Files
Nominatim/src/nominatim_db/db/utils.py
2024-07-29 08:50:19 +02:00

74 lines
2.4 KiB
Python

# SPDX-License-Identifier: GPL-3.0-or-later
#
# This file is part of Nominatim. (https://nominatim.org)
#
# Copyright (C) 2024 by the Nominatim developer community.
# For a full list of authors see the git log.
"""
Helper functions for handling DB accesses.
"""
from typing import IO, Optional, Union
import subprocess
import logging
import gzip
from pathlib import Path
from .connection import get_pg_env
from ..errors import UsageError
LOG = logging.getLogger()
def _pipe_to_proc(proc: 'subprocess.Popen[bytes]',
fdesc: Union[IO[bytes], gzip.GzipFile]) -> int:
assert proc.stdin is not None
chunk = fdesc.read(2048)
while chunk and proc.poll() is None:
try:
proc.stdin.write(chunk)
except BrokenPipeError as exc:
raise UsageError("Failed to execute SQL file.") from exc
chunk = fdesc.read(2048)
return len(chunk)
def execute_file(dsn: str, fname: Path,
ignore_errors: bool = False,
pre_code: Optional[str] = None,
post_code: Optional[str] = None) -> None:
""" Read an SQL file and run its contents against the given database
using psql. Use `pre_code` and `post_code` to run extra commands
before or after executing the file. The commands are run within the
same session, so they may be used to wrap the file execution in a
transaction.
"""
cmd = ['psql']
if not ignore_errors:
cmd.extend(('-v', 'ON_ERROR_STOP=1'))
if not LOG.isEnabledFor(logging.INFO):
cmd.append('--quiet')
with subprocess.Popen(cmd, env=get_pg_env(dsn), stdin=subprocess.PIPE) as proc:
assert proc.stdin is not None
try:
if not LOG.isEnabledFor(logging.INFO):
proc.stdin.write('set client_min_messages to WARNING;'.encode('utf-8'))
if pre_code:
proc.stdin.write((pre_code + ';').encode('utf-8'))
if fname.suffix == '.gz':
with gzip.open(str(fname), 'rb') as fdesc:
remain = _pipe_to_proc(proc, fdesc)
else:
with fname.open('rb') as fdesc:
remain = _pipe_to_proc(proc, fdesc)
if remain == 0 and post_code:
proc.stdin.write((';' + post_code).encode('utf-8'))
finally:
proc.stdin.close()
ret = proc.wait()
if ret != 0 or remain > 0:
raise UsageError("Failed to execute SQL file.")