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Source code for airflow.providers.postgres.hooks.postgres

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from __future__ import annotations

import os
from collections.abc import Mapping
from contextlib import closing
from copy import deepcopy
from typing import TYPE_CHECKING, Any, Literal, Protocol, TypeAlias, cast, overload

import psycopg2
import psycopg2.extensions
import psycopg2.extras
from more_itertools import chunked
from psycopg2.extras import DictCursor, NamedTupleCursor, RealDictCursor, execute_batch
from sqlalchemy.engine import URL

from airflow.exceptions import (
    AirflowException,
    AirflowOptionalProviderFeatureException,
)
from airflow.providers.common.sql.hooks.sql import DbApiHook
from airflow.providers.postgres.dialects.postgres import PostgresDialect

[docs] USE_PSYCOPG3: bool
try: import psycopg as psycopg # needed for patching in unit tests import sqlalchemy from packaging.version import Version
[docs] sqlalchemy_version = Version(sqlalchemy.__version__)
is_sqla2 = (sqlalchemy_version.major, sqlalchemy_version.minor, sqlalchemy_version.micro) >= (2, 0, 0) USE_PSYCOPG3 = is_sqla2 # implicitly includes `and bool(psycopg)` since the import above succeeded except (ImportError, ModuleNotFoundError): USE_PSYCOPG3 = False if USE_PSYCOPG3: from psycopg.rows import dict_row, namedtuple_row from psycopg.types.json import register_default_adapters if TYPE_CHECKING: from pandas import DataFrame as PandasDataFrame from polars import DataFrame as PolarsDataFrame from airflow.providers.common.sql.dialects.dialect import Dialect from airflow.providers.openlineage.sqlparser import DatabaseInfo if USE_PSYCOPG3: from psycopg.errors import Diagnostic try: from airflow.sdk import Connection except ImportError: from airflow.models.connection import Connection # type: ignore[assignment]
[docs] CursorType: TypeAlias = DictCursor | RealDictCursor | NamedTupleCursor
[docs] CursorRow: TypeAlias = dict[str, Any] | tuple[Any, ...]
[docs] class CompatConnection(Protocol): """Protocol for type hinting psycopg2 and psycopg3 connection objects."""
[docs] def cursor(self, *args, **kwargs) -> Any: ...
[docs] def commit(self) -> None: ...
[docs] def close(self) -> None: ...
# Context manager support
[docs] def __enter__(self) -> CompatConnection: ...
[docs] def __exit__(self, exc_type: Any, exc_val: Any, exc_tb: Any) -> None: ...
# Common properties @property
[docs] def notices(self) -> list[Any]: ...
# psycopg3 specific (optional) @property
[docs] def adapters(self) -> Any: ...
@property
[docs] def row_factory(self) -> Any: ...
# Optional method for psycopg3
[docs] def add_notice_handler(self, handler: Any) -> None: ...
[docs] class PostgresHook(DbApiHook): """ Interact with Postgres. You can specify ssl parameters in the extra field of your connection as ``{"sslmode": "require", "sslcert": "/path/to/cert.pem", etc}``. Also, you can choose cursor as ``{"cursor": "dictcursor"}``. Refer to the psycopg2.extras or psycopg.rows for more details. Note: For Redshift, use keepalives_idle in the extra connection parameters and set it to less than 300 seconds. Note: For AWS IAM authentication, use iam in the extra connection parameters and set it to true. Leave the password field empty. This will use the "aws_default" connection to get the temporary token unless you override in extras. extras example: ``{"iam":true, "aws_conn_id":"my_aws_conn"}`` For Redshift, also use redshift in the extra connection parameters and set it to true. The cluster-identifier is extracted from the beginning of the host field, so is optional. It can however be overridden in the extra field. extras example: ``{"iam":true, "redshift":true, "cluster-identifier": "my_cluster_id"}`` For Redshift Serverless, use redshift-serverless in the extra connection parameters and set it to true. The workgroup-name is extracted from the beginning of the host field, so is optional. It can however be overridden in the extra field. extras example: ``{"iam":true, "redshift-serverless":true, "workgroup-name": "my_serverless_workgroup"}`` :param postgres_conn_id: The :ref:`postgres conn id <howto/connection:postgres>` reference to a specific postgres database. :param options: Optional. Specifies command-line options to send to the server at connection start. For example, setting this to ``-c search_path=myschema`` sets the session's value of the ``search_path`` to ``myschema``. :param enable_log_db_messages: Optional. If enabled logs database messages sent to the client during the session. To avoid a memory leak psycopg2 only saves the last 50 messages. For details, see: `PostgreSQL logging configuration parameters <https://www.postgresql.org/docs/current/runtime-config-logging.html>`__ """
