一 处理链工厂函数
1.1 SlogChainProvider
- 静态初始化获取处理链工厂类
static final ServiceLoaderLOADER = ServiceLoader.load(SlotChainBuilder.class); - 可自定义处理链工厂，或使用默认工厂
- DefaultSlotChainBuilder默认工厂创建资源处理链
public ProcessorSlotChain build() {
ProcessorSlotChain chain = new DefaultProcessorSlotChain();
chain.addLast(new NodeSelectorSlot());
chain.addLast(new ClusterBuilderSlot());
chain.addLast(new LogSlot());
chain.addLast(new StatisticSlot());
chain.addLast(new SystemSlot());
chain.addLast(new AuthoritySlot());
chain.addLast(new FlowSlot());
chain.addLast(new DegradeSlot());
return chain;
}
二 处理链头节点
2.1 类关系
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2.2 AbstractLinkedProcessorSlot
- 所有处理链节点都继承AbstractLinkedProcessorSlot
- AbstractLinkedProcessorSlot内部有一个next属性，用于维持一个资源处理函数的单链表。
- 触发下一节点的entry函数调用
void fireEntry(Context context, ResourceWrapper resourceWrapper, Object obj, int count, boolean prioritized, Object... args) - 触发下一节点的exit函数调用
void fireExit(Context context, ResourceWrapper resourceWrapper, int count, Object... args);
2.3 DefaultProcessorSlotChain
- 提供链表节点前插入和后插入的接口
- 提供entry和exit函数调用接口，依次按顺序调用单链表上各节点的对应函数
三 处理链节点
- 每个资源一个处理链，即使在不同context上下文中
3.1 NodeSelectorSlot()
- 对于每个资源，为当前context上下文创建一个DefaultNode统计节点
- 记录节点父子关系，记录节点为context当前处理节点，即对当前请求资源进行统计。
public void entry(Context context, ResourceWrapper resourceWrapper, Object obj, int count, boolean prioritized, Object... args)
throws Throwable {
DefaultNode node = map.get(context.getName());
if (node == null) {
synchronized (this) {
node = map.get(context.getName());
if (node == null) {
node = Env.nodeBuilder.buildTreeNode(resourceWrapper, null);
HashMap cacheMap = new HashMap(map.size());
cacheMap.putAll(map);
cacheMap.put(context.getName(), node);
map = cacheMap;
}
// Build invocation tree
((DefaultNode)context.getLastNode()).addChild(node);
}
}
context.setCurNode(node);
fireEntry(context, resourceWrapper, node, count, prioritized, args);
}
3.2 ClusterBuilderSlot()
- 按资源名静态存储资源统计ClusterNode节点，即每个资源只创建一个对应ClusterNode
static volatile Map - 获取资源对应的ClusterNode，存储到当前context下资源的DefaultNode.clusterNode属性中
- 若指定了资源访问来源origin，则对资源的每个来源只创建一个StatisticNode统计该来源的资源请求数据。所有来源的统计节点存储在ClusterNode.originCountMap中。
Map
public void entry(Context context, ResourceWrapper resourceWrapper, DefaultNode node, int count,
boolean prioritized, Object... args)
throws Throwable {
if (clusterNode == null) {
synchronized (lock) {
if (clusterNode == null) {
// Create the cluster node.
clusterNode = Env.nodeBuilder.buildClusterNode();
HashMap newMap = new HashMap<>(Math.max(clusterNodeMap.size(), 16));
newMap.putAll(clusterNodeMap);
newMap.put(node.getId(), clusterNode);
clusterNodeMap = newMap;
}
}
}
node.setClusterNode(clusterNode);
if (!"".equals(context.getOrigin())) {
Node originNode = node.getClusterNode().getOrCreateOriginNode(context.getOrigin());
context.getCurEntry().setOriginNode(originNode);
}
fireEntry(context, resourceWrapper, node, count, prioritized, args);
}
3.3 LogSlot()
- 在资源请求时，记录请求失败日志，和请求异常日志
public void entry(Context context, ResourceWrapper resourceWrapper, DefaultNode obj, int count, boolean prioritized, Object... args)
throws Throwable {
try {
fireEntry(context, resourceWrapper, obj, count, prioritized, args);
} catch (BlockException e) {
EagleEyeLogUtil.log(resourceWrapper.getName(), e.getClass().getSimpleName(), e.getRuleLimitApp(),
context.getOrigin(), count);
throw e;
} catch (Throwable e) {
RecordLog.warn("Unexpected entry exception", e);
}
}
3.4 StatisticSlot()
3.4.1 请求时统计
- 先做后续资源请求判断，成功则添加成功统计，失败则添加失败统计
public void entry(Context context, ResourceWrapper resourceWrapper, DefaultNode node, int count,
boolean prioritized, Object... args) throws Throwable {
try {
// 先进行后续处理
fireEntry(context, resourceWrapper, node, count, prioritized, args);
// 资源请求成功，添加资源线程数，和资源使用数统计
//同时添加当前context上下文下的DefaultNode中的资源统计和资源唯一节点ClusterNode中的资源统计
node.increaseThreadNum();
node.addPassRequest(count);
if (context.getCurEntry().getOriginNode() != null) {
//根据调用来源添加资源请求统计数据
context.getCurEntry().getOriginNode().increaseThreadNum();
context.getCurEntry().getOriginNode().addPassRequest(count);
}
if (resourceWrapper.getType() == EntryType.IN) {
// 入口资源的统计增加
Constants.ENTRY_NODE.increaseThreadNum();
Constants.ENTRY_NODE.addPassRequest(count);
}
//资源请求成功后的回调函数调用
for (ProcessorSlotEntryCallback handler : StatisticSlotCallbackRegistry.getEntryCallbacks()) {
handler.onPass(context, resourceWrapper, node, count, args);
}
} catch (PriorityWaitException ex) {
node.increaseThreadNum();
if (context.getCurEntry().getOriginNode() != null) {
// Add count for origin node.
context.getCurEntry().getOriginNode().increaseThreadNum();
}
if (resourceWrapper.getType() == EntryType.IN) {
// Add count for global inbound entry node for global statistics.
