170 lines
5 KiB
Python
170 lines
5 KiB
Python
""" PostgreSQL client """
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import datetime
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import logging
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import sys
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import psycopg2
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from psycopg2.extras import RealDictCursor
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from mylib.db import DB, DBFailToConnect
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log = logging.getLogger(__name__)
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class PgDB(DB):
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"""PostgreSQL client"""
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_host = None
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_user = None
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_pwd = None
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_db = None
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date_format = "%Y-%m-%d"
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datetime_format = "%Y-%m-%d %H:%M:%S"
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def __init__(self, host, user, pwd, db, **kwargs):
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self._host = host
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self._user = user
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self._pwd = pwd
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self._db = db
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super().__init__(**kwargs)
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def connect(self, exit_on_error=True):
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"""Connect to PostgreSQL server"""
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if self._conn is None:
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try:
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log.info(
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"Connect on PostgreSQL server %s as %s on database %s",
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self._host,
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self._user,
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self._db,
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)
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self._conn = psycopg2.connect(
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dbname=self._db, user=self._user, host=self._host, password=self._pwd
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)
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except psycopg2.Error as err:
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log.fatal(
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"An error occurred during Postgresql database connection (%s@%s, database=%s).",
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self._user,
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self._host,
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self._db,
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exc_info=1,
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)
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if exit_on_error:
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sys.exit(1)
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else:
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raise DBFailToConnect(f"{self._user}@{self._host}:{self._db}") from err
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return True
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def close(self):
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"""Close connection with PostgreSQL server (if opened)"""
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if self._conn:
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self._conn.close()
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self._conn = None
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def setEncoding(self, enc):
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"""Set connection encoding"""
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if self._conn:
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try:
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self._conn.set_client_encoding(enc)
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return True
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except psycopg2.Error:
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log.error(
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'An error occurred setting Postgresql database connection encoding to "%s"',
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enc,
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exc_info=1,
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)
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return False
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def doSQL(self, sql, params=None):
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"""
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Run SQL query and commit changes (rollback on error)
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:param sql: The SQL query
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:param params: The SQL query's parameters as dict (optional)
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:return: True on success, False otherwise
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:rtype: bool
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"""
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if self.just_try:
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log.debug("Just-try mode : do not really execute SQL query '%s'", sql)
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return True
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cursor = self._conn.cursor()
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try:
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self._log_query(sql, params)
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if params is None:
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cursor.execute(sql)
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else:
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cursor.execute(sql, params)
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self._conn.commit()
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return True
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except psycopg2.Error:
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self._log_query_exception(sql, params)
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self._conn.rollback()
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return False
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def doSelect(self, sql, params=None):
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"""
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Run SELECT SQL query and return list of selected rows as dict
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:param sql: The SQL query
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:param params: The SQL query's parameters as dict (optional)
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:return: List of selected rows as dict on success, False otherwise
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:rtype: list, bool
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"""
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cursor = self._conn.cursor(cursor_factory=RealDictCursor)
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try:
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self._log_query(sql, params)
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cursor.execute(sql, params)
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results = cursor.fetchall()
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return list(map(dict, results))
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except psycopg2.Error:
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self._log_query_exception(sql, params)
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return False
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#
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# Deprecated helpers
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#
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@classmethod
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def _quote_value(cls, value):
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"""Quote a value for SQL query"""
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if value is None:
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return "NULL"
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if isinstance(value, (int, float)):
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return str(value)
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if isinstance(value, datetime.datetime):
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value = cls._format_datetime(value)
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elif isinstance(value, datetime.date):
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value = cls._format_date(value)
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# pylint: disable=consider-using-f-string
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return "'{}'".format(value.replace("'", "''"))
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@classmethod
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def _format_datetime(cls, value):
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"""Format datetime object as string"""
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assert isinstance(value, datetime.datetime)
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return value.strftime(cls.datetime_format)
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@classmethod
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def _format_date(cls, value):
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"""Format date object as string"""
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assert isinstance(value, (datetime.date, datetime.datetime))
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return value.strftime(cls.date_format)
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@classmethod
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def time2datetime(cls, time):
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"""Convert timestamp to datetime string"""
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return cls._format_datetime(datetime.datetime.fromtimestamp(int(time)))
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@classmethod
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def time2date(cls, time):
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"""Convert timestamp to date string"""
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return cls._format_date(datetime.date.fromtimestamp(int(time)))
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