[docs] conn_name_attr = "postgres_conn_id"
[docs] default_conn_name = "postgres_default"
[docs] default_client_log_level = "warning"
[docs] default_connector_version: int = 2
[docs] conn_type = "postgres"
[docs] hook_name = "Postgres"
[docs] supports_autocommit = True
[docs] supports_executemany = True
[docs] ignored_extra_options = { "iam", "redshift", "redshift-serverless", "cursor", "cluster-identifier", "workgroup-name", "aws_conn_id", "sqlalchemy_scheme", "sqlalchemy_query", }
def __init__( self, *args, options: str | None = None, enable_log_db_messages: bool = False, **kwargs ) -> None: super().__init__(*args, **kwargs)
[docs] self.conn: CompatConnection | None = None
[docs] self.database: str | None = kwargs.pop("database", None)
[docs] self.options = options
[docs] self.enable_log_db_messages = enable_log_db_messages
@staticmethod def __cast_nullable(value, dst_type: type) -> Any: return dst_type(value) if value is not None else None @property
[docs] def sqlalchemy_url(self) -> URL: conn = self.connection query = conn.extra_dejson.get("sqlalchemy_query", {}) if not isinstance(query, dict): raise AirflowException("The parameter 'sqlalchemy_query' must be of type dict!") return URL.create( drivername="postgresql+psycopg" if USE_PSYCOPG3 else "postgresql", username=self.__cast_nullable(conn.login, str), password=self.__cast_nullable(conn.password, str), host=self.__cast_nullable(conn.host, str), port=self.__cast_nullable(conn.port, int), database=self.__cast_nullable(self.database, str) or self.__cast_nullable(conn.schema, str), query=query, )
@property
[docs] def dialect_name(self) -> str: return "postgresql"
@property
[docs] def dialect(self) -> Dialect: return PostgresDialect(self)
def _notice_handler(self, notice: Diagnostic): """Handle notices from the database and log them.""" self.log.info(str(notice.message_primary).strip()) def _get_cursor(self, raw_cursor: str) -> CursorType: _cursor = raw_cursor.lower() if USE_PSYCOPG3: if _cursor == "dictcursor": return dict_row if _cursor == "namedtuplecursor": return namedtuple_row if _cursor == "realdictcursor": raise AirflowException( "realdictcursor is not supported with psycopg3. Use dictcursor instead." ) valid_cursors = "dictcursor, namedtuplecursor" raise ValueError(f"Invalid cursor passed {_cursor}. Valid options are: {valid_cursors}") cursor_types = { "dictcursor": psycopg2.extras.DictCursor, "realdictcursor": psycopg2.extras.RealDictCursor, "namedtuplecursor": psycopg2.extras.NamedTupleCursor, } if _cursor in cursor_types: return cursor_types[_cursor] valid_cursors = ", ".join(cursor_types.keys()) raise ValueError(f"Invalid cursor passed {_cursor}. Valid options are: {valid_cursors}") def _generate_cursor_name(self): """Generate a unique name for server-side cursor.""" import uuid return f"airflow_cursor_{uuid.uuid4().hex}"
[docs] def get_conn(self) -> CompatConnection: """Establish a connection to a postgres database.""" conn = deepcopy(self.connection) if conn.extra_dejson.get("iam", False): login, password, port = self.get_iam_token(conn) conn.login = cast("Any", login) conn.password = cast("Any", password) conn.port = cast("Any", port) conn_args: dict[str, Any] = { "host": conn.host, "user": conn.login, "password": conn.password, "dbname": self.database or conn.schema, "port": conn.port, } if self.options: conn_args["options"] = self.options # Add extra connection arguments for arg_name, arg_val in conn.extra_dejson.items(): if arg_name not in self.ignored_extra_options: conn_args[arg_name] = arg_val if USE_PSYCOPG3: from psycopg.connection import Connection as pgConnection raw_cursor = conn.extra_dejson.get("cursor") if raw_cursor: conn_args["row_factory"] = self._get_cursor(raw_cursor) # Use Any type for the connection args to avoid type conflicts connection = pgConnection.connect(**cast("Any", conn_args)) self.conn = cast("CompatConnection", connection) # Register JSON handlers for both json and jsonb types # This ensures JSON data is properly decoded from bytes to Python objects register_default_adapters(connection) # Add the notice handler AFTER the connection is established if self.enable_log_db_messages and hasattr(self.conn, "add_notice_handler"): self.conn.add_notice_handler(self._notice_handler) else: # psycopg2 raw_cursor = conn.extra_dejson.get("cursor", False) if raw_cursor: conn_args["cursor_factory"] = self._get_cursor(raw_cursor) self.conn = cast("CompatConnection", psycopg2.connect(**conn_args)) return self.conn
@overload
[docs] def get_df( self, sql: str | list[str], parameters: list | tuple | Mapping[str, Any] | None = None, *, df_type: Literal["pandas"] = "pandas", **kwargs: Any, ) -> PandasDataFrame: ...
