seanyu
3 years ago
parent
f6829e726e
commit
63c641848c
@ -0,0 +1,80 @@
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package com.tencent.cloud.polaris.circuitbreaker.feign;
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import java.io.IOException;
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import java.lang.reflect.Method;
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import java.nio.charset.StandardCharsets;
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import java.util.Collection;
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import java.util.Collections;
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import java.util.HashMap;
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import java.util.HashSet;
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import java.util.Map;
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import com.tencent.polaris.api.pojo.CircuitBreakerStatus;
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import com.tencent.polaris.circuitbreak.client.exception.CallAbortedException;
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import feign.Request;
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import feign.RequestTemplate;
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import feign.Response;
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import feign.codec.Decoder;
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import org.springframework.cloud.openfeign.FallbackFactory;
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public class PolarisCircuitBreakerFallbackFactory implements FallbackFactory {
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private final Decoder decoder;
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public PolarisCircuitBreakerFallbackFactory(Decoder decoder) {
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this.decoder = decoder;
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}
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@Override
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public Object create(Throwable t) {
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return new DefaultFallback(t, decoder);
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}
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public class DefaultFallback {
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private final Throwable t;
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private final Decoder decoder;
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public DefaultFallback(Throwable t, Decoder decoder) {
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this.t = t;
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this.decoder = decoder;
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}
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public Object fallback(Method method) {
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if (t instanceof CallAbortedException) {
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CircuitBreakerStatus.FallbackInfo fallbackInfo = ((CallAbortedException) t).getFallbackInfo();
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if (fallbackInfo != null) {
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Response.Builder responseBuilder = Response.builder()
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.status(fallbackInfo.getCode());
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if (fallbackInfo.getHeaders() != null) {
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Map<String, Collection<String>> headers = new HashMap<>();
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fallbackInfo.getHeaders().forEach((k, v) -> {
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if (headers.containsKey(k)) {
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headers.get(k).add(v);
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}
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else {
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headers.put(k, new HashSet<>(Collections.singleton(v)));
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}
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});
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responseBuilder.headers(headers);
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}
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if (fallbackInfo.getBody() != null) {
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responseBuilder.body(fallbackInfo.getBody(), StandardCharsets.UTF_8);
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}
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// Feign Response need a nonnull Request, which is not important in fallback response, so we create a fake one
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Request request = Request.create(Request.HttpMethod.GET, "/", new HashMap<>(), Request.Body.empty(), new RequestTemplate());
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responseBuilder.request(request);
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try (Response response = responseBuilder.build()) {
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return decoder.decode(response, method.getGenericReturnType());
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}
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catch (IOException e) {
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throw new IllegalStateException(e);
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}
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}
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}
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throw new IllegalStateException(t);
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}
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}
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}
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@ -0,0 +1,75 @@
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package com.tencent.cloud.polaris.circuitbreaker.feign;
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import feign.Feign;
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import feign.Target;
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import org.springframework.cloud.client.circuitbreaker.CircuitBreakerFactory;
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import org.springframework.cloud.openfeign.CircuitBreakerNameResolver;
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import org.springframework.cloud.openfeign.FallbackFactory;
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public class PolarisFeignCircuitBreaker {
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private PolarisFeignCircuitBreaker() {
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throw new IllegalStateException("Don't instantiate a utility class");
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}
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/**
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* @return builder for Feign CircuitBreaker integration
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*/
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public static PolarisFeignCircuitBreaker.Builder builder(Feign.Builder delegateBuilder) {
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return new PolarisFeignCircuitBreaker.Builder(delegateBuilder);
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}
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/**
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* Builder for Feign CircuitBreaker integration.
