Github user olegz commented on a diff in the pull request:
https://github.com/apache/nifi/pull/338#discussion_r60086063
--- Diff:
nifi-nar-bundles/nifi-framework-bundle/nifi-framework/nifi-framework-cluster/src/main/java/org/apache/nifi/cluster/coordination/http/StandardHttpResponseMerger.java
---
@@ -0,0 +1,164 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.nifi.cluster.coordination.http;
+
+import java.io.IOException;
+import java.net.URI;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Set;
+import java.util.stream.Collectors;
+
+import javax.ws.rs.core.StreamingOutput;
+
+import
org.apache.nifi.cluster.coordination.http.endpoints.BulletinBoardEndpointMerger;
+import
org.apache.nifi.cluster.coordination.http.endpoints.ComponentStateEndpointMerger;
+import
org.apache.nifi.cluster.coordination.http.endpoints.ConnectionStatusEndpiontMerger;
+import
org.apache.nifi.cluster.coordination.http.endpoints.ControllerServiceEndpointMerger;
+import
org.apache.nifi.cluster.coordination.http.endpoints.ControllerServiceReferenceEndpointMerger;
+import
org.apache.nifi.cluster.coordination.http.endpoints.ControllerServicesEndpointMerger;
+import
org.apache.nifi.cluster.coordination.http.endpoints.ControllerStatusEndpointMerger;
+import
org.apache.nifi.cluster.coordination.http.endpoints.CountersEndpointMerger;
+import
org.apache.nifi.cluster.coordination.http.endpoints.DropRequestEndpiontMerger;
+import
org.apache.nifi.cluster.coordination.http.endpoints.FlowSnippetEndpointMerger;
+import
org.apache.nifi.cluster.coordination.http.endpoints.GroupStatusEndpointMerger;
+import
org.apache.nifi.cluster.coordination.http.endpoints.ListFlowFilesEndpointMerger;
+import
org.apache.nifi.cluster.coordination.http.endpoints.PortStatusEndpointMerger;
+import
org.apache.nifi.cluster.coordination.http.endpoints.ProcessGroupEndpointMerger;
+import
org.apache.nifi.cluster.coordination.http.endpoints.ProcessorEndpointMerger;
+import
org.apache.nifi.cluster.coordination.http.endpoints.ProcessorStatusEndpointMerger;
+import
org.apache.nifi.cluster.coordination.http.endpoints.ProcessorsEndpointMerger;
+import
org.apache.nifi.cluster.coordination.http.endpoints.ProvenanceEventEndpointMerger;
+import
org.apache.nifi.cluster.coordination.http.endpoints.ProvenanceQueryEndpointMerger;
+import
org.apache.nifi.cluster.coordination.http.endpoints.RemoteProcessGroupEndpointMerger;
+import
org.apache.nifi.cluster.coordination.http.endpoints.RemoteProcessGroupStatusEndpointMerger;
+import
org.apache.nifi.cluster.coordination.http.endpoints.RemoteProcessGroupsEndpointMerger;
+import
org.apache.nifi.cluster.coordination.http.endpoints.ReportingTaskEndpointMerger;
+import
org.apache.nifi.cluster.coordination.http.endpoints.ReportingTasksEndpointMerger;
+import
org.apache.nifi.cluster.coordination.http.endpoints.StatusHistoryEndpointMerger;
+import
org.apache.nifi.cluster.coordination.http.endpoints.SystemDiagnosticsEndpointMerger;
+import org.apache.nifi.cluster.manager.NodeResponse;
+import org.apache.nifi.stream.io.NullOutputStream;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class StandardHttpResponseMerger implements HttpResponseMerger {
+ private Logger logger =
LoggerFactory.getLogger(StandardHttpResponseMerger.class);
+ private static final List<EndpointResponseMerger> endpointMergers =
new ArrayList<>();
+
+ static {
+ endpointMergers.add(new ControllerStatusEndpointMerger());
+ endpointMergers.add(new GroupStatusEndpointMerger());
+ endpointMergers.add(new ProcessorStatusEndpointMerger());
+ endpointMergers.add(new ConnectionStatusEndpiontMerger());
+ endpointMergers.add(new PortStatusEndpointMerger());
