Checks Python API Helper Scripts

Liquibase provides an API that contains helper scripts to enable users to write Python custom policy checks. You can implement any of the helper scripts listed below into your custom policy check to narrow down the content you are searching for. Learn more about how to use these functions by reading our Custom Policy Checks documentation.

Changeset attributes

These attributes are functions available to you after importing the liquibase_changesets file that allow you to pull this content from the given changeset path. The changeset is always the input parameter for these attributes.

Function	Return
`get_author`(changeset)	Provides the changeset author
`get_contexts`(changeset)	Provides the changeset contexts
`get_file_path`(changeset)	Provides the changeset file path
`get_id`(changeset)	Provides the changeset ID
`get_labels`(changeset)	Provides the changeset labels
`is_always_run`(changeset)	Provides the changeset alwaysRun value
`is_run_on_change`(changeset)	Provides the changeset runOnChange value

Database attributes

These are functions available to you after importing liquibase_database file and they are functions to access, or return, database attributes. The database is always the input parameter for these attributes.

Function	Return
`get_database_product_name`(database)	Provides the database product name
`get_database_product_version`(database)	Provides the database product version
`get_default_schema_name`(database)	Provides the default schema for this database
`get_short_name`(database)	Provides the database short name

JSON utilities

These are functions available to you after importing the liquibase_json file and they are functions to access, or return, JSON attributes. These are functions to parse a JSON snapshot and access, or return, Dict objects.

Function	Return	Input Parameter
`get_column`(snapshot, table_name, column_name)	Provides the specified Column Dict object for a table	`snapshot`: the snapshot to parse `table_name`: the name of the table to search for `column_name`: the name of the column to search for
`get_column_size`(column)	Provides the specified Column's size	`column`: the Column Dict object
`get_column_type_name`(column)	Provides the specified Column's type name	`column`: the Column Dict object
`get_columns`(snapshot, table_name)	Provides a list of Column Dict objects for a table such as a JSON serialized representation of the Liquibase internal DatabaseObject class. Example output: {'column': {'name': 'name', 'nullable': True, 'order': '1!{java.lang.Integer}', 'relation': 'liquibase.structure.core.Table#0eab104', 'snapshotId': '0eab105', 'type': {'characterOctetLength': '20!{java.lang.Integer}', 'columnSize': '20!{java.lang.Integer}', 'columnSizeUnit': 'BYTE!{liquibase.structure.core.DataType$ColumnSizeUnit}', 'dataTypeId': '1!{java.lang.Integer}', 'radix': '10!{java.lang.Integer}', 'typeName': 'bpchar'}}}	`snapshot`: the snapshot to parse `table_name`: the name of the table to search for
`get_indexes`(snapshot, table_name)	Provides a List of Index Dict objects for a table	`snapshot`: the snapshot to parse `table_name`: the name of the table to search for
`get_primary_key`(snapshot, table_name)	Provides a Primary Key Dict object for a table	`snapshot`: the snapshot to parse `table_name`: the name of the table to search for
`get_table`(snapshot, table_name)	Provides a list of Table Dict objects	`snapshot`: the snapshot to parse `table_name`: the name of the table to search for
`get_tables`(snapshot)	Provides a list of Table Dict objects	`snapshot`: the snapshot to parse

Liquibase utilities

Utilities are general script helpers that retrieve content frequently searched for.