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*/
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public static final class Builder extends Feign.Builder {
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private final Feign.Builder delegateBuilder;
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public Builder(Feign.Builder delegateBuilder) {
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this.delegateBuilder = delegateBuilder;
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}
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private CircuitBreakerFactory circuitBreakerFactory;
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private String feignClientName;
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private CircuitBreakerNameResolver circuitBreakerNameResolver;
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public PolarisFeignCircuitBreaker.Builder circuitBreakerFactory(CircuitBreakerFactory circuitBreakerFactory) {
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this.circuitBreakerFactory = circuitBreakerFactory;
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return this;
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}
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public PolarisFeignCircuitBreaker.Builder feignClientName(String feignClientName) {
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this.feignClientName = feignClientName;
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return this;
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}
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public PolarisFeignCircuitBreaker.Builder circuitBreakerNameResolver(CircuitBreakerNameResolver circuitBreakerNameResolver) {
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this.circuitBreakerNameResolver = circuitBreakerNameResolver;
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return this;
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}
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public <T> T target(Target<T> target, T fallback) {
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return build(fallback != null ? new FallbackFactory.Default<T>(fallback) : null).newInstance(target);
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}
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public <T> T target(Target<T> target, FallbackFactory<? extends T> fallbackFactory) {
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return build(fallbackFactory).newInstance(target);
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}
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@Override
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public <T> T target(Target<T> target) {
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return build(null).newInstance(target);
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}
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public Feign build(final FallbackFactory<?> nullableFallbackFactory) {
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delegateBuilder.invocationHandlerFactory((target, dispatch) -> new PolarisFeignCircuitBreakerInvocationHandler(
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circuitBreakerFactory, feignClientName, target, dispatch, nullableFallbackFactory, circuitBreakerNameResolver, this.decoder));
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return delegateBuilder.build();
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}
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}
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}
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@ -0,0 +1,178 @@
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package com.tencent.cloud.polaris.circuitbreaker.feign;
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import java.lang.reflect.InvocationHandler;
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import java.lang.reflect.InvocationTargetException;
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import java.lang.reflect.Method;
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import java.lang.reflect.Proxy;
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import java.util.LinkedHashMap;
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import java.util.Map;
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import java.util.function.Function;
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import java.util.function.Supplier;
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import feign.InvocationHandlerFactory;
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import feign.Target;
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import feign.codec.Decoder;
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import org.springframework.cloud.client.circuitbreaker.CircuitBreaker;
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import org.springframework.cloud.client.circuitbreaker.CircuitBreakerFactory;
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import org.springframework.cloud.client.circuitbreaker.NoFallbackAvailableException;
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import org.springframework.cloud.openfeign.CircuitBreakerNameResolver;
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import org.springframework.cloud.openfeign.FallbackFactory;
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import org.springframework.web.context.request.RequestAttributes;
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import org.springframework.web.context.request.RequestContextHolder;
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import static feign.Util.checkNotNull;
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public class PolarisFeignCircuitBreakerInvocationHandler implements InvocationHandler {
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private final CircuitBreakerFactory factory;
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private final String feignClientName;
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private final Target<?> target;
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private final Map<Method, InvocationHandlerFactory.MethodHandler> dispatch;
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private final FallbackFactory<?> nullableFallbackFactory;
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private final Map<Method, Method> fallbackMethodMap;
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private final CircuitBreakerNameResolver circuitBreakerNameResolver;
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private final Decoder decoder;
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public PolarisFeignCircuitBreakerInvocationHandler(CircuitBreakerFactory factory, String feignClientName, Target<?> target,
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Map<Method, InvocationHandlerFactory.MethodHandler> dispatch, FallbackFactory<?> nullableFallbackFactory,
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CircuitBreakerNameResolver circuitBreakerNameResolver, Decoder decoder) {
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this.factory = factory;
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this.feignClientName = feignClientName;
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this.target = checkNotNull(target, "target");
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this.dispatch = checkNotNull(dispatch, "dispatch");
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this.fallbackMethodMap = toFallbackMethod(dispatch);
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this.nullableFallbackFactory = nullableFallbackFactory;
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this.circuitBreakerNameResolver = circuitBreakerNameResolver;
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this.decoder = decoder;
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}
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@Override
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public Object invoke(final Object proxy, final Method method, final Object[] args) throws Throwable {
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// early exit if the invoked method is from java.lang.Object
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// code is the same as ReflectiveFeign.FeignInvocationHandler
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if ("equals".equals(method.getName())) {
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try {
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Object otherHandler = args.length > 0 && args[0] != null ? Proxy.getInvocationHandler(args[0]) : null;
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return equals(otherHandler);
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}
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catch (IllegalArgumentException e) {
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return false;
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}
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}
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else if ("hashCode".equals(method.getName())) {
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return hashCode();
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}
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else if ("toString".equals(method.getName())) {
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return toString();
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}
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String circuitName = circuitBreakerNameResolver.resolveCircuitBreakerName(feignClientName, target, method);
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CircuitBreaker circuitBreaker = factory.create(circuitName);
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Supplier<Object> supplier = asSupplier(method, args);
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Function<Throwable, Object> fallbackFunction;
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if (this.nullableFallbackFactory != null) {