+ endpointMergers.add(new RemoteProcessGroupStatusEndpointMerger());
+ endpointMergers.add(new ProcessorEndpointMerger());
+ endpointMergers.add(new ProcessorsEndpointMerger());
+ endpointMergers.add(new RemoteProcessGroupEndpointMerger());
+ endpointMergers.add(new RemoteProcessGroupsEndpointMerger());
+ endpointMergers.add(new ProcessGroupEndpointMerger());
+ endpointMergers.add(new FlowSnippetEndpointMerger());
+ endpointMergers.add(new ProvenanceQueryEndpointMerger());
+ endpointMergers.add(new ProvenanceEventEndpointMerger());
+ endpointMergers.add(new ControllerServiceEndpointMerger());
+ endpointMergers.add(new ControllerServicesEndpointMerger());
+ endpointMergers.add(new
ControllerServiceReferenceEndpointMerger());
+ endpointMergers.add(new ReportingTaskEndpointMerger());
+ endpointMergers.add(new ReportingTasksEndpointMerger());
+ endpointMergers.add(new DropRequestEndpiontMerger());
+ endpointMergers.add(new ListFlowFilesEndpointMerger());
+ endpointMergers.add(new ComponentStateEndpointMerger());
+ endpointMergers.add(new BulletinBoardEndpointMerger());
+ endpointMergers.add(new StatusHistoryEndpointMerger());
+ endpointMergers.add(new SystemDiagnosticsEndpointMerger());
+ endpointMergers.add(new CountersEndpointMerger());
+ }
+
+ @Override
+ public NodeResponse mergeResponses(final URI uri, final String
httpMethod, final Set<NodeResponse> nodeResponses) {
+ final boolean hasSuccess = hasSuccessfulResponse(nodeResponses);
+ if (!hasSuccess) {
+ // It doesn't really matter which response we choose, as all
are problematic.
+ final NodeResponse clientResponse =
nodeResponses.iterator().next();
+
+ // Drain the response from all nodes except for the 'chosen
one'. This ensures that we don't
+ // leave data lingering on the socket and ensures that we
don't consume the content of the response
+ // that we intend to respond with
+ drainResponses(nodeResponses, clientResponse);
+ return clientResponse;
+ }
+
+ // Determine which responses are successful
+ final Set<NodeResponse> successResponses =
nodeResponses.stream().filter(p -> p.is2xx()).collect(Collectors.toSet());
+ final Set<NodeResponse> problematicResponses =
nodeResponses.stream().filter(p -> !p.is2xx()).collect(Collectors.toSet());
+
+ // Choose any of the successful responses to be the 'chosen one'.
+ final NodeResponse clientResponse =
successResponses.iterator().next();
+
+ final EndpointResponseMerger merger =
getEndpointResponseMerger(uri, httpMethod);
+ if (merger == null) {
+ return clientResponse;
+ }
+
+ return merger.merge(uri, httpMethod, successResponses,
problematicResponses, clientResponse);
+ }
+
+ @Override
+ public Set<NodeResponse> getProblematicNodeResponses(final
Set<NodeResponse> allResponses) {
+ // Check if there are any 2xx responses
+ final boolean containsSuccessfulResponse =
hasSuccessfulResponse(allResponses);
+
+ if (containsSuccessfulResponse) {
+ // If there is a 2xx response, we consider a response to be
problematic if it is not 2xx
+ return allResponses.stream().filter(p ->
!p.is2xx()).collect(Collectors.toSet());
+ } else {
+ // If no node is successful, we consider a problematic
response to be only those that are 5xx
+ return allResponses.stream().filter(p ->
p.is5xx()).collect(Collectors.toSet());
+ }
--- End diff --
One of the benefits of functional programming is the ability to create a
reference to a function and then reuse it. So the above could be further
simplified by doing something like this:
```
Predicate<?> predicate = containsSuccessfulResponse ? p -> !p.is2xx() : p
-> p.is5xx()
return allResponses.stream().filter(predicate).collect(Collectors.toSet());
```
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