Clean up duplicate follow config parameter code (elastic#37688)

Introduced FollowParameters class that put follow, resume follow,
put auto follow pattern requests and follow info response classes reuse.

The FollowParameters class had the fields, getters etc. for the common parameters
that all these APIs have.  Also binary and xcontent serialization /
parsing is handled by this class.

The follow, resume follow, put auto follow pattern request classes originally
used optional non primitive fields, so FollowParameters has that too and the follow info api can handle that now too.

Also the followerIndex field can in production only be specified via
the url path. If it is also specified via the request body then
it must have the same value as is specified in the url path. This
option only existed to xcontent testing. However the AbstractSerializingTestCase
base class now also supports createXContextTestInstance() to provide
a different test instance when testing xcontent, so allowing followerIndex
to be specified via the request body is no longer needed.

By moving the followerIndex field from Body to ResumeFollowAction.Request
class and not allowing the followerIndex field to be specified via
the request body the Body class is redundant and can be removed. The
ResumeFollowAction.Request class can then directly use the
FollowParameters class.

For consistency I also removed the ability to specified followerIndex
in the put follow api and the name in put auto follow pattern api via
the request body.

client/rest-high-level/src/main/java/org/elasticsearch/client/ccr/PutFollowRequest.java

@@ -32,7 +32,6 @@ public final class PutFollowRequest extends FollowConfig implements Validatable,
 
     static final ParseField REMOTE_CLUSTER_FIELD = new ParseField("remote_cluster");
     static final ParseField LEADER_INDEX_FIELD = new ParseField("leader_index");
-    static final ParseField FOLLOWER_INDEX_FIELD = new ParseField("follower_index");
 
     private final String remoteCluster;
     private final String leaderIndex;
@@ -55,7 +54,6 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
         builder.startObject();
         builder.field(REMOTE_CLUSTER_FIELD.getPreferredName(), remoteCluster);
         builder.field(LEADER_INDEX_FIELD.getPreferredName(), leaderIndex);
-        builder.field(FOLLOWER_INDEX_FIELD.getPreferredName(), followerIndex);
         toXContentFragment(builder, params);
         builder.endObject();
         return builder;

client/rest-high-level/src/main/java/org/elasticsearch/client/ccr/ResumeFollowRequest.java

@@ -26,8 +26,6 @@
 import java.io.IOException;
 import java.util.Objects;
 
-import static org.elasticsearch.client.ccr.PutFollowRequest.FOLLOWER_INDEX_FIELD;
-
 public final class ResumeFollowRequest extends FollowConfig implements Validatable, ToXContentObject {
 
     private final String followerIndex;
@@ -39,7 +37,6 @@ public ResumeFollowRequest(String followerIndex) {
     @Override
     public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
         builder.startObject();
-        builder.field(FOLLOWER_INDEX_FIELD.getPreferredName(), followerIndex);
         toXContentFragment(builder, params);
         builder.endObject();
         return builder;

client/rest-high-level/src/test/java/org/elasticsearch/client/ccr/PutFollowRequestTests.java

@@ -31,12 +31,11 @@
 public class PutFollowRequestTests extends AbstractXContentTestCase<PutFollowRequest> {
 
     private static final ConstructingObjectParser<PutFollowRequest, Void> PARSER = new ConstructingObjectParser<>("test_parser",
-        true, (args) -> new PutFollowRequest((String) args[0], (String) args[1], (String) args[2]));
+        true, (args) -> new PutFollowRequest((String) args[0], (String) args[1], "followerIndex"));
 
     static {
         PARSER.declareString(ConstructingObjectParser.constructorArg(), PutFollowRequest.REMOTE_CLUSTER_FIELD);
         PARSER.declareString(ConstructingObjectParser.constructorArg(), PutFollowRequest.LEADER_INDEX_FIELD);
-        PARSER.declareString(ConstructingObjectParser.constructorArg(), PutFollowRequest.FOLLOWER_INDEX_FIELD);
         PARSER.declareInt(PutFollowRequest::setMaxReadRequestOperationCount, PutFollowRequest.MAX_READ_REQUEST_OPERATION_COUNT);
         PARSER.declareField(
             PutFollowRequest::setMaxReadRequestSize,
@@ -82,7 +81,7 @@ protected boolean supportsUnknownFields() {
     @Override
     protected PutFollowRequest createTestInstance() {
         PutFollowRequest putFollowRequest =
-            new PutFollowRequest(randomAlphaOfLength(4), randomAlphaOfLength(4), randomAlphaOfLength(4));
+            new PutFollowRequest(randomAlphaOfLength(4), randomAlphaOfLength(4), "followerIndex");
         if (randomBoolean()) {
             putFollowRequest.setMaxOutstandingReadRequests(randomIntBetween(0, Integer.MAX_VALUE));
         }

client/rest-high-level/src/test/java/org/elasticsearch/client/ccr/ResumeFollowRequestTests.java

