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SchemaMigrations

Manage the schema migrations in the database. It provides methods to create the schema_migrations table, check its existence, set the baseline version, and retrieve migration details.

Source code in pum/schema_migrations.py 
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class SchemaMigrations:
    """Manage the schema migrations in the database.
    It provides methods to create the schema_migrations table, check its existence,
    set the baseline version, and retrieve migration details.
    """

    def __init__(self, config: PumConfig) -> None:
        """Initialize the SchemaMigrations class with a database connection and configuration.

        Args:
            config (PumConfig): An instance of the PumConfig class containing configuration settings for the PUM system.

        """
        self.config = config
        self.migration_table_identifier = psycopg.sql.SQL(".").join(
            [
                psycopg.sql.Identifier(self.config.config.pum.migration_table_schema),
                psycopg.sql.Identifier(MIGRATION_TABLE_NAME),
            ]
        )

    def exists(self, connection: psycopg.Connection) -> bool:
        """Check if the schema_migrations information table exists.

        Args:
            connection: The database connection to check for the existence of the table.

        Returns:
            bool: True if the table exists, False otherwise.

        """
        query = psycopg.sql.SQL(
            """
        SELECT EXISTS (
            SELECT 1
            FROM information_schema.tables
            WHERE table_name = 'pum_migrations' AND table_schema = {schema}
        );
        """
        )

        parameters = {
            "schema": psycopg.sql.Literal(self.config.config.pum.migration_table_schema),
        }

        cursor = SqlContent(query).execute(connection, parameters=parameters)
        return cursor.fetchone()[0]

    def exists_in_other_schemas(self, connection: psycopg.Connection) -> list[str]:
        """Check if the schema_migrations information table exists in other schemas.

        Args:
            connection: The database connection to check for the existence of the table.

        Returns:
            List[str]: List of schemas where the table exists.

        """
        query = psycopg.sql.SQL(
            """
            SELECT table_schema
            FROM information_schema.tables
            WHERE table_name = 'pum_migrations' AND table_schema != {schema}
        """
        )

        parameters = {
            "schema": psycopg.sql.Literal(self.config.config.pum.migration_table_schema),
        }
        cursor = SqlContent(query).execute(connection, parameters=parameters)
        return [row[0] for row in cursor.fetchall()]

    def create(
        self,
        connection: psycopg.Connection,
        *,
        allow_multiple_schemas: bool = False,
        commit: bool = False,
    ) -> None:
        """Create the schema_migrations information table
        Args:
            connection: The database connection to create the table.
            commit: If true, the transaction is committed. The default is false.
            allow_multiple_schemas: If true, several pum_migrations tables are allowed in
                distinct schemas. Default is false.
        """
        if self.exists(connection):
            logger.info(
                f"{self.config.config.pum.migration_table_schema}.pum_migrations table already exists."
            )
            return

        if not allow_multiple_schemas and len(self.exists_in_other_schemas(connection)) > 0:
            raise PumException(
                f"Another {self.config.config.pum.migration_table_schema}.{self.config.config.pum.migration_table_name} table exists in another schema (). "
                "Please use the allow_multiple_schemas option to create a new one."
            )

        # Create the schema if it doesn't exist
        parameters = {
            "version": psycopg.sql.Literal(MIGRATION_TABLE_VERSION),
            "schema": psycopg.sql.Identifier(self.config.config.pum.migration_table_schema),
            "table": self.migration_table_identifier,
        }

        create_schema_query = None
        if self.config.config.pum.migration_table_schema != "public":
            create_schema_query = psycopg.sql.SQL("CREATE SCHEMA IF NOT EXISTS {schema};")

