com.alibaba.csp.sentinel.adapter.spring.webmvc.AbstractSentinelInterceptor Maven / Gradle / Ivy
/*
* Copyright 1999-2019 Alibaba Group Holding Ltd.
*
* 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
*
* https://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 com.alibaba.csp.sentinel.adapter.spring.webmvc;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.alibaba.csp.sentinel.Entry;
import com.alibaba.csp.sentinel.EntryType;
import com.alibaba.csp.sentinel.ResourceTypeConstants;
import com.alibaba.csp.sentinel.SphU;
import com.alibaba.csp.sentinel.Tracer;
import com.alibaba.csp.sentinel.adapter.spring.webmvc.config.BaseWebMvcConfig;
import com.alibaba.csp.sentinel.context.ContextUtil;
import com.alibaba.csp.sentinel.log.RecordLog;
import com.alibaba.csp.sentinel.slots.block.BlockException;
import com.alibaba.csp.sentinel.util.AssertUtil;
import com.alibaba.csp.sentinel.util.StringUtil;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;
/**
* Since request may be reprocessed in flow if any forwarding or including or other action
* happened (see {@link javax.servlet.ServletRequest#getDispatcherType()}) we will only
* deal with the initial request. So we use reference count to track in
* dispathing "onion" though which we could figure out whether we are in initial type "REQUEST".
* That means the sub-requests which we rarely meet in practice will NOT be recorded in Sentinel.
*
* How to implement a forward sub-request in your action:
*
* initalRequest() {
* ModelAndView mav = new ModelAndView();
* mav.setViewName("another");
* return mav;
* }
*
*
* @author kaizi2009
* @since 1.7.1
*/
public abstract class AbstractSentinelInterceptor implements HandlerInterceptor {
public static final String SENTINEL_SPRING_WEB_CONTEXT_NAME = "sentinel_spring_web_context";
private static final String EMPTY_ORIGIN = "";
private final BaseWebMvcConfig baseWebMvcConfig;
public AbstractSentinelInterceptor(BaseWebMvcConfig config) {
AssertUtil.notNull(config, "BaseWebMvcConfig should not be null");
AssertUtil.assertNotBlank(config.getRequestAttributeName(), "requestAttributeName should not be blank");
this.baseWebMvcConfig = config;
}
/**
* @param request
* @param rcKey
* @param step
* @return reference count after increasing (initial value as zero to be increased)
*/
private Integer increaseReferece(HttpServletRequest request, String rcKey, int step) {
Object obj = request.getAttribute(rcKey);
if (obj == null) {
// initial
obj = Integer.valueOf(0);
}
Integer newRc = (Integer)obj + step;
request.setAttribute(rcKey, newRc);
return newRc;
}
@Override
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
throws Exception {
try {
String resourceName = getResourceName(request);
if (StringUtil.isEmpty(resourceName)) {
return true;
}
if (increaseReferece(request, this.baseWebMvcConfig.getRequestRefName(), 1) != 1) {
return true;
}
// Parse the request origin using registered origin parser.
String origin = parseOrigin(request);
String contextName = getContextName(request);
ContextUtil.enter(contextName, origin);
Entry entry = SphU.entry(resourceName, ResourceTypeConstants.COMMON_WEB, EntryType.IN);
request.setAttribute(baseWebMvcConfig.getRequestAttributeName(), entry);
return true;
} catch (BlockException e) {
try {
handleBlockException(request, response, e);
} finally {
ContextUtil.exit();
}
return false;
}
}
/**
* Return the resource name of the target web resource.
*
* @param request web request
* @return the resource name of the target web resource.
*/
protected abstract String getResourceName(HttpServletRequest request);
/**
* Return the context name of the target web resource.
*
* @param request web request
* @return the context name of the target web resource.
*/
protected String getContextName(HttpServletRequest request) {
return SENTINEL_SPRING_WEB_CONTEXT_NAME;
}
@Override
public void afterCompletion(HttpServletRequest request, HttpServletResponse response,
Object handler, Exception ex) throws Exception {
if (increaseReferece(request, this.baseWebMvcConfig.getRequestRefName(), -1) != 0) {
return;
}
Entry entry = getEntryInRequest(request, baseWebMvcConfig.getRequestAttributeName());
if (entry == null) {
// should not happen
RecordLog.warn("[{}] No entry found in request, key: {}",
getClass().getSimpleName(), baseWebMvcConfig.getRequestAttributeName());
return;
}
traceExceptionAndExit(entry, ex);
removeEntryInRequest(request);
ContextUtil.exit();
}
@Override
public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,
ModelAndView modelAndView) throws Exception {
}
protected Entry getEntryInRequest(HttpServletRequest request, String attrKey) {
Object entryObject = request.getAttribute(attrKey);
return entryObject == null ? null : (Entry)entryObject;
}
protected void removeEntryInRequest(HttpServletRequest request) {
request.removeAttribute(baseWebMvcConfig.getRequestAttributeName());
}
protected void traceExceptionAndExit(Entry entry, Exception ex) {
if (entry != null) {
if (ex != null) {
Tracer.traceEntry(ex, entry);
}
entry.exit();
}
}
protected void handleBlockException(HttpServletRequest request, HttpServletResponse response, BlockException e)
throws Exception {
if (baseWebMvcConfig.getBlockExceptionHandler() != null) {
baseWebMvcConfig.getBlockExceptionHandler().handle(request, response, e);
} else {
// Throw BlockException directly. Users need to handle it in Spring global exception handler.
throw e;
}
}
protected String parseOrigin(HttpServletRequest request) {
String origin = EMPTY_ORIGIN;
if (baseWebMvcConfig.getOriginParser() != null) {
origin = baseWebMvcConfig.getOriginParser().parseOrigin(request);
if (StringUtil.isEmpty(origin)) {
return EMPTY_ORIGIN;
}
}
return origin;
}
}