watcher-db-manage¶
The watcher-db-manage utility is used to create the database schema tables that the watcher services will use for storage. It can also be used to upgrade (or downgrade) existing database tables when migrating between different versions of watcher.
The Alembic library is used to perform the database migrations.
Options¶
This is a partial list of the most useful options. To see the full list, run the following:
watcher-db-manage --help
- -h, --help¶
Show help message and exit.
- --config-dir <DIR>¶
Path to a config directory with configuration files.
- --config-file <PATH>¶
Path to a configuration file to use.
- -d, --debug¶
Print debugging output.
- -v, --verbose¶
Print more verbose output.
- --version¶
Show the program’s version number and exit.
Usage¶
Options for the various commands for
watcher-db-manage are listed when the -h or
--help
option is used after the command.
For example:
watcher-db-manage create_schema --help
Information about the database is read from the watcher configuration file
used by the API server and conductor services. This file must be specified
with the --config-file option:
watcher-db-manage --config-file /path/to/watcher.conf create_schema
The configuration file defines the database backend to use with the connection database option:
[database]
connection=mysql://root@localhost/watcher
If no configuration file is specified with the --config-file option,
watcher-db-manage assumes an SQLite database.
Command Options¶
watcher-db-manage is given a command that tells the utility what actions to perform. These commands can take arguments. Several commands are available:
create_schema¶
- -h, --help¶
Show help for create_schema and exit.
This command will create database tables based on the most current version. It assumes that there are no existing tables.
An example of creating database tables with the most recent version:
watcher-db-manage --config-file=/etc/watcher/watcher.conf create_schema
downgrade¶
- -h, --help¶
Show help for downgrade and exit.
- --revision <REVISION>¶
The revision number you want to downgrade to.
This command will revert existing database tables to a previous version.
The version can be specified with the --revision option.
An example of downgrading to table versions at revision 2581ebaf0cb2:
watcher-db-manage --config-file=/etc/watcher/watcher.conf downgrade --revision 2581ebaf0cb2
revision¶
- -h, --help¶
Show help for revision and exit.
- -m <MESSAGE>, --message <MESSAGE>¶
The message to use with the revision file.
- --autogenerate¶
Compares table metadata in the application with the status of the database and generates migrations based on this comparison.
This command will create a new revision file. You can use the
--message option to comment the revision.
This is really only useful for watcher developers making changes that require database changes. This revision file is used during database migration and will specify the changes that need to be made to the database tables. Further discussion is beyond the scope of this document.
stamp¶
- -h, --help¶
Show help for stamp and exit.
- --revision <REVISION>¶
The revision number.
This command will ‘stamp’ the revision table with the version specified with
the --revision option. It will not run any migrations.
upgrade¶
- -h, --help¶
Show help for upgrade and exit.
- --revision <REVISION>¶
The revision number to upgrade to.
This command will upgrade existing database tables to the most recent version,
or to the version specified with the --revision option.
If there are no existing tables, then new tables are created, beginning with the oldest known version, and successively upgraded using all of the database migration files, until they are at the specified version. Note that this behavior is different from the create_schema command that creates the tables based on the most recent version.
An example of upgrading to the most recent table versions:
watcher-db-manage --config-file=/etc/watcher/watcher.conf upgrade
Note
This command is the default if no command is given to watcher-db-manage.
Warning
The upgrade command is not compatible with SQLite databases since it uses ALTER TABLE commands to upgrade the database tables. SQLite supports only a limited subset of ALTER TABLE.
version¶
- -h, --help¶
Show help for version and exit.
This command will output the current database version.
purge¶
- -h, --help¶
Show help for purge and exit.
- -d, --age-in-days¶
The number of days (starting from today) before which we consider soft deleted objects as expired and should hence be erased. By default, all objects soft deleted are considered expired. This can be useful as removing a significant amount of objects may cause a performance issues.
- -n, --max-number¶
The maximum number of database objects we expect to be deleted. If exceeded, this will prevent any deletion.
- -t, --goal¶
Either the UUID or name of the goal to purge.
- -e, --exclude-orphans¶
This is a flag to indicate when we want to exclude orphan objects from deletion.
- --dry-run¶
This is a flag to indicate when we want to perform a dry run. This will show the objects that would be deleted instead of actually deleting them.
This command will purge the current database by removing both its soft deleted and orphan objects.
