Queue federation: improve logging

around federated queue link state transitions (pause/unpause).

References #8297.

Author: michaelklishin

deps/rabbitmq_federation/src/rabbit_federation_link_util.erl

@@ -140,9 +140,13 @@ connection_error(remote_start, {{shutdown, {server_initiated_close, Code, Messag
 connection_error(remote_start, E, Upstream, UParams, XorQName, State) ->
     rabbit_federation_status:report(
       Upstream, UParams, XorQName, clean_reason(E)),
+    Reason = case E of
+        {error, Value} -> Value;
+        Other -> Other
+    end,
     log_warning(XorQName, "did not connect to ~ts. Reason: ~tp",
                 [rabbit_federation_upstream:params_to_string(UParams),
-                 E]),
+                 Reason]),
     {stop, {shutdown, restart}, State};
 
 connection_error(remote, E, Upstream, UParams, XorQName, State) ->

deps/rabbitmq_federation/src/rabbit_federation_queue_link.erl

@@ -104,7 +104,11 @@ handle_cast(pause, State = #state{run = false}) ->
 handle_cast(pause, State = #not_started{}) ->
     {noreply, State#not_started{run = false}};
 
-handle_cast(pause, State = #state{ch = Ch, upstream = Upstream}) ->
+handle_cast(pause, State = #state{ch = Ch, upstream = Upstream = #upstream{
+        name = UpName, queue_name = QName
+    }}) ->
+    rabbit_log_federation:debug("Federation link of ~s (upstream: '~s'): asked to pause",
+                                [QName, UpName]),
     cancel(Ch, Upstream),
     {noreply, State#state{run = false}};
 
@@ -305,18 +309,22 @@ visit_match(_ ,_) ->
 consumer_tag(#upstream{consumer_tag = ConsumerTag}) ->
     ConsumerTag.
 
-consume(Ch, Upstream, UQueue) ->
+consume(Ch, Upstream = #upstream{name = UpName}, UQueue) ->
     ConsumerTag = consumer_tag(Upstream),
     NoAck = Upstream#upstream.ack_mode =:= 'no-ack',
+    rabbit_log_federation:debug("Federation link of ~ts: will consume from the upstream '~ts'",
+                                [rabbit_misc:rs(amqqueue:get_name(UQueue)), UpName]),
     amqp_channel:cast(
       Ch, #'basic.consume'{queue        = name(UQueue),
                            no_ack       = NoAck,
                            nowait       = true,
                            consumer_tag = ConsumerTag,
                            arguments    = [{<<"x-priority">>, long, -1}]}).
 
-cancel(Ch, Upstream) ->
+cancel(Ch, Upstream = #upstream{name = UpName, queue_name = QName}) ->
     ConsumerTag = consumer_tag(Upstream),
+    rabbit_log_federation:debug("Federation queue '~ts' link: will cancel consumer '~ts' on upstream '~ts'",
+                                [QName, ConsumerTag, UpName]),
     amqp_channel:cast(Ch, #'basic.cancel'{nowait       = true,
                                           consumer_tag = ConsumerTag}).
 

deps/rabbitmq_federation/src/rabbit_federation_upstream.erl

@@ -61,7 +61,7 @@ params_table(SafeURI, XorQ) ->
 
 params_to_string(#upstream_params{safe_uri = SafeURI,
                                   x_or_q   = XorQ}) ->
-    print("~ts on ~ts", [rabbit_misc:rs(r(XorQ)), SafeURI]).
+    print("~ts on '~ts'", [rabbit_misc:rs(r(XorQ)), SafeURI]).
 
 remove_credentials(URI) ->
     list_to_binary(amqp_uri:remove_credentials(binary_to_list(URI))).