Add command-line argument --timeout, to configure network timeout

The default connect timeout is five seconds now. The default read
timeout is "infinite".

CHANGES.txt

@@ -4,7 +4,10 @@ Changes for crash
 
 Unreleased
 ==========
-
+- Added command-line argument ``--timeout``, to configure network timeout
+  values in seconds. The default connect timeout is five seconds now,
+  the default read timeout is the default setting of the ``socket`` module,
+  which is "infinite" by default.
 
 2024/01/12 0.30.2
 =================

crate/crash/command.py

@@ -139,6 +139,9 @@ def _conf_or_default(key, value):
     parser.add_argument('--hosts', type=str, nargs='*',
                         default=_conf_or_default('hosts', ['localhost:4200']),
                         help='connect to HOSTS.', metavar='HOSTS')
+    parser.add_argument('--timeout', type=str, metavar='TIMEOUT',
+                        help='Configure network timeout in "<connect_sec>" or "<connect_sec>,<read_sec>" format. '
+                             'Defaults to "5,-1" where "-1" means infinite timeout.', default="5")
     parser.add_argument(
         '--verify-ssl',
         choices=(True, False),
@@ -618,8 +621,59 @@ def save_and_exit():
     save_and_exit()
 
 
+INFINITE_TIMEOUT = -1
+
+
+def _decode_timeout(value):
+    """
+    Decode single timeout value, respecting the `INFINITE_TIMEOUT` surrogate.
+    """
+    if value in [None, INFINITE_TIMEOUT, str(INFINITE_TIMEOUT)]:
+        return None
+    else:
+        return float(value)
+
+
+def _decode_timeouts(timeout):
+    """
+    Decode connect/read timeout values from tuple or string.
+
+    Variant 1: (connect, read)
+    Variant 2: connect,read
+    """
+
+    if timeout is None:
+        timeouts = (INFINITE_TIMEOUT, INFINITE_TIMEOUT)
+    elif isinstance(timeout, (int, float)):
+        timeouts = (timeout, INFINITE_TIMEOUT)
+    elif isinstance(timeout, str):
+        timeouts = timeout.split(",")
+    elif isinstance(timeout, (list, tuple)):
+        timeouts = timeout
+    else:
+        raise TypeError(f"Decoding timeout values failed. Invalid type: {type(timeout)}")
+
+    if len(timeouts) == 1:
+        connect_timeout, read_timeout = timeouts[0], INFINITE_TIMEOUT
+    elif len(timeouts) == 2:
+        connect_timeout, read_timeout = timeouts[0], timeouts[1]
+    else:
+        raise ValueError(f"Decoding timeout values failed: {timeout}")
+
+    return urllib3.Timeout(connect=_decode_timeout(connect_timeout), read=_decode_timeout(read_timeout))
+
+
 def _create_shell(crate_hosts, error_trace, output_writer, is_tty, args,
                   timeout=None, password=None):
+
+    # Explicit "timeout" function argument takes precedence.
+    if timeout is not None:
+        timeout = _decode_timeouts(timeout)
+
+    # Probe `--timeout`` command line argument second.
+    elif args.timeout is not None:
+        timeout = _decode_timeouts(args.timeout)
+
     return CrateShell(crate_hosts,
                       error_trace=error_trace,
                       output_writer=output_writer,

docs/run.rst

@@ -57,6 +57,17 @@ The ``crash`` executable supports multiple command-line options:
 |                               | command will succeed if at least one         |
 |                               | connection is successful.                    |
 +-------------------------------+----------------------------------------------+
+| ``--timeout <TIMEOUT>``       | Configure (connect, read) network timeout    |
+|                               | values, in seconds.                          |
+|                               |                                              |
+|                               | Use a single value to configure the connect  |
+|                               | timeout, or use a tuple separated by comma   |
+|                               | to configure both connect- and read-timeout. |
+|                               |                                              |
+|                               | The default configuration is "5,infinite",   |
+|                               | configuring a connect timeout of five        |
+|                               | seconds with infinite read timeout.          |
++-------------------------------+----------------------------------------------+
 | ``--history <FILENAME>``      | Use ``<FILENAME>`` as a history file.        |
 |                               |                                              |
 |                               | Defaults to the ``crash_history`` file in    |

tests/test_command.py

@@ -7,6 +7,8 @@
 
 from crate.crash.command import (
     Result,
+    _decode_timeout,
+    _decode_timeouts,
     get_information_schema_query,
     host_and_port,
     stmt_type,
@@ -112,6 +114,24 @@ def test_stmt_type(self):
         self.assertEqual(stmt_type(' SELECT 1 ;'), 'SELECT')
         self.assertEqual(stmt_type('\nSELECT\n1\n;\n'), 'SELECT')
 
+    def test_decode_timeout(self):
+        self.assertEqual(_decode_timeout(None), None)
+        self.assertEqual(_decode_timeout(-1), None)
+        self.assertEqual(_decode_timeout(42.42), 42.42)
+        self.assertEqual(_decode_timeout("42.42"), 42.42)
+
+    def test_decode_timeouts(self):
+        # `_decode_timeouts` returns an urllib3.Timeout instance.
+        self.assertEqual(str(_decode_timeouts(None)), 'Timeout(connect=None, read=None, total=None)')
+        self.assertEqual(str(_decode_timeouts(-1)), 'Timeout(connect=None, read=None, total=None)')
+        self.assertEqual(str(_decode_timeouts("-1")), 'Timeout(connect=None, read=None, total=None)')
+        self.assertEqual(str(_decode_timeouts(42.42)), 'Timeout(connect=42.42, read=None, total=None)')
+        self.assertEqual(str(_decode_timeouts("42.42")), 'Timeout(connect=42.42, read=None, total=None)')
+        self.assertEqual(str(_decode_timeouts((42.42, 84.84))), 'Timeout(connect=42.42, read=84.84, total=None)')
+        self.assertEqual(str(_decode_timeouts('42.42, 84.84')), 'Timeout(connect=42.42, read=84.84, total=None)')
+        self.assertEqual(str(_decode_timeouts((-1, 42.42))), 'Timeout(connect=None, read=42.42, total=None)')
+        self.assertEqual(str(_decode_timeouts("-1, 42.42")), 'Timeout(connect=None, read=42.42, total=None)')
+
 
 class TestGetInformationSchemaQuery(TestCase):