@@ -21,7 +21,6 @@
 
 import org.elasticsearch.common.unit.ByteSizeValue;
 import org.elasticsearch.common.unit.TimeValue;
-import org.elasticsearch.common.xcontent.ConstructingObjectParser;
 import org.elasticsearch.common.xcontent.ObjectParser;
 import org.elasticsearch.common.xcontent.XContentParser;
 import org.elasticsearch.test.AbstractXContentTestCase;
@@ -30,11 +29,10 @@
 
 public class ResumeFollowRequestTests extends AbstractXContentTestCase<ResumeFollowRequest> {
 
-    private static final ConstructingObjectParser<ResumeFollowRequest, Void> PARSER = new ConstructingObjectParser<>("test_parser",
-        true, (args) -> new ResumeFollowRequest((String) args[0]));
+    private static final ObjectParser<ResumeFollowRequest, Void> PARSER = new ObjectParser<>("test_parser",
+        true, () -> new ResumeFollowRequest("followerIndex"));
 
     static {
-        PARSER.declareString(ConstructingObjectParser.constructorArg(), PutFollowRequest.FOLLOWER_INDEX_FIELD);
         PARSER.declareInt(ResumeFollowRequest::setMaxReadRequestOperationCount, FollowConfig.MAX_READ_REQUEST_OPERATION_COUNT);
         PARSER.declareField(
             ResumeFollowRequest::setMaxReadRequestSize,
@@ -79,7 +77,7 @@ protected boolean supportsUnknownFields() {
 
     @Override
     protected ResumeFollowRequest createTestInstance() {
-        ResumeFollowRequest resumeFollowRequest = new ResumeFollowRequest(randomAlphaOfLength(4));
+        ResumeFollowRequest resumeFollowRequest = new ResumeFollowRequest("followerIndex");
         if (randomBoolean()) {
             resumeFollowRequest.setMaxOutstandingReadRequests(randomIntBetween(0, Integer.MAX_VALUE));
         }

x-pack/plugin/ccr/src/main/java/org/elasticsearch/xpack/ccr/action/AutoFollowCoordinator.java

@@ -40,7 +40,6 @@
 import org.elasticsearch.xpack.core.ccr.AutoFollowMetadata.AutoFollowPattern;
 import org.elasticsearch.xpack.core.ccr.AutoFollowStats;
 import org.elasticsearch.xpack.core.ccr.action.PutFollowAction;
-import org.elasticsearch.xpack.core.ccr.action.ResumeFollowAction;
 
 import java.util.ArrayList;
 import java.util.Collections;
@@ -511,23 +510,20 @@ private void followLeaderIndex(String autoFollowPattenName,
             final String leaderIndexName = indexToFollow.getName();
             final String followIndexName = getFollowerIndexName(pattern, leaderIndexName);
 
-            ResumeFollowAction.Request followRequest = new ResumeFollowAction.Request();
-            followRequest.setFollowerIndex(followIndexName);
-            followRequest.setMaxReadRequestOperationCount(pattern.getMaxReadRequestOperationCount());
-            followRequest.setMaxReadRequestSize(pattern.getMaxReadRequestSize());
-            followRequest.setMaxOutstandingReadRequests(pattern.getMaxOutstandingReadRequests());
-            followRequest.setMaxWriteRequestOperationCount(pattern.getMaxWriteRequestOperationCount());
-            followRequest.setMaxWriteRequestSize(pattern.getMaxWriteRequestSize());
-            followRequest.setMaxOutstandingWriteRequests(pattern.getMaxOutstandingWriteRequests());
-            followRequest.setMaxWriteBufferCount(pattern.getMaxWriteBufferCount());
-            followRequest.setMaxWriteBufferSize(pattern.getMaxWriteBufferSize());
-            followRequest.setMaxRetryDelay(pattern.getMaxRetryDelay());
-            followRequest.setReadPollTimeout(pattern.getPollTimeout());
-
             PutFollowAction.Request request = new PutFollowAction.Request();
             request.setRemoteCluster(remoteCluster);
             request.setLeaderIndex(indexToFollow.getName());
-            request.setFollowRequest(followRequest);
+            request.setFollowerIndex(followIndexName);
+            request.getParameters().setMaxReadRequestOperationCount(pattern.getMaxReadRequestOperationCount());
+            request.getParameters().setMaxReadRequestSize(pattern.getMaxReadRequestSize());
+            request.getParameters().setMaxOutstandingReadRequests(pattern.getMaxOutstandingReadRequests());
+            request.getParameters().setMaxWriteRequestOperationCount(pattern.getMaxWriteRequestOperationCount());
+            request.getParameters().setMaxWriteRequestSize(pattern.getMaxWriteRequestSize());
+            request.getParameters().setMaxOutstandingWriteRequests(pattern.getMaxOutstandingWriteRequests());
+            request.getParameters().setMaxWriteBufferCount(pattern.getMaxWriteBufferCount());
+            request.getParameters().setMaxWriteBufferSize(pattern.getMaxWriteBufferSize());
+            request.getParameters().setMaxRetryDelay(pattern.getMaxRetryDelay());
+            request.getParameters().setReadPollTimeout(pattern.getPollTimeout());
 