Function	Return	Input Parameter
`generate_sql`(change)	Generates a specific SQL Change Type change and database Example: changes = liquibase_utilities.get_changes() # get the changes we're looking at sql = liquibase_utilities.generate_sql(change[0]) # get the first change in the list if "something bad" in sql: status.fired = True sys.exit(1) # exit from the check	change: the change to generate SQL from return: the SQL of the change
`get_arg`(name)	Return the value of a script argument	name: the argument to find return: the value of the argument
`get_binding`(key)	Access the binding object at the given key	key: the binding to access return: the binding
`get_cache`(key, default_value)	Returns the stored key/value pairs held by a dict object that are available between script executions. For example, you can count the number of times a check triggers by adding a counter that updates for each feature. If there is no current value, then put the default value.	key: the look up key default_value: the value to put for the key if no value present return: the current value or the default
`get_changes`()	Returns the set of changes that the check is actively examining	return: the liquibase change objects
`get_changeset`()	Returns the changeset object Liquibase is actively examining	return: the liquibase change set object
`get_column_type`(database_object)	Get the data type of the column of a database object. examples include: varchar, integer, etc.	database_object: the database object return: the type of the column, or None if the database object is not a column
`get_database`()	Get the liquibase database object	return: the liquibase database object
`get_database_object`()	Return the DatabaseObject that is being referenced in a database-scoped check	return: the current database object being checked
`get_database_snapshot`()	Return the DatabaseSnapshot as a String	return: the database snapshot string
`get_dbutil`()	Return the dbutil object used to check for object existence or to snapshot the DatabaseObject and return it	return: the db_util object
`get_logger`()	Get the liquibase logger	return: the liquibase logger
`get_object_type_name`(database_object)	Get the object type string of a given database object	database_object: The database_object to return the type for return: the type as a string
`get_script_message`()	Get the message for the script	return: the message
`get_script_path`()	Return the path of the script	return: the path of the script
`get_snapshot`()	Return the snapshot as a JSON object.	return: The snapshot JSON object or None if no snapshot is available
`get_status`()	Return the Status object which will be used to set the check fired status and return a message	return: the status object
`has`(object_type, schema_name, object_name)	Returns `true` if there is an object of this type and name in the schema	object_type: the object type schema_name: the schema name object_name: the object name return: `true` if there is an object that matches this description, `false` otherwise
`has_relation`(object_type, object_name, relation_type, relation_schema_name, relation_name)	Returns `true` if there is an object of this type that has a relation object that matches the relation type, schema, and name	object_type: the object type object_name: the object name relation_type: the type of relation (Table or View) relation_schema_name: the schema of the relation object relation_name: the name of the relation return: Returns `true` if there is an object of this type that has a relation object that matches the relation type, schema, and name. Returns `false` if no items match the provided criteria.
`is_catalog`(database_object)	Check if the database object is a catalog	database_object: the database object to check return: `true` if the object is a catalog, `false` otherwise
`is_check_constraint`(database_object)	Check if the database object is a check constraint	database_object: the database object to check return: `true` if the object is a check constraint, `false` otherwise
`is_column`(database_object)	Check if the database object is a column	database_object: the database object to check return: `true` if the object is a column, `false` otherwise
`is_database_package`(database_object)	Check if the database object is a database package	database_object: the database object to check return: `true` if the object is a database package, `false` otherwise
`is_database_package_body`(database_object)	Check if the database object is a database package body	database_object: the database object to check return: `true` if the object is a database package body, `false` otherwise
`is_foreign_key`(database_object)	Check if the database object is a foreign key	database_object: the database object to check return: `true` if the object is a foreign key, `false` otherwise
`is_function`(database_object)	Check if the database object is a function	database_object: the database object to check return: `true` if the object is a function, `false` otherwise
`is_index`(database_object)	Check if the database object is an index	database_object: the database object to check return: `true` if the object is a index, `false` otherwise
`is_primary_key`(database_object)	Check if the database object is a primary key	database_object: the database object to check return: `true` if the object is a primary key, `false` otherwise
`is_schema`(database_object)	Check if the database object is a schema	database_object: the database object to check return: `true` if the object is a schema, `false` otherwise
`is_sequence`(database_object)	Check if the database object is a sequence	database_object: the database object to check return: `true` if the object is a sequence, `false` otherwise
`is_stored_database_logic`(database_object)	Check if the database object is stored database logic	database_object: the database object to check return: `true` if the object is stored database logic, `false` otherwise
`is_stored_procedure`(database_object)	Check if the database object is a stored procedure	database_object: the database object to check return: `true` if the object is a stored procedure, `false` otherwise
`is_synonym`(database_object)	Check if the database object is a synonym	database_object: the database object to check return: `true` if the object is a synonym, `false` otherwise
`is_table`(database_object)	Check if the database object is a table	database_object: the database object to check return: `true` if the object is a table, `false` otherwise
`is_trigger`(database_object)	Check if the database object is a trigger	database_object: the database object to check return: `true` if the object is a trigger, `false` otherwise
`is_unique_constraint`(database_object)	Check if the database object is a unique constraint	database_object: the database object to check return: `true` if the object is a unique constraint, `false` otherwise
`is_view`(database_object)	Check if the database object is a view	database_object: the database object to check return: `true` if the object is a view, `false` otherwise
`put_cache`(key, value)	Places the stored key/value pairs held by a dict object that are available between script executions.	key The key to use value The value to put in the cache
`query_for_list`(SQL, SQL_file, end_delimiter)	Execute a SQL statement or script	SQL: the SQL to execute SQL_file: the SQL file to execute end_delimiter: the end delimiter to use return: the results of the SQL as a list
`snapshot_object`(object_type, object_name, relation_type, schema_name, relation_name)	Provides a Liquibase model object that represents a database object	object_type: the type of the object, like Table object_name: the objects name relation_type: a type of relation that we need to snapshot to access the object schema_name: the schema for the relation relation_name: the name of the relation return: the liquibase model for the database object
`split_SQL`(SQL_string, strip_comments_flag, end_delimiter, changeset)	Provides an array of SQL lines	SQL_string: the SQL to process strip_comments_flag: `true` to strip out comments end_delimiter: the end delimiter to use while processing the SQL changeset: the change set associated with the SQL return: An array of SQL lines
`split_statements`(SQL_string)	Split a string of SQL into individual statements	SQL_string: the SQL string to split return: the list of SQL strings
`strip_comments`(SQL_string)	Strip comments from a SQL string	SQL_string: the SQL to strip return: the SQL string with comments removed
`tokenize`(statement)	Tokenize a statement which was created by SQLparse and returns a list	statement: the statement to tokenize return: the tokenized statement as a list

Constants

**Constant Methods**
__init__(self)
__setattr__(self, name, value)

**Constant data descriptors**
__dict__
__weakref__

Script Constants

**ScriptConstant data descriptors**
__dict__
__weakref__

**ScriptConstant data and other attribute definitions**
ARGS_SUFFIX = '_arg_binding'
CACHE_BINDING = 'cache_binding'
CHANGESET_BINDING = 'changeSet_binding'
CHANGES_BINDING = 'changes_binding'
DATABASE_BINDING = 'database_binding'
DATABASE_OBJECT_BINDING = 'databaseObject_binding'
DATABASE_SNAPSHOT_BINDING = 'databaseSnapshot_binding'
DBUTIL_BINDING = 'dbutil_binding'
LOGGER_BINDING = 'logger_binding'
SCRIPT_MESSAGE_BINDING = 'scriptMessage_binding'
SCRIPT_PATH_BINDING = 'script_path_binding'
STATUS_BINDING = 'status_binding'