        create_table_query = psycopg.sql.SQL(
            """CREATE TABLE IF NOT EXISTS {table}
            (
            id uuid DEFAULT gen_random_uuid() PRIMARY KEY,
            date_installed timestamp without time zone NOT NULL DEFAULT now(),
            module character varying(50), -- TODO: NOT NULL,
            version character varying(50) NOT NULL,
            beta_testing boolean NOT NULL DEFAULT false,
            changelog_files text[],
            parameters jsonb,
            migration_table_version character varying(50) NOT NULL DEFAULT {version}
            );
        """
        )

        comment_query = psycopg.sql.SQL(
            "COMMENT ON TABLE {table} IS 'version: 1 --  schema_migration table version';"
        )

        if create_schema_query:
            SqlContent(create_schema_query).execute(connection, parameters=parameters)
        SqlContent(create_table_query).execute(connection, parameters=parameters)
        SqlContent(comment_query).execute(connection, parameters=parameters)

        logger.info(f"Created {parameters['schema']}.{parameters['table']} table")

        if commit:
            connection.commit()

    def set_baseline(
        self,
        connection: psycopg.Connection,
        version: packaging.version.Version | str,
        changelog_files: list[str] | None = None,
        parameters: dict | None = None,
        *,
        beta_testing: bool = False,
        commit: bool = False,
    ) -> None:
        """Set the baseline into the migration table.

        Args:
            connection: The database connection to set the baseline version.
            version: The version of the current database to set in the information.
            changelog_files: The list of changelog files that were applied.
            parameters: The parameters used in the migration.
            beta_testing: If true, the baseline is set to beta testing mode. The default is false.
            commit: If true, the transaction is committed. The default is False.

        """
        if isinstance(version, packaging.version.Version):
            version = str(version)
        pattern = re.compile(r"^\d+\.\d+\.\d+$")
        if not re.match(pattern, version):
            raise ValueError(f"Wrong version format: {version}. Must be x.x.x")

        current = self.baseline(connection=connection)
        if current and current >= version:
            raise PumException(f"Cannot set baseline {version} as it is already set at {current}.")

        code = psycopg.sql.SQL("""
INSERT INTO {table} (
    version,
    beta_testing,
    migration_table_version,
    changelog_files,
    parameters
) VALUES (
    {version},
    {beta_testing},
    {migration_table_version},
    {changelog_files},
    {parameters}
);""")

        query_parameters = {
            "table": self.migration_table_identifier,
            "version": psycopg.sql.Literal(version),
            "beta_testing": psycopg.sql.Literal(beta_testing),
            "migration_table_version": psycopg.sql.Literal(MIGRATION_TABLE_VERSION),
            "changelog_files": psycopg.sql.Literal(changelog_files or []),
            "parameters": psycopg.sql.Literal(json.dumps(parameters or {})),
        }

        logger.info(
            f"Setting baseline version {version} in {self.config.config.pum.migration_table_schema}.{MIGRATION_TABLE_NAME} table"
        )
        SqlContent(code).execute(connection, parameters=query_parameters, commit=commit)

    def baseline(self, connection: psycopg.Connection) -> str | None:
        """Return the baseline version from the migration table.

        Args:
            connection: psycopg.Connection
                The database connection to get the baseline version.

        Returns:
            str: The baseline version.

        """

        if not self.exists(connection=connection):
            return None

        query = psycopg.sql.SQL(
            """
            SELECT version
            FROM {table}
            WHERE id = (
                SELECT id
                FROM {table}
                ORDER BY version DESC, date_installed DESC
                LIMIT 1
            )
        """
        )

        parameters = {
            "table": self.migration_table_identifier,
        }

        cursor = SqlContent(query).execute(connection, parameters=parameters)
        row = cursor.fetchone()
        if row is None:
            return None
        return row[0]

    def migration_details(self, connection: psycopg.Connection, version: str | None = None) -> dict:
        """Return the migration details from the migration table.

        Args:
            connection:
                The database connection to get the migration details.
            version:
                The version of the migration to get details for.
                If None, last migration is returned.

        Returns:
            dict: The migration details.

