com.alibaba.csp.sentinel.SphO Maven / Gradle / Ivy
/*
* Copyright 1999-2018 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
*
* 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 com.alibaba.csp.sentinel;
import java.lang.reflect.Method;
import java.util.List;
import com.alibaba.csp.sentinel.log.RecordLog;
import com.alibaba.csp.sentinel.context.ContextUtil;
import com.alibaba.csp.sentinel.slots.block.BlockException;
import com.alibaba.csp.sentinel.slots.block.Rule;
import com.alibaba.csp.sentinel.slots.block.degrade.DegradeRuleManager;
import com.alibaba.csp.sentinel.slots.block.flow.FlowRuleManager;
import com.alibaba.csp.sentinel.slots.system.SystemRule;
import com.alibaba.csp.sentinel.slots.system.SystemRuleManager;
/**
* Conceptually, physical or logical resource that need protection should be
* surrounded by an entry. The requests to this resource will be blocked if any
* criteria is met, eg. when any {@link Rule}'s threshold is exceeded. Once blocked,
* {@link SphO}#enter() will return false.
*
*
* To configure the criteria, we can use XXXRuleManager.loadRules() to add rules. eg.
* {@link FlowRuleManager#loadRules(List)}, {@link DegradeRuleManager#loadRules(List)},
* {@link SystemRuleManager#loadRules(List)}.
*
*
*
* Following code is an example. {@code "abc"} represent a unique name for the
* protected resource:
*
*
*
* public void foo() {
* if (SphO.entry("abc")) {
* try {
* // business logic
* } finally {
* SphO.exit(); // must exit()
* }
* } else {
* // failed to enter the protected resource.
* }
* }
*
*
* Make sure {@code SphO.entry()} and {@link SphO#exit()} be paired in the same thread,
* otherwise {@link ErrorEntryFreeException} will be thrown.
*
* @author jialiang.linjl
* @author leyou
* @see SphU
*/
public class SphO {
private static final Object[] OBJECTS0 = new Object[0];
/**
* Checking all {@link Rule}s about the resource.
*
* @param name the unique name of the protected resource
* @return true if no rule's threshold is exceeded, otherwise return false.
*/
public static boolean entry(String name) {
return entry(name, EntryType.OUT, 1, OBJECTS0);
}
/**
* Checking all {@link Rule}s about the protected method.
*
* @param method the protected method
* @return true if no rule's threshold is exceeded, otherwise return false.
*/
public static boolean entry(Method method) {
return entry(method, EntryType.OUT, 1, OBJECTS0);
}
/**
* Checking all {@link Rule}s about the protected method.
*
* @param method the protected method
* @param count tokens required
* @return true if no rule's threshold is exceeded, otherwise return false.
*/
public static boolean entry(Method method, int count) {
return entry(method, EntryType.OUT, count, OBJECTS0);
}
/**
* Checking all {@link Rule}s about the resource.
*
* @param name the unique string for the resource
* @param count tokens required
* @return true if no rule's threshold is exceeded, otherwise return false.
*/
public static boolean entry(String name, int count) {
return entry(name, EntryType.OUT, count, OBJECTS0);
}
/**
* Checking all {@link Rule}s about the protected method.
*
* @param method the protected method
* @param type the resource is an inbound or an outbound method. This is used
* to mark whether it can be blocked when the system is unstable,
* only inbound traffic could be blocked by {@link SystemRule}
* @return true if no rule's threshold is exceeded, otherwise return false.
*/
public static boolean entry(Method method, EntryType type) {
return entry(method, type, 1, OBJECTS0);
}
/**
* Checking all {@link Rule}s about the resource.
*
* @param name the unique name for the protected resource
* @param type the resource is an inbound or an outbound method. This is used
* to mark whether it can be blocked when the system is unstable,
* only inbound traffic could be blocked by {@link SystemRule}
* @return true if no rule's threshold is exceeded, otherwise return false.
*/
public static boolean entry(String name, EntryType type) {
return entry(name, type, 1, OBJECTS0);
}
/**
* Checking all {@link Rule}s about the protected method.
*
* @param method the protected method
* @param type the resource is an inbound or an outbound method. This is used
* to mark whether it can be blocked when the system is unstable,
* only inbound traffic could be blocked by {@link SystemRule}
* @param count tokens required
* @return true if no rule's threshold is exceeded, otherwise return false.
*/
public static boolean entry(Method method, EntryType type, int count) {
return entry(method, type, count, OBJECTS0);
}
/**
* Checking all {@link Rule}s about the resource.
*
* @param name the unique name for the protected resource
* @param type the resource is an inbound or an outbound method. This is used
* to mark whether it can be blocked when the system is unstable,
* only inbound traffic could be blocked by {@link SystemRule}
* @param count tokens required
* @return true if no rule's threshold is exceeded, otherwise return false.
*/
public static boolean entry(String name, EntryType type, int count) {
return entry(name, type, count, OBJECTS0);
}
/**
* Checking all {@link Rule}s about the resource.
*
* @param name the unique name for the protected resource
* @param type the resource is an inbound or an outbound method. This is used
* to mark whether it can be blocked when the system is unstable,
* only inbound traffic could be blocked by {@link SystemRule}
* @param count tokens required
* @param args extra parameters.
* @return true if no rule's threshold is exceeded, otherwise return false.
*/
public static boolean entry(String name, EntryType type, int count, Object... args) {
try {
Env.sph.entry(name, type, count, args);
} catch (BlockException e) {
return false;
} catch (Throwable e) {
RecordLog.info("[Sentinel] Fatal error", e);
return true;
}
return true;
}
/**
* Checking all {@link Rule}s about the protected method.
*
* @param method the protected method
* @param type the resource is an inbound or an outbound method. This is used
* to mark whether it can be blocked when the system is unstable,
* only inbound traffic could be blocked by {@link SystemRule}
* @param count tokens required
* @param args the parameters of the method.
* @return true if no rule's threshold is exceeded, otherwise return false.
*/
public static boolean entry(Method method, EntryType type, int count, Object... args) {
try {
Env.sph.entry(method, type, count, args);
} catch (BlockException e) {
return false;
} catch (Throwable e) {
RecordLog.info("[Sentinel] Fatal error", e);
return true;
}
return true;
}
public static void exit(int count, Object... args) {
ContextUtil.getContext().getCurEntry().exit(count, args);
}
public static void exit(int count) {
ContextUtil.getContext().getCurEntry().exit(count, OBJECTS0);
}
public static void exit() {
exit(1, OBJECTS0);
}
}
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