io.reactivex.netty.contexts.RequestIdProvider Maven / Gradle / Ivy
/*
* Copyright 2014 Netflix, Inc.
*
* Licensed 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 io.reactivex.netty.contexts;
import io.netty.channel.ChannelHandlerContext;
import io.netty.util.AttributeMap;
/**
* All contexts held by {@link ContextsContainer} are specific to a request and in order to uniquiely identify a request
* we require an identifier. This interface defines the contract to provide a globally unique identifier for a request.
*
* @author Nitesh Kant
*/
public interface RequestIdProvider extends RequestIdGenerator {
/**
* Inspects the {@code keySupplier} or {@code context} to see if there is a request Id already defined for this
* request. If it is, then it returns the same, else returns {@code null}
* * This method is NOT idempotent
*
* @param keySupplier The key supplier where usually an externally defined request Id is present.
* @param channelAttributeMap Channel attribute map, normally obtained as {@link ChannelHandlerContext#channel()}
*
* @return The request Identified or {@code null} if none exists.
*/
String onServerRequest(ContextKeySupplier keySupplier, AttributeMap channelAttributeMap);
/**
* This is primarily for response-request correlation for protocols that support multiple requests on the same
* connection, eg: using HTTP pipelining.
* This method is NOT idempotent
*
*
* @param responseKeySupplier {@link ContextKeySupplier} for the response.
* @param channelAttributeMap Channel attribute map, normally obtained as {@link ChannelHandlerContext#channel()}
*
* @return The request id, if exists. {@code null} otherwise.
*/
String beforeServerResponse(ContextKeySupplier responseKeySupplier, AttributeMap channelAttributeMap);
/**
* This does the correlation between an inbound request and all outbound requests that are made during the
* processing of the same request.
* This method is NOT idempotent
*
* @param clientAttributeMap Client's channel attribute map, normally obtained as
* {@link ChannelHandlerContext#channel()}
*
* @return The request id, if exists. {@code null} otherwise.
*/
String beforeClientRequest(AttributeMap clientAttributeMap);
/**
* Specifies the request id to be used while receiving a response for a client.
* This method is NOT idempotent
*
* @param clientAttributeMap Client's channel attribute map, normally obtained as
* {@link ChannelHandlerContext#channel()}
*
* @return The request id, if exists. {@code null} otherwise.
*/
String onClientResponse(AttributeMap clientAttributeMap);
/**
* Name of the context key (to be obtained via {@link ContextKeySupplier}) that is to be used to transfer the
* request identifier from one machine to another.
*
* @return The name of the context key for request id.
*/
String getRequestIdContextKeyName();
}