.abspath, up_down_label), log_level_limit=1)
raise e
# paused mode
if self.config.get("paused_mode", False):
raw_input("* press <enter> to continue... ")
# recording the last statement executed
sql_statements_executed.append(sql)
if self.config.get("show_sql", False) or self.config.get("show_sql_only", False):
self._execution_log("__________ SQL statements executed __________", "YELLOW", log_level_limit=1)
for sql in sql_statements_executed:
self._execution_log(sql, "YELLOW", log_level_limit=1)
self._execution_log("_____________________________________________", "YELLOW", log_level_limit=1)
def _execution_log(self, msg, color="CYAN", log_level_limit=2):
if self.config.get("log_level", 1) >= log_level_limit:
CLI.msg(msg, color)
self.log.debug(msg)
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