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* 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.synapse.mediators.throttle;
import org.apache.axiom.om.OMElement;
import org.apache.neethi.PolicyEngine;
import org.apache.synapse.Mediator;
import org.apache.synapse.MessageContext;
import org.apache.synapse.transport.nhttp.NhttpConstants;
import org.apache.synapse.config.Entry;
import org.apache.synapse.core.axis2.Axis2MessageContext;
import org.apache.synapse.mediators.AbstractMediator;
import org.apache.axis2.context.ConfigurationContext;
import org.apache.axis2.clustering.context.Replicator;
import org.apache.axis2.clustering.ClusteringFault;
import org.apache.axis2.clustering.ClusterManager;
import org.wso2.throttle.*;
/**
* The Mediator for the throttling - Throtting will occur according to the ws-policy
* which is specified as the key for lookup from the registry or the inline policy
* Only support IP based throttling- Throotling can manage per IP using the throttle policy
*/
public class ThrottleMediator extends AbstractMediator {
/* The key for getting the throttling policy - key refers to a/an [registry] entry */
private String policyKey = null;
/* InLine policy object - XML */
private OMElement inLinePolicy = null;
/* The reference to the sequence which will execute when access is denied */
private String onRejectSeqKey = null;
/* The in-line sequence which will execute when access is denied */
private Mediator onRejectMediator = null;
/* The reference to the sequence which will execute when access is allowed */
private String onAcceptSeqKey = null;
/* The in-line sequence which will execute when access is allowed */
private Mediator onAcceptMediator = null;
/* The concurrect access control group id */
private String id;
/* Access rate controller - limit the remote caller access*/
private AccessRateController accessControler;
/* ConcurrentAccessController - limit the remote calleres concurrent access */
private ConcurrentAccessController concurrentAccessController = null;
/* The property key that used when the ConcurrentAccessController
look up from ConfigurationContext */
private String key;
/* Is this env. support clustering*/
private boolean isClusteringEnable = false;
/* The Throttle object - holds all runtime and configuration data */
private Throttle throttle;
/* Lock used to ensure thread-safe creation of the throttle */
private final Object throttleLock = new Object();
public ThrottleMediator() {
this.accessControler = new AccessRateController();
}
public boolean mediate(MessageContext synCtx) {
boolean traceOn = isTraceOn(synCtx);
boolean traceOrDebugOn = isTraceOrDebugOn(traceOn);
boolean isResponse = synCtx.isResponse();
ConfigurationContext cc;
org.apache.axis2.context.MessageContext axisMC;
if (traceOrDebugOn) {
traceOrDebug(traceOn, "Start : Throttle mediator");
if (traceOn && trace.isTraceEnabled()) {
trace.trace("Message : " + synCtx.getEnvelope());
}
}
// To ensure the creation of throttle is thread safe – It is possible create same throttle
// object multiple times by multiple threads.
synchronized (throttleLock) {
// get Axis2 MessageContext and ConfigurationContext
axisMC = ((Axis2MessageContext) synCtx).getAxis2MessageContext();
cc = axisMC.getConfigurationContext();
//To ensure check for clustering environment only happens one time
if ((throttle == null && !isResponse) || (isResponse
&& concurrentAccessController == null)) {
ClusterManager clusterManager = cc.getAxisConfiguration().getClusterManager();
if (clusterManager != null &&
clusterManager.getContextManager() != null) {
isClusteringEnable = true;
}
}
// Throttle only will be created ,if the massage flow is IN
if (!isResponse) {
//check the availability of the ConcurrentAccessControler
//if this is a clustered environment
if (isClusteringEnable) {
concurrentAccessController =
(ConcurrentAccessController) cc.getProperty(key);
}
// for request messages, read the policy for throttling and initialize
if (inLinePolicy != null) {
// this uses a static policy
if (throttle == null) { // only one time creation
if (traceOn && trace.isTraceEnabled()) {
trace.trace("Initializing using static throttling policy : "
+ inLinePolicy);
}
try {
// process the policy
throttle = ThrottlePolicyProcessor.processPolicy(
PolicyEngine.getPolicy(inLinePolicy));
//At this point concurrent access controller definitely 'null'
// f the clustering is disable.