        """
        query = None
        if version is None:
            query = psycopg.sql.SQL(
                """
                SELECT *
                FROM {table}
                WHERE id = (
                        SELECT id
                        FROM {table}
                        ORDER BY version DESC, date_installed DESC
                        LIMIT 1
                    )
                ORDER BY date_installed DESC
            """
            )

            parameters = {
                "table": self.migration_table_identifier,
            }
        else:
            query = psycopg.sql.SQL(
                """
                SELECT *
                FROM {table}
                WHERE version = {version}
            """
            )

            parameters = {
                "table": self.migration_table_identifier,
                "version": psycopg.sql.Literal(version),
            }

        cursor = SqlContent(query).execute(connection, parameters=parameters)
        row = cursor.fetchone()
        if row is None:
            return None
        return dict(zip([desc[0] for desc in cursor.description], row, strict=False))

__init__ 

__init__(config: PumConfig) -> None

Initialize the SchemaMigrations class with a database connection and configuration.

Parameters:

Name Type Description Default
config PumConfig

An instance of the PumConfig class containing configuration settings for the PUM system.

 required
Source code in pum/schema_migrations.py 
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def __init__(self, config: PumConfig) -> None:
    """Initialize the SchemaMigrations class with a database connection and configuration.

    Args:
        config (PumConfig): An instance of the PumConfig class containing configuration settings for the PUM system.

    """
    self.config = config
    self.migration_table_identifier = psycopg.sql.SQL(".").join(
        [
            psycopg.sql.Identifier(self.config.config.pum.migration_table_schema),
            psycopg.sql.Identifier(MIGRATION_TABLE_NAME),
        ]
    )

baseline 

baseline(connection: Connection) -> str | None

Return the baseline version from the migration table.

Parameters:

Name Type Description Default
connection Connection

psycopg.Connection The database connection to get the baseline version.

 required

Returns:

Name Type Description
str str | None

The baseline version.
Source code in pum/schema_migrations.py 
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def baseline(self, connection: psycopg.Connection) -> str | None:
    """Return the baseline version from the migration table.

    Args:
        connection: psycopg.Connection
            The database connection to get the baseline version.

    Returns:
        str: The baseline version.

    """

    if not self.exists(connection=connection):
        return None

    query = psycopg.sql.SQL(
        """
        SELECT version
        FROM {table}
        WHERE id = (
            SELECT id
            FROM {table}
            ORDER BY version DESC, date_installed DESC
            LIMIT 1
        )
    """
    )

    parameters = {
        "table": self.migration_table_identifier,
    }

    cursor = SqlContent(query).execute(connection, parameters=parameters)
    row = cursor.fetchone()
    if row is None:
        return None
    return row[0]

create 

create(connection: Connection, *, allow_multiple_schemas: bool = False, commit: bool = False) -> None

Create the schema_migrations information table Args: connection: The database connection to create the table. commit: If true, the transaction is committed. The default is false. allow_multiple_schemas: If true, several pum_migrations tables are allowed in distinct schemas. Default is false.

Source code in pum/schema_migrations.py 
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def create(
    self,
    connection: psycopg.Connection,
    *,
    allow_multiple_schemas: bool = False,
    commit: bool = False,
) -> None:
    """Create the schema_migrations information table
    Args:
        connection: The database connection to create the table.
        commit: If true, the transaction is committed. The default is false.
        allow_multiple_schemas: If true, several pum_migrations tables are allowed in
            distinct schemas. Default is false.
    """
    if self.exists(connection):
        logger.info(
            f"{self.config.config.pum.migration_table_schema}.pum_migrations table already exists."
        )
        return

    if not allow_multiple_schemas and len(self.exists_in_other_schemas(connection)) > 0:
        raise PumException(
            f"Another {self.config.config.pum.migration_table_schema}.{self.config.config.pum.migration_table_name} table exists in another schema (). "
            "Please use the allow_multiple_schemas option to create a new one."
        )