@overload def get_df( self, sql: str | list[str], parameters: list | tuple | Mapping[str, Any] | None = None, *, df_type: Literal["polars"] = ..., **kwargs: Any, ) -> PolarsDataFrame: ... def get_df( self, sql: str | list[str], parameters: list | tuple | Mapping[str, Any] | None = None, *, df_type: Literal["pandas", "polars"] = "pandas", **kwargs: Any, ) -> PandasDataFrame | PolarsDataFrame: """ Execute the sql and returns a dataframe. :param sql: the sql statement to be executed (str) or a list of sql statements to execute :param parameters: The parameters to render the SQL query with. :param df_type: Type of dataframe to return, either "pandas" or "polars" :param kwargs: (optional) passed into `pandas.io.sql.read_sql` or `polars.read_database` method :return: A pandas or polars DataFrame containing the query results. """ if df_type == "pandas": try: from pandas.io import sql as psql except ImportError: raise AirflowOptionalProviderFeatureException( "pandas library not installed, run: pip install " "'apache-airflow-providers-common-sql[pandas]'." ) engine = self.get_sqlalchemy_engine() with engine.connect() as conn: if isinstance(sql, list): sql = "; ".join(sql) # Or handle multiple queries differently return cast("PandasDataFrame", psql.read_sql(sql, con=conn, params=parameters, **kwargs)) elif df_type == "polars": return self._get_polars_df(sql, parameters, **kwargs) else: raise ValueError(f"Unsupported df_type: {df_type}")
[docs] def copy_expert(self, sql: str, filename: str) -> None: """ Execute SQL using psycopg's ``copy_expert`` method. Necessary to execute COPY command without access to a superuser. Note: if this method is called with a "COPY FROM" statement and the specified input file does not exist, it creates an empty file and no data is loaded, but the operation succeeds. So if users want to be aware when the input file does not exist, they have to check its existence by themselves. """ self.log.info("Running copy expert: %s, filename: %s", sql, filename) if USE_PSYCOPG3: if " from stdin" in sql.lower(): # Handle COPY FROM STDIN: read from the file and write to the database. if not os.path.isfile(filename): with open(filename, "w"): pass # Create an empty file to prevent errors. with open(filename, "rb") as file, self.get_conn() as conn, conn.cursor() as cur: with cur.copy(sql) as copy: while data := file.read(8192): copy.write(data) conn.commit() else: # Handle COPY TO STDOUT: read from the database and write to the file. with open(filename, "wb") as file, self.get_conn() as conn, conn.cursor() as cur: with cur.copy(sql) as copy: for data in copy: file.write(data) conn.commit() else: if not os.path.isfile(filename): with open(filename, "w"): pass with ( open(filename, "r+") as file, closing(self.get_conn()) as conn, closing(conn.cursor()) as cur, ): cur.copy_expert(sql, file) file.truncate(file.tell()) conn.commit()
[docs] def get_uri(self) -> str: """ Extract the URI from the connection. :return: the extracted URI in Sqlalchemy URI format. """ return self.sqlalchemy_url.render_as_string(hide_password=False)
[docs] def bulk_load(self, table: str, tmp_file: str) -> None: """Load a tab-delimited file into a database table.""" self.copy_expert(f"COPY {table} FROM STDIN", tmp_file)
[docs] def bulk_dump(self, table: str, tmp_file: str) -> None: """Dump a database table into a tab-delimited file.""" self.copy_expert(f"COPY {table} TO STDOUT", tmp_file)
@staticmethod def _serialize_cell_ppg2(cell: object, conn: CompatConnection | None = None) -> Any: """ Serialize a cell using psycopg2. Psycopg2 adapts all arguments to the ``execute()`` method internally, hence we return the cell without any conversion. See https://www.psycopg.org/docs/extensions.html#sql-adaptation-protocol-objects for more information. To perform custom type adaptation please use register_adapter function https://www.psycopg.org/docs/extensions.html#psycopg2.extensions.register_adapter. :param cell: The cell to insert into the table :param conn: The database connection :return: The cell """ return cell @staticmethod def _serialize_cell_ppg3(cell: object, conn: CompatConnection | None = None) -> Any: """Serialize a cell using psycopg3.""" if isinstance(cell, (dict, list)): try: from psycopg.types.json import Json return Json(cell) except ImportError: return cell return cell @staticmethod def _serialize_cell(cell: object, conn: Any | None = None) -> Any: if USE_PSYCOPG3: return PostgresHook._serialize_cell_ppg3(cell, conn) return PostgresHook._serialize_cell_ppg2(cell, conn)