//For a clustered environment,it is 'null' ,
//if this is the first instance on the cluster ,
// that message mediation has occurred through this mediator.
if (throttle != null && concurrentAccessController == null) {
concurrentAccessController =
throttle.getConcurrentAccessController();
if (concurrentAccessController != null) {
cc.setProperty(key, concurrentAccessController);
}
}
} catch (ThrottleException e) {
handleException("Error processing the throttling policy", e, synCtx);
}
}
} else if (policyKey != null) {
// If the policy has specified as a registry key.
// load or re-load policy from registry or local entry if not already available
Entry entry = synCtx.getConfiguration().getEntryDefinition(policyKey);
if (entry == null) {
handleException("Cannot find throttling policy using key : "
+ policyKey, synCtx);
} else {
boolean reCreate = false;
// if the key refers to a dynamic resource
if (entry.isDynamic()) {
if (!entry.isCached() || entry.isExpired()) {
reCreate = true;
}
}
if (reCreate || throttle == null) {
Object entryValue = synCtx.getEntry(policyKey);
if (entryValue == null) {
handleException(
"Null throttling policy returned by Entry : "
+ policyKey, synCtx);
} else {
if (!(entryValue instanceof OMElement)) {
handleException("Policy returned from key : " + policyKey +
" is not an OMElement", synCtx);
} else {
//Check for reload in a cluster environment –
// For clustered environment ,if the concurrent access controller
// is not null and throttle is not null , then must reload.
if (isClusteringEnable && concurrentAccessController != null
&& throttle != null) {
concurrentAccessController = null; // set null ,
// because need reload
}
try {
// Creates the throttle from the policy
throttle = ThrottlePolicyProcessor.processPolicy(
PolicyEngine.getPolicy((OMElement) entryValue));
//For non-clustered environment , must re-initiates
//For clustered environment,
//concurrent access controller is null ,
//then must re-initiates
if (throttle != null && (concurrentAccessController == null
|| !isClusteringEnable)) {
concurrentAccessController =
throttle.getConcurrentAccessController();
if (concurrentAccessController != null) {
cc.setProperty(key, concurrentAccessController);
} else {
cc.removeProperty(key);
}
}
} catch (ThrottleException e) {
handleException("Error processing the throttling policy",
e, synCtx);
}
}
}
}
}
}
} else {
// if the message flow path is OUT , then must lookp from ConfigurationContext -
// never create ,just get the existing one
concurrentAccessController =
(ConcurrentAccessController) cc.getProperty(key);
}
}
//perform concurrency throttling
boolean canAccess = doThrottleByConcurrency(isResponse, traceOrDebugOn, traceOn);
//if the access is success through concurrency throttle and if this is a request message
//then do access rate based throttling
if (throttle != null && !isResponse && canAccess) {
canAccess = throttleByAccessRate(synCtx, axisMC, cc, traceOrDebugOn, traceOn);
}
// all the replication functionality of the access rate based throttling handles by itself
// Just replicate the current state of ConcurrentAccessController
if (isClusteringEnable && concurrentAccessController != null) {
if (cc != null) {
try {
if (traceOrDebugOn) {
traceOrDebug(traceOn, "Going to replicates the " +
"states of the ConcurrentAccessController with key : " + key);
}
Replicator.replicate(cc);
} catch (ClusteringFault clusteringFault) {
handleException("Error during the replicating states ",
clusteringFault, synCtx);
}
}
}
if (canAccess) {
if (onAcceptSeqKey != null) {
Mediator mediator = synCtx.getSequence(onAcceptSeqKey);
if (mediator != null) {
return mediator.mediate(synCtx);
} else {
handleException("Unable to find onAccept sequence with key : "
+ onAcceptSeqKey, synCtx);
}
} else if (onAcceptMediator != null) {
return onAcceptMediator.mediate(synCtx);
} else {
return true;
}
} else {
if (onRejectSeqKey != null) {
Mediator mediator = synCtx.getSequence(onRejectSeqKey);
if (mediator != null) {
return mediator.mediate(synCtx);
} else {
handleException("Unable to find onReject sequence with key : "
+ onRejectSeqKey, synCtx);
}
} else if (onRejectMediator != null) {
return onRejectMediator.mediate(synCtx);
} else {
return false;
}
}
if (traceOrDebugOn) {
traceOrDebug(traceOn, "End : Throttle mediator");
}
return canAccess;
}
/**
* Helper method that handles the concurrent access through throttle
*
* @param isResponse Current Message is response or not
* @param traceOrDebugOn is trace or debug on?
