org.elasticsearch.plugins.ActionPlugin Maven / Gradle / Ivy
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* Licensed to Elasticsearch under one or more contributor
* license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright
* ownership. Elasticsearch 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.elasticsearch.plugins;
import org.elasticsearch.action.ActionType;
import org.elasticsearch.action.ActionRequest;
import org.elasticsearch.action.ActionResponse;
import org.elasticsearch.action.RequestValidators;
import org.elasticsearch.action.admin.indices.alias.IndicesAliasesRequest;
import org.elasticsearch.action.admin.indices.mapping.put.PutMappingRequest;
import org.elasticsearch.action.support.ActionFilter;
import org.elasticsearch.action.support.TransportAction;
import org.elasticsearch.action.support.TransportActions;
import org.elasticsearch.cluster.metadata.IndexNameExpressionResolver;
import org.elasticsearch.cluster.node.DiscoveryNodes;
import org.elasticsearch.common.Strings;
import org.elasticsearch.common.settings.ClusterSettings;
import org.elasticsearch.common.settings.IndexScopedSettings;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.common.settings.SettingsFilter;
import org.elasticsearch.common.util.concurrent.ThreadContext;
import org.elasticsearch.rest.RestController;
import org.elasticsearch.rest.RestHandler;
import org.elasticsearch.rest.RestHeaderDefinition;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
import java.util.Objects;
import java.util.function.Supplier;
import java.util.function.UnaryOperator;
import java.util.stream.Collectors;
/**
* An additional extension point for {@link Plugin}s that extends Elasticsearch's scripting functionality. Implement it like this:
* {@code
* {@literal @}Override
* public List> getActions() {
* return Arrays.asList(new ActionHandler<>(ReindexAction.INSTANCE, TransportReindexAction.class),
* new ActionHandler<>(UpdateByQueryAction.INSTANCE, TransportUpdateByQueryAction.class),
* new ActionHandler<>(DeleteByQueryAction.INSTANCE, TransportDeleteByQueryAction.class),
* new ActionHandler<>(RethrottleAction.INSTANCE, TransportRethrottleAction.class));
* }
* }
*/
public interface ActionPlugin {
/**
* Actions added by this plugin.
*/
default List> getActions() {
return Collections.emptyList();
}
/**
* Client actions added by this plugin. This defaults to all of the {@linkplain ActionType} in
* {@linkplain ActionPlugin#getActions()}.
*/
default List> getClientActions() {
return getActions().stream().map(a -> a.action).collect(Collectors.toList());
}
/**
* ActionType filters added by this plugin.
*/
default List getActionFilters() {
return Collections.emptyList();
}
/**
* Rest handlers added by this plugin.
*/
default List getRestHandlers(Settings settings, RestController restController, ClusterSettings clusterSettings,
IndexScopedSettings indexScopedSettings, SettingsFilter settingsFilter,
IndexNameExpressionResolver indexNameExpressionResolver, Supplier nodesInCluster) {
return Collections.emptyList();
}
/**
* Returns headers which should be copied through rest requests on to internal requests.
*/
default Collection getRestHeaders() {
return Collections.emptyList();
}
/**
* Returns headers which should be copied from internal requests into tasks.
*/
default Collection getTaskHeaders() {
return Collections.emptyList();
}
/**
* Returns a function used to wrap each rest request before handling the request.
* The returned {@link UnaryOperator} is called for every incoming rest request and receives
* the original rest handler as it's input. This allows adding arbitrary functionality around
* rest request handlers to do for instance logging or authentication.
* A simple example of how to only allow GET request is here:
*
* {@code
* UnaryOperator getRestHandlerWrapper(ThreadContext threadContext) {
* return originalHandler -> (RestHandler) (request, channel, client) -> {
* if (request.method() != Method.GET) {
* throw new IllegalStateException("only GET requests are allowed");
* }
* originalHandler.handleRequest(request, channel, client);
* };
* }
* }
*
*
* Note: Only one installed plugin may implement a rest wrapper.
*/
default UnaryOperator getRestHandlerWrapper(ThreadContext threadContext) {
return null;
}
final class ActionHandler {
private final ActionType action;
private final Class> transportAction;
private final Class[] supportTransportActions;
/**
* Create a record of an action, the {@linkplain TransportAction} that handles it, and any supporting {@linkplain TransportActions}
* that are needed by that {@linkplain TransportAction}.
*/
public ActionHandler(ActionType action, Class> transportAction,
Class... supportTransportActions) {
this.action = action;
this.transportAction = transportAction;
this.supportTransportActions = supportTransportActions;
}
public ActionType getAction() {
return action;
}
public Class> getTransportAction() {
return transportAction;
}
public Class[] getSupportTransportActions() {
return supportTransportActions;
}
@Override
public String toString() {
StringBuilder b = new StringBuilder().append(action.name()).append(" is handled by ").append(transportAction.getName());
if (supportTransportActions.length > 0) {
b.append('[').append(Strings.arrayToCommaDelimitedString(supportTransportActions)).append(']');
}
return b.toString();
}
@Override
public boolean equals(Object obj) {
if (obj == null || obj.getClass() != ActionHandler.class) {
return false;
}
ActionHandler other = (ActionHandler) obj;
return Objects.equals(action, other.action)
&& Objects.equals(transportAction, other.transportAction)
&& Objects.deepEquals(supportTransportActions, other.supportTransportActions);
}
@Override
public int hashCode() {
return Objects.hash(action, transportAction, supportTransportActions);
}
}
/**
* Returns a collection of validators that are used by {@link RequestValidators} to validate a
* {@link org.elasticsearch.action.admin.indices.mapping.put.PutMappingRequest} before the executing it.
*/
default Collection> mappingRequestValidators() {
return Collections.emptyList();
}
default Collection> indicesAliasesRequestValidators() {
return Collections.emptyList();
}
}