[docs] def get_iam_token(self, conn: Connection) -> tuple[str, str, int]: """ Get the IAM token. This uses AWSHook to retrieve a temporary password to connect to Postgres or Redshift. Port is required. If none is provided, the default 5432 is used. """ try: from airflow.providers.amazon.aws.hooks.base_aws import AwsBaseHook except ImportError: from airflow.exceptions import AirflowOptionalProviderFeatureException raise AirflowOptionalProviderFeatureException( "apache-airflow-providers-amazon not installed, run: " "pip install 'apache-airflow-providers-postgres[amazon]'." ) aws_conn_id = conn.extra_dejson.get("aws_conn_id", "aws_default") login = conn.login if conn.extra_dejson.get("redshift", False): port = conn.port or 5439 # Pull the custer-identifier from the beginning of the Redshift URL # ex. my-cluster.ccdre4hpd39h.us-east-1.redshift.amazonaws.com returns my-cluster cluster_identifier = conn.extra_dejson.get( "cluster-identifier", cast("str", conn.host).split(".")[0] ) redshift_client = AwsBaseHook(aws_conn_id=aws_conn_id, client_type="redshift").conn # https://boto3.amazonaws.com/v1/documentation/api/latest/reference/services/redshift/client/get_cluster_credentials.html#Redshift.Client.get_cluster_credentials cluster_creds = redshift_client.get_cluster_credentials( DbUser=login, DbName=self.database or conn.schema, ClusterIdentifier=cluster_identifier, AutoCreate=False, ) token = cluster_creds["DbPassword"] login = cluster_creds["DbUser"] elif conn.extra_dejson.get("redshift-serverless", False): port = conn.port or 5439 # Pull the workgroup-name from the query params/extras, if not there then pull it from the # beginning of the Redshift URL # ex. workgroup-name.ccdre4hpd39h.us-east-1.redshift.amazonaws.com returns workgroup-name workgroup_name = conn.extra_dejson.get("workgroup-name", cast("str", conn.host).split(".")[0]) redshift_serverless_client = AwsBaseHook( aws_conn_id=aws_conn_id, client_type="redshift-serverless" ).conn # https://boto3.amazonaws.com/v1/documentation/api/latest/reference/services/redshift-serverless/client/get_credentials.html#RedshiftServerless.Client.get_credentials cluster_creds = redshift_serverless_client.get_credentials( dbName=self.database or conn.schema, workgroupName=workgroup_name, ) token = cluster_creds["dbPassword"] login = cluster_creds["dbUser"] else: port = conn.port or 5432 rds_client = AwsBaseHook(aws_conn_id=aws_conn_id, client_type="rds").conn # https://boto3.amazonaws.com/v1/documentation/api/latest/reference/services/rds/client/generate_db_auth_token.html#RDS.Client.generate_db_auth_token token = rds_client.generate_db_auth_token(conn.host, port, conn.login) return cast("str", login), cast("str", token), port
[docs] def get_table_primary_key(self, table: str, schema: str | None = "public") -> list[str] | None: """ Get the table's primary key. :param table: Name of the target table :param schema: Name of the target schema, public by default :return: Primary key columns list """ return self.dialect.get_primary_keys(table=table, schema=schema)
[docs] def get_openlineage_database_info(self, connection) -> DatabaseInfo: """Return Postgres/Redshift specific information for OpenLineage.""" from airflow.providers.openlineage.sqlparser import DatabaseInfo is_redshift = connection.extra_dejson.get("redshift", False) if is_redshift: authority = self._get_openlineage_redshift_authority_part(connection) else: authority = DbApiHook.get_openlineage_authority_part(connection, default_port=5432) return DatabaseInfo( scheme="postgres" if not is_redshift else "redshift", authority=authority, database=self.database or connection.schema, )
