RmqCommunicator: add the server_properties property (#107)

This exposes the server properties as returned by the RMQ server when
connecting to clients of the async and threaded RMQ communicators. This
is useful for, amongst other things, checking the server version to
ensure compatibility.

kiwipy/rmq/communicator.py

@@ -4,7 +4,7 @@
 import copy
 import logging
 import typing
-from typing import Union, Optional
+from typing import Union, Optional, Dict
 
 import shortuuid
 import aio_pika
@@ -345,6 +345,33 @@ async def __aexit__(self, exc_type, exc_val, exc_tb):
     def __str__(self):
         return f'RMQCommunicator({self._connection})'
 
+    @property
+    def server_properties(self) -> Dict:
+        """
+        A dictionary containing server properties as returned by the RMQ server at connection time.
+
+        The details are defined by the RMQ standard and can be found here:
+
+        https://www.rabbitmq.com/amqp-0-9-1-reference.html#connection.start.server-properties
+
+        The protocol states that this dictionary SHOULD contain at least:
+            'host'          - specifying the server host name or address
+            'product'       - giving the name of the server product
+            'version'       - giving the name of the server version
+            'platform'      - giving the name of the operating system
+            'copyright'     - if appropriate, and,
+            'information'   - giving other general information
+
+        .. note:: In testing it seems like 'host' is not always returned.  Host information may be found in
+            'cluster_name' but clients shouldn't rely on this.
+
+        :return: the server properties dictionary
+        """
+        if self._connection is None:
+            return {}
+
+        return self._connection.connection.server_properties
+
     @property
     def loop(self):
         """Get the event loop instance driving this communicator connection."""

kiwipy/rmq/threadcomms.py

@@ -5,7 +5,7 @@
 from concurrent.futures import Future as ThreadFuture
 import functools
 import logging
-from typing import Union
+from typing import Union, Dict
 
 import aio_pika
 import deprecation
@@ -148,6 +148,30 @@ def start(self):
     def stop(self):
         self.close()
 
+    @property
+    def server_properties(self) -> Dict:
+        """
+        A dictionary containing server properties as returned by the RMQ server at connection time.
+
+        The details are defined by the RMQ standard and can be found here:
+
+        https://www.rabbitmq.com/amqp-0-9-1-reference.html#connection.start.server-properties
+
+        The protocol states that this dictionary SHOULD contain at least:
+            'host'          - specifying the server host name or address
+            'product'       - giving the name of the server product
+            'version'       - giving the name of the server version
+            'platform'      - giving the name of the operating system
+            'copyright'     - if appropriate, and,
+            'information'   - giving other general information
+
+        .. note:: In testing it seems like 'host' is not always returned.  Host information may be found in
+            'cluster_name' but clients shouldn't rely on this.
+
+        :return: the server properties dictionary
+        """
+        return self._communicator.server_properties
+
     def __enter__(self):
         return self
 

test/rmq/test_coroutine_communicator.py

@@ -197,3 +197,13 @@ def broadcast_subscriber(_comm, _body, _sender=None, _subject=None, _correlation
 
 
 # endregion
+
+
+@pytest.mark.asyncio
+async def test_server_properties(communicator: kiwipy.rmq.RmqCommunicator):
+    props = communicator.server_properties
+    assert isinstance(props, dict)
+
+    assert props['product'] == b'RabbitMQ'
+    assert 'version' in props
+    assert props['platform'].startswith(b'Erlang')

test/rmq/test_rmq_thread_communicator.py

@@ -262,8 +262,15 @@ def test_jupyter_notebook():
     fixture.diff_color_words = False
     fixture.diff_ignore = ('/metadata/language_info/version',)
 
-    # Express the path in a way that will work no matter where the tests are being ran and convert
-    # to str as py35 doesn't support Paths being passed to open()
     my_dir = pathlib.Path(__file__).parent
     with open(my_dir / pathlib.Path('notebooks/communicator.ipynb')) as handle:
         fixture.check(handle)
+
+
+def test_server_properties(thread_communicator: kiwipy.rmq.RmqThreadCommunicator):
+    props = thread_communicator.server_properties
+    assert isinstance(props, dict)
+
+    assert props['product'] == b'RabbitMQ'
+    assert 'version' in props
+    assert props['platform'].startswith(b'Erlang')