type annotations for DB utils

[nominatim.git] / nominatim / db / utils.py

diff --git a/nominatim/db/utils.py b/nominatim/db/utils.py
index b376940d804af364c049864a07649c897b515f0f..e2b63e1dd0e360e528724e5019608a7153e31b5f 100644 (file)
--- a/nominatim/db/utils.py
+++ b/nominatim/db/utils.py
@@ -1,16 +1,27 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# This file is part of Nominatim. (https://nominatim.org)
+#
+# Copyright (C) 2022 by the Nominatim developer community.
+# For a full list of authors see the git log.

 """
 Helper functions for handling DB accesses.
 """
 """
 Helper functions for handling DB accesses.
 """

+from typing import IO, Optional, Union

 import subprocess
 import logging
 import gzip
 import subprocess
 import logging
 import gzip

+import io
+from pathlib import Path

 
 from nominatim.db.connection import get_pg_env
 from nominatim.errors import UsageError
 
 LOG = logging.getLogger()
 
 
 from nominatim.db.connection import get_pg_env
 from nominatim.errors import UsageError
 
 LOG = logging.getLogger()
 

-def _pipe_to_proc(proc, fdesc):
+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:
     chunk = fdesc.read(2048)
     while chunk and proc.poll() is None:
         try:


@@ -21,7 +32,10 @@ def _pipe_to_proc(proc, fdesc):
 
     return len(chunk)
 
 
     return len(chunk)
 

-def execute_file(dsn, fname, ignore_errors=False, pre_code=None, post_code=None):
+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
     """ 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


@@ -33,27 +47,75 @@ def execute_file(dsn, fname, ignore_errors=False, pre_code=None, post_code=None)
         cmd.extend(('-v', 'ON_ERROR_STOP=1'))
     if not LOG.isEnabledFor(logging.INFO):
         cmd.append('--quiet')
         cmd.extend(('-v', 'ON_ERROR_STOP=1'))
     if not LOG.isEnabledFor(logging.INFO):
         cmd.append('--quiet')

-    proc = subprocess.Popen(cmd, env=get_pg_env(dsn), stdin=subprocess.PIPE)

 
 

-    try:
-        if not LOG.isEnabledFor(logging.INFO):
-            proc.stdin.write('set client_min_messages to WARNING;'.encode('utf-8'))
+    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 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 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 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.")
 
     if ret != 0 or remain > 0:
         raise UsageError("Failed to execute SQL file.")

+
+
+# List of characters that need to be quoted for the copy command.
+_SQL_TRANSLATION = {ord('\\'): '\\\\',
+                    ord('\t'): '\\t',
+                    ord('\n'): '\\n'}
+
+
+class CopyBuffer:
+    """ Data collector for the copy_from command.
+    """
+
+    def __init__(self):
+        self.buffer = io.StringIO()
+
+
+    def __enter__(self):
+        return self
+
+
+    def __exit__(self, exc_type, exc_value, traceback):
+        if self.buffer is not None:
+            self.buffer.close()
+
+
+    def add(self, *data):
+        """ Add another row of data to the copy buffer.
+        """
+        first = True
+        for column in data:
+            if first:
+                first = False
+            else:
+                self.buffer.write('\t')
+            if column is None:
+                self.buffer.write('\\N')
+            else:
+                self.buffer.write(str(column).translate(_SQL_TRANSLATION))
+        self.buffer.write('\n')
+
+
+    def copy_out(self, cur, table, columns=None):
+        """ Copy all collected data into the given table.
+        """
+        if self.buffer.tell() > 0:
+            self.buffer.seek(0)
+            cur.copy_from(self.buffer, table, columns=columns)