             // Execute if the create and follow api call succeeds:
             Runnable successHandler = () -> {

x-pack/plugin/ccr/src/main/java/org/elasticsearch/xpack/ccr/action/Pre67PutFollow.java

@@ -72,7 +72,7 @@ protected Boolean newResponse(final boolean acknowledged) {
 
             @Override
             public ClusterState execute(final ClusterState currentState) throws Exception {
-                String followIndex = request.getFollowRequest().getFollowerIndex();
+                String followIndex = request.getFollowerIndex();
                 IndexMetaData currentIndex = currentState.metaData().index(followIndex);
                 if (currentIndex != null) {
                     throw new ResourceAlreadyExistsException(currentIndex.getIndex());
@@ -112,10 +112,10 @@ public ClusterState execute(final ClusterState currentState) throws Exception {
                 ClusterState updatedState = builder.build();
 
                 RoutingTable.Builder routingTableBuilder = RoutingTable.builder(updatedState.routingTable())
-                    .addAsNew(updatedState.metaData().index(request.getFollowRequest().getFollowerIndex()));
+                    .addAsNew(updatedState.metaData().index(request.getFollowerIndex()));
                 updatedState = allocationService.reroute(
                     ClusterState.builder(updatedState).routingTable(routingTableBuilder.build()).build(),
-                    "follow index [" + request.getFollowRequest().getFollowerIndex() + "] created");
+                    "follow index [" + request.getFollowerIndex() + "] created");
 
                 logger.info("[{}] creating index, cause [ccr_create_and_follow], shards [{}]/[{}]",
                     followIndex, followIMD.getNumberOfShards(), followIMD.getNumberOfReplicas());
@@ -126,10 +126,13 @@ public ClusterState execute(final ClusterState currentState) throws Exception {
     }
 
     private void initiateFollowing(final PutFollowAction.Request request, final ActionListener<PutFollowAction.Response> listener) {
-        activeShardsObserver.waitForActiveShards(new String[]{request.getFollowRequest().getFollowerIndex()},
+        activeShardsObserver.waitForActiveShards(new String[]{request.getFollowerIndex()},
             ActiveShardCount.DEFAULT, request.timeout(), result -> {
                 if (result) {
-                    client.execute(ResumeFollowAction.INSTANCE, request.getFollowRequest(), ActionListener.wrap(
+                    ResumeFollowAction.Request resumeFollowRequest = new ResumeFollowAction.Request();
+                    resumeFollowRequest.setFollowerIndex(request.getFollowerIndex());
+                    resumeFollowRequest.setParameters(request.getParameters());
+                    client.execute(ResumeFollowAction.INSTANCE, resumeFollowRequest, ActionListener.wrap(
                         r -> listener.onResponse(new PutFollowAction.Response(true, true, r.isAcknowledged())),
                         listener::onFailure
                     ));

x-pack/plugin/ccr/src/main/java/org/elasticsearch/xpack/ccr/action/TransportFollowInfoAction.java

@@ -23,7 +23,7 @@
 import org.elasticsearch.transport.TransportService;
 import org.elasticsearch.xpack.ccr.Ccr;
 import org.elasticsearch.xpack.core.ccr.action.FollowInfoAction;
-import org.elasticsearch.xpack.core.ccr.action.FollowInfoAction.Response.FollowParameters;
+import org.elasticsearch.xpack.core.ccr.action.FollowParameters;
 import org.elasticsearch.xpack.core.ccr.action.FollowInfoAction.Response.FollowerInfo;
 import org.elasticsearch.xpack.core.ccr.action.FollowInfoAction.Response.Status;
 
