patroni.psycopg module

Abstraction layer for psycopg module.

This module is able to handle both pyscopg2 and psycopg, and it exposes a common interface for both. psycopg2 takes precedence. psycopg will only be used if psycopg2 is either absent or older than 2.5.4.

exception patroni.psycopg.DatabaseError

Bases: psycopg2.Error

Error related to the database engine.

exception patroni.psycopg.Error

Bases: Exception

Base class for error exceptions.

__init__(*args, **kwargs)

Initialize self. See help(type(self)) for accurate signature.

cursor

The cursor that raised the exception, if available, else None

diag

A Diagnostics object to get further information about the error

pgcode

The error code returned by the backend, if available, else None

pgerror

The error message returned by the backend, if available, else None

exception patroni.psycopg.OperationalError

Bases: psycopg2.DatabaseError

Error related to database operation (disconnect, memory allocation etc).

exception patroni.psycopg.ProgrammingError

Bases: psycopg2.DatabaseError

Error related to database programming (SQL error, table not found etc).

patroni.psycopg.connect(*args: Any, **kwargs: Any) → Union[connection, Connection[Any]]

Get a connection to the database.

Note

The connection will have autocommit enabled.

It also enforces search_path=pg_catalog for non-replication connections to mitigate security issues as Patroni relies on superuser connections.

Parameters

  • args – positional arguments to call connect() function from psycopg module.

  • kwargs – keyword arguments to call connect() function from psycopg module.

Returns

a connection to the database. Can be either a psycopg.Connection if using psycopg, or a psycopg2.extensions.connection if using psycopg2.

patroni.psycopg.parse_conninfo(value: str, fallback: Callable[[str], Optional[Dict[str, str]]]) → Optional[Dict[str, str]]

Parse connection string.

Parameters

  • value – value to parse.

  • fallback – a function to use if we have only very old psycopg2, which doesn’t expose parse_dsn().

Returns

a dict object, or None if failed to parse.

patroni.psycopg.quote_ident(value: Any, conn: Optional[Union[cursor, connection, Connection[Any]]] = None) → str

Quote value as a SQL identifier.

Parameters

  • value – value to be quoted.

  • conn – connection to evaluate the returning string into. Can be either a psycopg.Connection if using psycopg, or a psycopg2.extensions.connection if using psycopg2.

Returns

value quoted as a SQL identifier.

patroni.psycopg.quote_literal(value: Any, conn: Optional[Any] = None) → str

Quote value as a SQL literal.

Note

value is quoted through psycopg2 adapters.

Parameters

  • value – value to be quoted.

  • conn – if a connection is given then quote_literal() checks if any special handling based on server parameters needs to be applied to value before quoting it as a SQL literal.

Returns

value quoted as a SQL literal.