AWS peer discovery: ensure consistent hostname path ordering (address feedback on debug logs and sorting helper functions)

Author: BenAtAmazon

deps/rabbitmq_peer_discovery_aws/src/rabbit_peer_discovery_aws.erl

@@ -372,40 +372,18 @@ get_value(_, []) ->
 get_value(Key, Props) when is_integer(Key) ->
     {"item", Props2} = lists:nth(Key, Props),
     Props2;
-get_value("networkInterfaceSet", Props) ->
-    NetworkInterfaces = proplists:get_value("networkInterfaceSet", Props),
-    sort_network_interfaces_by_device_index(NetworkInterfaces);
-get_value("privateIpAddressesSet", Props) ->
-    PrivateIpAddresses = proplists:get_value("privateIpAddressesSet", Props),
-    sort_private_ip_addresses_by_primary(PrivateIpAddresses);
 get_value(Key, Props) ->
-    proplists:get_value(Key, Props).
-
-%% Sort network interfaces by deviceIndex to ensure consistent ENI ordering
--spec sort_network_interfaces_by_device_index(list()) -> list().
-sort_network_interfaces_by_device_index(NetworkInterfaces) when is_list(NetworkInterfaces) ->
-    BeforeInfo = [format_network_interface_info(Props) || {"item", Props} <- NetworkInterfaces],
-    Sorted = lists:sort(fun({"item", A}, {"item", B}) ->
-        device_index(A) =< device_index(B)
-    end, NetworkInterfaces),
-    AfterInfo = [format_network_interface_info(Props) || {"item", Props} <- Sorted],
-    ?LOG_DEBUG("AWS peer discovery sorted network interfaces from ~tp to ~tp", [BeforeInfo, AfterInfo]),
-    Sorted;
-sort_network_interfaces_by_device_index(Other) ->
-    Other.
-
-%% Sort private IP addresses by primary flag to ensure primary=true comes first
--spec sort_private_ip_addresses_by_primary(list()) -> list().
-sort_private_ip_addresses_by_primary(PrivateIpAddresses) when is_list(PrivateIpAddresses) ->
-    BeforeInfo = [format_private_ip_info(Props) || {"item", Props} <- PrivateIpAddresses],
-    Sorted = lists:sort(fun({"item", A}, {"item", B}) ->
-        is_primary(A) >= is_primary(B)
-    end, PrivateIpAddresses),
-    AfterInfo = [format_private_ip_info(Props) || {"item", Props} <- Sorted],
-    ?LOG_DEBUG("AWS peer discovery sorted private IPs from ~tp to ~tp", [BeforeInfo, AfterInfo]),
-    Sorted;
-sort_private_ip_addresses_by_primary(Other) ->
-    Other.
+    Value = proplists:get_value(Key, Props),
+    sort_ec2_hostname_path_set_members(Key, Value).
+
+%% Sort AWS API responses for consistent ordering
+-spec sort_ec2_hostname_path_set_members(string(), any()) -> any().
+sort_ec2_hostname_path_set_members("networkInterfaceSet", NetworkInterfaces) when is_list(NetworkInterfaces) ->
+    lists:sort(fun({"item", A}, {"item", B}) -> device_index(A) =< device_index(B) end, NetworkInterfaces);
+sort_ec2_hostname_path_set_members("privateIpAddressesSet", PrivateIpAddresses) when is_list(PrivateIpAddresses) ->
+    lists:sort(fun({"item", A}, {"item", B}) -> is_primary(A) >= is_primary(B) end, PrivateIpAddresses);
+sort_ec2_hostname_path_set_members(_, Value) ->
+    Value.
 
 %% Extract deviceIndex from network interface attachment
 -spec device_index(props()) -> integer().
@@ -427,23 +405,6 @@ is_primary(IpAddress) ->
         _ -> false
     end.
 
-%% Format network interface info for logging
--spec format_network_interface_info(props()) -> string().
-format_network_interface_info(Interface) ->
-    ENI = proplists:get_value("networkInterfaceId", Interface, "unknown"),
-    DeviceIndex = device_index(Interface),
-    lists:flatten(io_lib:format("~s:~w", [ENI, DeviceIndex])).
-
-%% Format private IP info for logging  
--spec format_private_ip_info(props()) -> string().
-format_private_ip_info(IpAddress) ->
-    IP = proplists:get_value("privateIpAddress", IpAddress, "unknown"),
-    Primary = case is_primary(IpAddress) of
-        true -> "primary";
-        false -> "secondary"
-    end,
-    lists:flatten(io_lib:format("~s:~s", [IP, Primary])).
-
 -spec get_tags() -> tags().
 get_tags() ->
     Tags = get_config_key(aws_ec2_tags, ?CONFIG_MODULE:config_map(?BACKEND_CONFIG_KEY)),

deps/rabbitmq_peer_discovery_aws/test/unit_SUITE.erl

@@ -110,7 +110,7 @@ network_interface_sorting(_Config) ->
     ],
 
     %% Should sort ENIs by deviceIndex
-    Sorted = rabbit_peer_discovery_aws:sort_network_interfaces_by_device_index(NetworkInterfaces),
+    Sorted = rabbit_peer_discovery_aws:sort_ec2_hostname_path_set_members("networkInterfaceSet", NetworkInterfaces),
 
     %% Should have all 3 ENIs
     ?assertEqual(3, length(Sorted)),
@@ -147,7 +147,7 @@ private_ip_address_sorting(_Config) ->
         ]}
     ],
 
-    Sorted = rabbit_peer_discovery_aws:sort_private_ip_addresses_by_primary(PrivateIpAddresses),
+    Sorted = rabbit_peer_discovery_aws:sort_ec2_hostname_path_set_members("privateIpAddressesSet", PrivateIpAddresses),
     ?assertEqual(3, length(Sorted)),
 
     %% Primary IP (primary=true) should be first