* @param traceOn is trace on?
* @return true if the caller can access ,o.w. false
*/
private boolean doThrottleByConcurrency(boolean isResponse, boolean traceOrDebugOn, boolean traceOn) {
boolean canAcess = true;
if (concurrentAccessController != null) {
// do the concurrecy throttling
int concurrentLimit = concurrentAccessController.getLimit();
if (traceOrDebugOn) {
traceOrDebug(traceOn, "Concurrent access controller for ID : " + id +
" allows : " + concurrentLimit + " concurrent accesses");
}
int available;
if (!isResponse) {
available = concurrentAccessController.getAndDecrement();
canAcess = available > 0;
if (traceOrDebugOn) {
traceOrDebug(traceOn, "Concurrency Throttle : Access " +
(canAcess ? "allowed" : "denied") + " :: " + available
+ " of available of " + concurrentLimit + " connections");
}
} else {
available = concurrentAccessController.incrementAndGet();
if (traceOrDebugOn) {
traceOrDebug(traceOn, "Concurrency Throttle : Connection returned" + " :: " +
available + " of available of " + concurrentLimit + " connections");
}
}
}
return canAcess;
}
/**
* Helper method that handles the access-rate based throttling
*
* @param synCtx MessageContext(Synapse)
* @param axisMC MessageContext(Axis2)
* @param cc ConfigurationContext
* @param traceOrDebugOn is trace or debug on?
* @param traceOn is trace on?
* @return ue if the caller can access ,o.w. false
*/
private boolean throttleByAccessRate(MessageContext synCtx, org.apache.axis2.context.MessageContext axisMC, ConfigurationContext cc, boolean traceOrDebugOn, boolean traceOn) {
String callerId = null;
boolean canAccess = true;
//remote ip of the caller
String remoteIP = (String) axisMC.getPropertyNonReplicable(
org.apache.axis2.context.MessageContext.REMOTE_ADDR);
//domain name of the caller
String domainName = (String) axisMC.getPropertyNonReplicable(NhttpConstants.REMOTE_HOST);
//Using remote caller domain name , If there is a throttle configuration for
// this domain name ,then throttling will occur according to that configuration
if (domainName != null) {
// do the domain based throttling
if (traceOrDebugOn) {
traceOrDebug(traceOn, "The Domain Name of the caller is :" + domainName);
}
// loads the DomainBasedThrottleContext
ThrottleContext context
= throttle.getThrottleContext(ThrottleConstants.DOMAIN_BASED_THROTTLE_KEY);
if (context != null) {
//loads the DomainBasedThrottleConfiguration
ThrottleConfiguration config = context.getThrottleConfiguration();
if (config != null) {
//checks the availability of a policy configuration for this domain name
callerId = config.getConfigurationKeyOfCaller(domainName);
if (callerId != null) { // there is configuration for this domain name
//If this is a clusterred env.
