RMQ-1263: Shovels Management: show metrics (incl. forwarded counter) in the Shovel Status page

(cherry picked from commit f90dab71f147548c5e9ad921a0bc618179bd34c2)

Conflicts:
	deps/rabbitmq_shovel_management/src/rabbit_shovel_mgmt_util.erl

deps/rabbitmq_shovel_management/priv/www/js/tmpl/shovels.ejs

@@ -17,6 +17,10 @@
     <th>Virtual Host</th>
 <% } %>
     <th>State</th>
+    <th>Remaining</th>
+    <th>Remaining Unacked</th>
+    <th>Pending</th>
+    <th>Forwarded</th>
     <th colspan="3">Source</th>
     <th colspan="3">Destination</th>
     <th>Last changed</th>
@@ -47,6 +51,10 @@
     <td><%= shovel.timestamp %></td>
 <% } else { %>
       <td><%= fmt_object_state(shovel) %></td>
+      <td><%= fmt_string(shovel.remaining) %></td>
+      <td><%= fmt_string(shovel.remaining_unacked) %></td>
+      <td><%= fmt_string(shovel.pending) %></td>
+      <td><%= fmt_string(shovel.forwarded) %></td>
       <td><%= fmt_string(shovel.src_protocol) %></td>
       <td><%= shovel.src_uri == undefined ? fmt_string(shovel.src_uri) : fmt_string(fmt_uri_with_credentials(shovel.src_uri)) %></td>
       <td><%= fmt_shovel_endpoint('src_', shovel) %></td>

deps/rabbitmq_shovel_management/src/rabbit_shovel_mgmt_util.erl

@@ -42,9 +42,10 @@ status(Node) ->
             [format(Node, I) || I <- Status]
     end.
 
-format(Node, {Name, Type, Info, _Metrics, TS}) ->
+format(Node, {Name, Type, Info, Metrics, TS}) ->
     [{node, Node}, {timestamp, format_ts(TS)}] ++
         format_name(Type, Name) ++
+        format_metrics(Metrics) ++
         format_info(Info);
 format(Node, {Name, Type, Info, TS}) ->
     [{node, Node}, {timestamp, format_ts(TS)}] ++
@@ -57,6 +58,11 @@ format_name(dynamic, {VHost, Name}) -> [{name,  Name},
     {vhost, VHost},
     {type,  dynamic}].
 
+format_metrics(undefined) ->
+    [];
+format_metrics(Metrics) when is_map(Metrics) ->
+    maps:to_list(Metrics).
+
 format_info(starting) ->
     [{state, starting}];