Constants.ENTRY_NODE.increaseThreadNum();
}
// Handle pass event with registered entry callback handlers.
for (ProcessorSlotEntryCallback handler : StatisticSlotCallbackRegistry.getEntryCallbacks()) {
handler.onPass(context, resourceWrapper, node, count, args);
}
} catch (BlockException e) {
// Blocked, set block exception to current entry.
context.getCurEntry().setError(e);
// Add block count.
node.increaseBlockQps(count);
if (context.getCurEntry().getOriginNode() != null) {
context.getCurEntry().getOriginNode().increaseBlockQps(count);
}
if (resourceWrapper.getType() == EntryType.IN) {
// Add count for global inbound entry node for global statistics.
Constants.ENTRY_NODE.increaseBlockQps(count);
}
// Handle block event with registered entry callback handlers.
for (ProcessorSlotEntryCallback handler : StatisticSlotCallbackRegistry.getEntryCallbacks()) {
handler.onBlocked(e, context, resourceWrapper, node, count, args);
}
throw e;
} catch (Throwable e) {
// Unexpected error, set error to current entry.
context.getCurEntry().setError(e);
// This should not happen.
node.increaseExceptionQps(count);
if (context.getCurEntry().getOriginNode() != null) {
context.getCurEntry().getOriginNode().increaseExceptionQps(count);
}
if (resourceWrapper.getType() == EntryType.IN) {
Constants.ENTRY_NODE.increaseExceptionQps(count);
}
throw e;
}
}
3.4.2 释放资源时统计数据处理
- 请求成功则做一些统计数据处理
资源线程数-1，
记录资源持有时间，
存在来源配置则也记录指定来源的资源持有时间
入口类型，则更新入口节点统计 - exit回调函数调用
public void exit(Context context, ResourceWrapper resourceWrapper, int count, Object... args) {
DefaultNode node = (DefaultNode)context.getCurNode();
if (context.getCurEntry().getError() == null) {
// Calculate response time (max RT is TIME_DROP_VALVE).
long rt = TimeUtil.currentTimeMillis() - context.getCurEntry().getCreateTime();
if (rt > Constants.TIME_DROP_VALVE) {
rt = Constants.TIME_DROP_VALVE;
}
// Record response time and success count.
node.addRtAndSuccess(rt, count);
if (context.getCurEntry().getOriginNode() != null) {
context.getCurEntry().getOriginNode().addRtAndSuccess(rt, count);
}
node.decreaseThreadNum();
if (context.getCurEntry().getOriginNode() != null) {
context.getCurEntry().getOriginNode().decreaseThreadNum();
}
if (resourceWrapper.getType() == EntryType.IN) {
Constants.ENTRY_NODE.addRtAndSuccess(rt, count);
Constants.ENTRY_NODE.decreaseThreadNum();
}
} else {
// Error may happen.
}
// Handle exit event with registered exit callback handlers.
Collection exitCallbacks = StatisticSlotCallbackRegistry.getExitCallbacks();
for (ProcessorSlotExitCallback handler : exitCallbacks) {
handler.onExit(context, resourceWrapper, count, args);
}
fireExit(context, resourceWrapper, count);
}
3.5 SystemSlot()
- 系统级资源限流规则匹配，即EntryType.IN类型资源
public void entry(Context context, ResourceWrapper resourceWrapper, DefaultNode node, int count,
boolean prioritized, Object... args) throws Throwable {
SystemRuleManager.checkSystem(resourceWrapper);
fireEntry(context, resourceWrapper, node, count, prioritized, args);
}
3.6 AuthoritySlot()
- 授权规则匹配
public void entry(Context context, ResourceWrapper resourceWrapper, DefaultNode node, int count, boolean prioritized, Object... args)
throws Throwable {
checkBlackWhiteAuthority(resourceWrapper, context);
fireEntry(context, resourceWrapper, node, count, prioritized, args);
}
3.7 FlowSlot()
- 流控规则匹配
public void entry(Context context, ResourceWrapper resourceWrapper, DefaultNode node, int count,
boolean prioritized, Object... args) throws Throwable {
checkFlow(resourceWrapper, context, node, count, prioritized);
fireEntry(context, resourceWrapper, node, count, prioritized, args);
}
3.8 DegradeSlot()
- 降级规则匹配
public void entry(Context context, ResourceWrapper resourceWrapper, DefaultNode node, int count, boolean prioritized, Object... args)
throws Throwable {
DegradeRuleManager.checkDegrade(resourceWrapper, context, node, count);
fireEntry(context, resourceWrapper, node, count, prioritized, args);
}