@@ -99,18 +99,17 @@ static List<FollowerInfo> getFollowInfos(List<String> concreteFollowerIndices, C
                 String leaderIndex = ccrCustomData.get(Ccr.CCR_CUSTOM_METADATA_LEADER_INDEX_NAME_KEY);
                 if (result.isPresent()) {
                     ShardFollowTask params = result.get();
-                    FollowParameters followParameters = new FollowParameters(
-                        params.getMaxReadRequestOperationCount(),
-                        params.getMaxReadRequestSize(),
-                        params.getMaxOutstandingReadRequests(),
-                        params.getMaxWriteRequestOperationCount(),
-                        params.getMaxWriteRequestSize(),
-                        params.getMaxOutstandingWriteRequests(),
-                        params.getMaxWriteBufferCount(),
-                        params.getMaxWriteBufferSize(),
-                        params.getMaxRetryDelay(),
-                        params.getReadPollTimeout()
-                    );
+                    FollowParameters followParameters = new FollowParameters();
+                    followParameters.setMaxOutstandingReadRequests(params.getMaxOutstandingReadRequests());
+                    followParameters.setMaxOutstandingWriteRequests(params.getMaxOutstandingWriteRequests());
+                    followParameters.setMaxReadRequestOperationCount(params.getMaxReadRequestOperationCount());
+                    followParameters.setMaxWriteRequestOperationCount(params.getMaxWriteRequestOperationCount());
+                    followParameters.setMaxReadRequestSize(params.getMaxReadRequestSize());
+                    followParameters.setMaxWriteRequestSize(params.getMaxWriteRequestSize());
+                    followParameters.setMaxWriteBufferCount(params.getMaxWriteBufferCount());
+                    followParameters.setMaxWriteBufferSize(params.getMaxWriteBufferSize());
+                    followParameters.setMaxRetryDelay(params.getMaxRetryDelay());
+                    followParameters.setReadPollTimeout(params.getReadPollTimeout());
                     followerInfos.add(new FollowerInfo(followerIndex, remoteCluster, leaderIndex, Status.ACTIVE, followParameters));
                 } else {
                     followerInfos.add(new FollowerInfo(followerIndex, remoteCluster, leaderIndex, Status.PAUSED, null));

x-pack/plugin/ccr/src/main/java/org/elasticsearch/xpack/ccr/action/TransportPutAutoFollowPatternAction.java

@@ -149,8 +149,7 @@ static ClusterState innerPut(PutAutoFollowPatternAction.Request request,
             markExistingIndicesAsAutoFollowedForNewPatterns(request.getLeaderIndexPatterns(), remoteClusterState.metaData(),
                 previousPattern, followedIndexUUIDs);
         } else {
-            markExistingIndicesAsAutoFollowed(request.getLeaderIndexPatterns(), remoteClusterState.metaData(),
-                followedIndexUUIDs);
+            markExistingIndicesAsAutoFollowed(request.getLeaderIndexPatterns(), remoteClusterState.metaData(), followedIndexUUIDs);
         }
 
         if (filteredHeaders != null) {
@@ -161,16 +160,16 @@ static ClusterState innerPut(PutAutoFollowPatternAction.Request request,
             request.getRemoteCluster(),
             request.getLeaderIndexPatterns(),
             request.getFollowIndexNamePattern(),
-            request.getMaxReadRequestOperationCount(),
-            request.getMaxReadRequestSize(),
-            request.getMaxConcurrentReadBatches(),
-            request.getMaxWriteRequestOperationCount(),
-            request.getMaxWriteRequestSize(),
-            request.getMaxConcurrentWriteBatches(),
-            request.getMaxWriteBufferCount(),
-            request.getMaxWriteBufferSize(),
-            request.getMaxRetryDelay(),
-            request.getReadPollTimeout());
+            request.getParameters().getMaxReadRequestOperationCount(),
+            request.getParameters().getMaxReadRequestSize(),
+            request.getParameters().getMaxOutstandingReadRequests(),
+            request.getParameters().getMaxWriteRequestOperationCount(),
+            request.getParameters().getMaxWriteRequestSize(),
+            request.getParameters().getMaxOutstandingWriteRequests(),
+            request.getParameters().getMaxWriteBufferCount(),
+            request.getParameters().getMaxWriteBufferSize(),
+            request.getParameters().getMaxRetryDelay(),
+            request.getParameters().getReadPollTimeout());
         patterns.put(request.getName(), autoFollowPattern);
         ClusterState.Builder newState = ClusterState.builder(localState);
         newState.metaData(MetaData.builder(localState.getMetaData())