def _get_openlineage_redshift_authority_part(self, connection) -> str: try: from airflow.providers.amazon.aws.hooks.base_aws import AwsBaseHook except ImportError: from airflow.exceptions import AirflowOptionalProviderFeatureException raise AirflowOptionalProviderFeatureException( "apache-airflow-providers-amazon not installed, run: " "pip install 'apache-airflow-providers-postgres[amazon]'." ) aws_conn_id = connection.extra_dejson.get("aws_conn_id", "aws_default") port = connection.port or 5439 cluster_identifier = connection.extra_dejson.get("cluster-identifier", connection.host.split(".")[0]) region_name = AwsBaseHook(aws_conn_id=aws_conn_id).region_name return f"{cluster_identifier}.{region_name}:{port}"
[docs] def get_openlineage_database_dialect(self, connection) -> str: """Return postgres/redshift dialect.""" return "redshift" if connection.extra_dejson.get("redshift", False) else "postgres"
[docs] def get_openlineage_default_schema(self) -> str | None: """Return current schema. This is usually changed with ``SEARCH_PATH`` parameter.""" return self.get_first("SELECT CURRENT_SCHEMA;")[0]
@classmethod
[docs] def get_ui_field_behaviour(cls) -> dict[str, Any]: return { "hidden_fields": [], "relabeling": { "schema": "Database", }, }
[docs] def get_db_log_messages(self, conn) -> None: """Log database messages.""" if not self.enable_log_db_messages: return if USE_PSYCOPG3: self.log.debug( "With psycopg3, database notices are logged upon creation (via self._notice_handler)." ) return for output in conn.notices: self.log.info(output)
[docs] def insert_rows( self, table, rows, target_fields=None, commit_every=1000, replace=False, *, executemany=False, fast_executemany=False, autocommit=False, **kwargs, ): """ Insert a collection of tuples into a table. Rows are inserted in chunks, each chunk (of size ``commit_every``) is done in a new transaction. :param table: Name of the target table :param rows: The rows to insert into the table :param target_fields: The names of the columns to fill in the table :param commit_every: The maximum number of rows to insert in one transaction. Set to 0 to insert all rows in one transaction. :param replace: Whether to replace instead of insert :param executemany: If True, all rows are inserted at once in chunks defined by the commit_every parameter. This only works if all rows have same number of column names, but leads to better performance. :param fast_executemany: If True, rows will be inserted using an optimized bulk execution strategy (``psycopg2.extras.execute_batch``). This can significantly improve performance for large inserts. If set to False, the method falls back to the default implementation from ``DbApiHook.insert_rows``. :param autocommit: What to set the connection's autocommit setting to before executing the query. """ # if fast_executemany is disabled, defer to default implementation of insert_rows in DbApiHook if not fast_executemany: return super().insert_rows( table, rows, target_fields=target_fields, commit_every=commit_every, replace=replace, executemany=executemany, autocommit=autocommit, **kwargs, ) # if fast_executemany is enabled, use optimized execute_batch from psycopg nb_rows = 0 with self._create_autocommit_connection(autocommit) as conn: conn.commit() with closing(conn.cursor()) as cur: for chunked_rows in chunked(rows, commit_every): values = list( map( lambda row: self._serialize_cells(row, conn), chunked_rows, ) ) sql = self._generate_insert_sql(table, values[0], target_fields, replace, **kwargs) self.log.debug("Generated sql: %s", sql) try: execute_batch(cur, sql, values, page_size=commit_every) except Exception as e: self.log.error("Generated sql: %s", sql) self.log.error("Parameters: %s", values) raise e conn.commit() nb_rows += len(chunked_rows) self.log.info("Loaded %s rows into %s so far", nb_rows, table) self.log.info("Done loading. Loaded a total of %s rows into %s", nb_rows, table)

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