if (isClusteringEnable) {
context.setConfigurationContext(cc);
context.setThrottleId(id);
}
try {
//Checks for access state
canAccess = accessControler.canAccess(context,
callerId, ThrottleConstants.DOMAIN_BASE);
if (traceOrDebugOn) {
traceOrDebug(traceOn, "Access " + (canAccess ? "allowed" : "denied")
+ " for Domain Name : " + domainName);
}
//In the case of both of concurrency throttling and
//rate based throttling have enabled ,
//if the access rate less than maximum concurrent access ,
//then it is possible to occur death situation.To avoid that reset,
//if the access has denied by rate based throttling
if (!canAccess && concurrentAccessController != null) {
concurrentAccessController.incrementAndGet();
if (isClusteringEnable) {
cc.setProperty(key, concurrentAccessController);
}
}
} catch (ThrottleException e) {
handleException("Error occurd during throttling", e, synCtx);
}
}
}
}
} else {
if (traceOrDebugOn) {
traceOrDebug(traceOn, "The Domain name of the caller cannot be found");
}
}
//At this point , any configuration for the remote caller hasn't found ,
//therefore trying to find a configuration policy based on remote caller ip
if (callerId == null) {
//do the IP-based throttling
if (remoteIP == null) {
if (traceOrDebugOn) {
traceOrDebug(traceOn, "The IP address of the caller cannot be found");
}
canAccess = true;
} else {
if (traceOrDebugOn) {
traceOrDebug(traceOn, "The IP Address of the caller is :" + remoteIP);
}
try {
// Loads the IPBasedThrottleContext
ThrottleContext context =
throttle.getThrottleContext(ThrottleConstants.IP_BASED_THROTTLE_KEY);
if (context != null) {
//Loads the IPBasedThrottleConfiguration
ThrottleConfiguration config = context.getThrottleConfiguration();
if (config != null) {
//Checks the availability of a policy configuration for this ip
callerId = config.getConfigurationKeyOfCaller(remoteIP);
if (callerId != null) { // there is configuration for this ip
//For clustered env.
if (isClusteringEnable) {
context.setConfigurationContext(cc);
context.setThrottleId(id);
}
//Checks access state
canAccess = accessControler.canAccess(context,
callerId, ThrottleConstants.IP_BASE);
if (traceOrDebugOn) {
traceOrDebug(traceOn, "Access " +
(canAccess ? "allowed" : "denied")
+ " for IP : " + remoteIP);
}
//In the case of both of concurrency throttling and
//rate based throttling have enabled ,
//if the access rate less than maximum concurrent access ,
//then it is possible to occur death situation.To avoid that reset,
//if the access has denied by rate based throttling
if (!canAccess && concurrentAccessController != null) {
concurrentAccessController.incrementAndGet();
if (isClusteringEnable) {
cc.setProperty(key, concurrentAccessController);
}
}
}
}
}
} catch (ThrottleException e) {
handleException("Error occurd during throttling", e, synCtx);
}
}
}
return canAccess;
}
public String getType() {
return ThrottleMediator.class.getName();
}
/**
* To get the policy key - The key for which will used to lookup policy from the registry
*
* @return String
*/
public String getPolicyKey() {
return policyKey;
}
/**
* To set the policy key - The key for which lookup from the registry
*
* @param policyKey Key for picking policy from the registry
*/
public void setPolicyKey(String policyKey) {
this.policyKey = policyKey;
}
/**
* getting throttle policy which has defined as InLineXML
*
* @return InLine Throttle Policy
*/
public OMElement getInLinePolicy() {
return inLinePolicy;
}
/**
* setting throttle policy which has defined as InLineXML
*
* @param inLinePolicy Inline policy
*/
public void setInLinePolicy(OMElement inLinePolicy) {
this.inLinePolicy = inLinePolicy;
}
public String getOnRejectSeqKey() {
return onRejectSeqKey;
}
public void setOnRejectSeqKey(String onRejectSeqKey) {
this.onRejectSeqKey = onRejectSeqKey;
}
public Mediator getOnRejectMediator() {
return onRejectMediator;
}
public void setOnRejectMediator(Mediator onRejectMediator) {
this.onRejectMediator = onRejectMediator;
}
public String getOnAcceptSeqKey() {
return onAcceptSeqKey;
}
public void setOnAcceptSeqKey(String onAcceptSeqKey) {
this.onAcceptSeqKey = onAcceptSeqKey;
}
public Mediator getOnAcceptMediator() {
return onAcceptMediator;
}
public void setOnAcceptMediator(Mediator onAcceptMediator) {
this.onAcceptMediator = onAcceptMediator;
}
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
this.key = ThrottleConstants.THROTTLE_PROPERTY_PREFIX + id + ThrottleConstants.CAC_SUFFIX;
}
}