    # Create the schema if it doesn't exist
    parameters = {
        "version": psycopg.sql.Literal(MIGRATION_TABLE_VERSION),
        "schema": psycopg.sql.Identifier(self.config.config.pum.migration_table_schema),
        "table": self.migration_table_identifier,
    }

    create_schema_query = None
    if self.config.config.pum.migration_table_schema != "public":
        create_schema_query = psycopg.sql.SQL("CREATE SCHEMA IF NOT EXISTS {schema};")

    create_table_query = psycopg.sql.SQL(
        """CREATE TABLE IF NOT EXISTS {table}
        (
        id uuid DEFAULT gen_random_uuid() PRIMARY KEY,
        date_installed timestamp without time zone NOT NULL DEFAULT now(),
        module character varying(50), -- TODO: NOT NULL,
        version character varying(50) NOT NULL,
        beta_testing boolean NOT NULL DEFAULT false,
        changelog_files text[],
        parameters jsonb,
        migration_table_version character varying(50) NOT NULL DEFAULT {version}
        );
    """
    )

    comment_query = psycopg.sql.SQL(
        "COMMENT ON TABLE {table} IS 'version: 1 --  schema_migration table version';"
    )

    if create_schema_query:
        SqlContent(create_schema_query).execute(connection, parameters=parameters)
    SqlContent(create_table_query).execute(connection, parameters=parameters)
    SqlContent(comment_query).execute(connection, parameters=parameters)

    logger.info(f"Created {parameters['schema']}.{parameters['table']} table")

    if commit:
        connection.commit()

exists 

exists(connection: Connection) -> bool

Check if the schema_migrations information table exists.

Parameters:

Name Type Description Default
connection Connection

The database connection to check for the existence of the table.

 required

Returns:

Name Type Description
bool bool

True if the table exists, False otherwise.
Source code in pum/schema_migrations.py 
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def exists(self, connection: psycopg.Connection) -> bool:
    """Check if the schema_migrations information table exists.

    Args:
        connection: The database connection to check for the existence of the table.

    Returns:
        bool: True if the table exists, False otherwise.

    """
    query = psycopg.sql.SQL(
        """
    SELECT EXISTS (
        SELECT 1
        FROM information_schema.tables
        WHERE table_name = 'pum_migrations' AND table_schema = {schema}
    );
    """
    )

    parameters = {
        "schema": psycopg.sql.Literal(self.config.config.pum.migration_table_schema),
    }

    cursor = SqlContent(query).execute(connection, parameters=parameters)
    return cursor.fetchone()[0]

exists_in_other_schemas 

exists_in_other_schemas(connection: Connection) -> list[str]

Check if the schema_migrations information table exists in other schemas.

Parameters:

Name Type Description Default
connection Connection

The database connection to check for the existence of the table.

 required

Returns:

Type Description
list[str]

List[str]: List of schemas where the table exists.
Source code in pum/schema_migrations.py 
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def exists_in_other_schemas(self, connection: psycopg.Connection) -> list[str]:
    """Check if the schema_migrations information table exists in other schemas.

    Args:
        connection: The database connection to check for the existence of the table.

    Returns:
        List[str]: List of schemas where the table exists.

    """
    query = psycopg.sql.SQL(
        """
        SELECT table_schema
        FROM information_schema.tables
        WHERE table_name = 'pum_migrations' AND table_schema != {schema}
    """
    )

    parameters = {
        "schema": psycopg.sql.Literal(self.config.config.pum.migration_table_schema),
    }
    cursor = SqlContent(query).execute(connection, parameters=parameters)
    return [row[0] for row in cursor.fetchall()]

migration_details 

migration_details(connection: Connection, version: str | None = None) -> dict

Return the migration details from the migration table.

Parameters:

Name Type Description Default
connection Connection

The database connection to get the migration details.

 required
version str | None

The version of the migration to get details for. If None, last migration is returned.

