Support direct TLS connections (i.e. no STARTTLS) (#923)

Adding direct_tls param that when equal to True alongside the ssl param being set to a ssl.SSLContext will result in a direct SSL connection being made, skipping STARTTLS implementation. Closes #906

Author: jackwotherspoon

asyncpg/connect_utils.py

@@ -53,6 +53,7 @@ def parse(cls, sslmode):
  'database',
  'ssl',
  'sslmode',
+ 'direct_tls',
  'connect_timeout',
  'server_settings',
  ])
@@ -258,7 +259,7 @@ def _dot_postgresql_path(filename) -> pathlib.Path:
 
 def _parse_connect_dsn_and_args(*, dsn, host, port, user,
  password, passfile, database, ssl,
- connect_timeout, server_settings):
+ direct_tls, connect_timeout, server_settings):
  # `auth_hosts` is the version of host information for the purposes
  # of reading the pgpass file.
  auth_hosts = None
@@ -601,8 +602,8 @@ def _parse_connect_dsn_and_args(*, dsn, host, port, user,
 
  params = _ConnectionParameters(
  user=user, password=password, database=database, ssl=ssl,
- sslmode=sslmode, connect_timeout=connect_timeout,
- server_settings=server_settings)
+ sslmode=sslmode, direct_tls=direct_tls,
+ connect_timeout=connect_timeout, server_settings=server_settings)
 
  return addrs, params
 
@@ -612,7 +613,7 @@ def _parse_connect_arguments(*, dsn, host, port, user, password, passfile,
  statement_cache_size,
  max_cached_statement_lifetime,
  max_cacheable_statement_size,
- ssl, server_settings):
+ ssl, direct_tls, server_settings):
 
  local_vars = locals()
  for var_name in {'max_cacheable_statement_size',
@@ -640,8 +641,8 @@ def _parse_connect_arguments(*, dsn, host, port, user, password, passfile,
  addrs, params = _parse_connect_dsn_and_args(
  dsn=dsn, host=host, port=port, user=user,
  password=password, passfile=passfile, ssl=ssl,
- database=database, connect_timeout=timeout,
- server_settings=server_settings)
+ direct_tls=direct_tls, database=database,
+ connect_timeout=timeout, server_settings=server_settings)
 
  config = _ClientConfiguration(
  command_timeout=command_timeout,
@@ -812,6 +813,14 @@ async def __connect_addr(
  if isinstance(addr, str):
  # UNIX socket
  connector = loop.create_unix_connection(proto_factory, addr)
+
+ elif params.ssl and params.direct_tls:
+ # if ssl and direct_tls are given, skip STARTTLS and perform direct
+ # SSL connection
+ connector = loop.create_connection(
+ proto_factory, *addr, ssl=params.ssl
+ )
+
  elif params.ssl:
  connector = _create_ssl_connection(
  proto_factory, *addr, loop=loop, ssl_context=params.ssl,

asyncpg/connection.py

@@ -1789,6 +1789,7 @@ async def connect(dsn=None, *,
  max_cacheable_statement_size=1024 * 15,
  command_timeout=None,
  ssl=None,
+ direct_tls=False,
  connection_class=Connection,
  record_class=protocol.Record,
  server_settings=None):
@@ -1984,6 +1985,10 @@ async def connect(dsn=None, *,
  ... await con.close()
  >>> asyncio.run(run())
 
+ :param bool direct_tls:
+ Pass ``True`` to skip PostgreSQL STARTTLS mode and perform a direct
+ SSL connection. Must be used alongside ``ssl`` param.
+
  :param dict server_settings:
  An optional dict of server runtime parameters. Refer to
  PostgreSQL documentation for
@@ -2094,6 +2099,7 @@ async def connect(dsn=None, *,
  password=password,
  passfile=passfile,
  ssl=ssl,
+ direct_tls=direct_tls,
  database=database,
  server_settings=server_settings,
  command_timeout=command_timeout,

tests/test_connect.py

@@ -811,7 +811,8 @@ def run_testcase(self, testcase):
  addrs, params = connect_utils._parse_connect_dsn_and_args(
  dsn=dsn, host=host, port=port, user=user, password=password,
  passfile=passfile, database=database, ssl=sslmode,
- connect_timeout=None, server_settings=server_settings)
+ direct_tls=False, connect_timeout=None,
+ server_settings=server_settings)
 
  params = {
  k: v for k, v in params._asdict().items()
@@ -829,6 +830,10 @@ def run_testcase(self, testcase):
  # unless explicitly tested for.
  params.pop('ssl', None)
  params.pop('sslmode', None)
+ if 'direct_tls' not in expected[1]:
+ # Avoid the hassle of specifying direct_tls
+ # unless explicitly tested for
+ params.pop('direct_tls', False)
 
  self.assertEqual(expected, result, 'Testcase: {}'.format(testcase))