 None

Returns:

Name Type Description
dict dict

The migration details.
Source code in pum/schema_migrations.py 
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def migration_details(self, connection: psycopg.Connection, version: str | None = None) -> dict:
    """Return the migration details from the migration table.

    Args:
        connection:
            The database connection to get the migration details.
        version:
            The version of the migration to get details for.
            If None, last migration is returned.

    Returns:
        dict: The migration details.

    """
    query = None
    if version is None:
        query = psycopg.sql.SQL(
            """
            SELECT *
            FROM {table}
            WHERE id = (
                    SELECT id
                    FROM {table}
                    ORDER BY version DESC, date_installed DESC
                    LIMIT 1
                )
            ORDER BY date_installed DESC
        """
        )

        parameters = {
            "table": self.migration_table_identifier,
        }
    else:
        query = psycopg.sql.SQL(
            """
            SELECT *
            FROM {table}
            WHERE version = {version}
        """
        )

        parameters = {
            "table": self.migration_table_identifier,
            "version": psycopg.sql.Literal(version),
        }

    cursor = SqlContent(query).execute(connection, parameters=parameters)
    row = cursor.fetchone()
    if row is None:
        return None
    return dict(zip([desc[0] for desc in cursor.description], row, strict=False))

set_baseline 

set_baseline(connection: Connection, version: Version | str, changelog_files: list[str] | None = None, parameters: dict | None = None, *, beta_testing: bool = False, commit: bool = False) -> None

Set the baseline into the migration table.

Parameters:

Name Type Description Default
connection Connection

The database connection to set the baseline version.

 required
version Version | str

The version of the current database to set in the information.

 required
changelog_files list[str] | None

The list of changelog files that were applied.

 None
parameters dict | None

The parameters used in the migration.

 None
beta_testing bool

If true, the baseline is set to beta testing mode. The default is false.

 False
commit bool

If true, the transaction is committed. The default is False.

 False
Source code in pum/schema_migrations.py 
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    def set_baseline(
        self,
        connection: psycopg.Connection,
        version: packaging.version.Version | str,
        changelog_files: list[str] | None = None,
        parameters: dict | None = None,
        *,
        beta_testing: bool = False,
        commit: bool = False,
    ) -> None:
        """Set the baseline into the migration table.

        Args:
            connection: The database connection to set the baseline version.
            version: The version of the current database to set in the information.
            changelog_files: The list of changelog files that were applied.
            parameters: The parameters used in the migration.
            beta_testing: If true, the baseline is set to beta testing mode. The default is false.
            commit: If true, the transaction is committed. The default is False.

        """
        if isinstance(version, packaging.version.Version):
            version = str(version)
        pattern = re.compile(r"^\d+\.\d+\.\d+$")
        if not re.match(pattern, version):
            raise ValueError(f"Wrong version format: {version}. Must be x.x.x")

        current = self.baseline(connection=connection)
        if current and current >= version:
            raise PumException(f"Cannot set baseline {version} as it is already set at {current}.")

        code = psycopg.sql.SQL("""
INSERT INTO {table} (
    version,
    beta_testing,
    migration_table_version,
    changelog_files,
    parameters
) VALUES (
    {version},
    {beta_testing},
    {migration_table_version},
    {changelog_files},
    {parameters}
);""")

        query_parameters = {
            "table": self.migration_table_identifier,
            "version": psycopg.sql.Literal(version),
            "beta_testing": psycopg.sql.Literal(beta_testing),
            "migration_table_version": psycopg.sql.Literal(MIGRATION_TABLE_VERSION),
            "changelog_files": psycopg.sql.Literal(changelog_files or []),
            "parameters": psycopg.sql.Literal(json.dumps(parameters or {})),
        }

        logger.info(
            f"Setting baseline version {version} in {self.config.config.pum.migration_table_schema}.{MIGRATION_TABLE_NAME} table"
        )
        SqlContent(code).execute(connection, parameters=query_parameters, commit=commit)