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fallbackFunction = throwable -> {
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Object fallback = this.nullableFallbackFactory.create(throwable);
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try {
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return this.fallbackMethodMap.get(method).invoke(fallback, args);
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}
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catch (Exception exception) {
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unwrapAndRethrow(exception);
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}
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return null;
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};
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}
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else {
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fallbackFunction = throwable -> {
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PolarisCircuitBreakerFallbackFactory.DefaultFallback fallback =
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(PolarisCircuitBreakerFallbackFactory.DefaultFallback) new PolarisCircuitBreakerFallbackFactory(this.decoder).create(throwable);
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return fallback.fallback(method);
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};
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}
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return circuitBreaker.run(supplier, fallbackFunction);
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}
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private void unwrapAndRethrow(Exception exception) {
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if (exception instanceof InvocationTargetException || exception instanceof NoFallbackAvailableException) {
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Throwable underlyingException = exception.getCause();
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if (underlyingException instanceof RuntimeException) {
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throw (RuntimeException) underlyingException;
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}
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if (underlyingException != null) {
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throw new IllegalStateException(underlyingException);
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}
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throw new IllegalStateException(exception);
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}
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}
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private Supplier<Object> asSupplier(final Method method, final Object[] args) {
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final RequestAttributes requestAttributes = RequestContextHolder.getRequestAttributes();
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final Thread caller = Thread.currentThread();
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return () -> {
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boolean isAsync = caller != Thread.currentThread();
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try {
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if (isAsync) {
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RequestContextHolder.setRequestAttributes(requestAttributes);
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}
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return dispatch.get(method).invoke(args);
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}
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catch (RuntimeException throwable) {
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throw throwable;
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}
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catch (Throwable throwable) {
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throw new RuntimeException(throwable);
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}
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finally {
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if (isAsync) {
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RequestContextHolder.resetRequestAttributes();
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}
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}
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};
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}
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/**
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* If the method param of {@link InvocationHandler#invoke(Object, Method, Object[])}
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* is not accessible, i.e in a package-private interface, the fallback call will cause
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* of access restrictions. But methods in dispatch are copied methods. So setting
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* access to dispatch method doesn't take effect to the method in
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* InvocationHandler.invoke. Use map to store a copy of method to invoke the fallback
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* to bypass this and reducing the count of reflection calls.
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* @return cached methods map for fallback invoking
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*/
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static Map<Method, Method> toFallbackMethod(Map<Method, InvocationHandlerFactory.MethodHandler> dispatch) {
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Map<Method, Method> result = new LinkedHashMap<>();
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for (Method method : dispatch.keySet()) {
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method.setAccessible(true);
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result.put(method, method);
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}
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return result;
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}
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@Override
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public boolean equals(Object obj) {
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if (obj instanceof PolarisFeignCircuitBreakerInvocationHandler) {
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PolarisFeignCircuitBreakerInvocationHandler other = (PolarisFeignCircuitBreakerInvocationHandler) obj;
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return this.target.equals(other.target);
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}
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return false;
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}
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@Override
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public int hashCode() {
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return this.target.hashCode();
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}
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@Override
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public String toString() {
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return this.target.toString();
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}
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}
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@ -0,0 +1,82 @@
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package com.tencent.cloud.polaris.circuitbreaker.feign;
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import feign.Feign;
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import feign.Target;
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import org.springframework.cloud.client.circuitbreaker.CircuitBreakerFactory;
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import org.springframework.cloud.openfeign.CircuitBreakerNameResolver;
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import org.springframework.cloud.openfeign.FallbackFactory;
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import org.springframework.cloud.openfeign.FeignCircuitBreaker;
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import org.springframework.cloud.openfeign.FeignClientFactoryBean;
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import org.springframework.cloud.openfeign.FeignContext;
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import org.springframework.cloud.openfeign.Targeter;
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import org.springframework.util.StringUtils;
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public class PolarisFeignCircuitBreakerTargeter implements Targeter {
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private final CircuitBreakerFactory circuitBreakerFactory;
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private final CircuitBreakerNameResolver circuitBreakerNameResolver;
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public PolarisFeignCircuitBreakerTargeter(CircuitBreakerFactory circuitBreakerFactory, CircuitBreakerNameResolver circuitBreakerNameResolver) {
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this.circuitBreakerFactory = circuitBreakerFactory;
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this.circuitBreakerNameResolver = circuitBreakerNameResolver;
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}
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@Override
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public <T> T target(FeignClientFactoryBean factory, Feign.Builder feign, FeignContext context,
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Target.HardCodedTarget<T> target) {
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if (!(feign instanceof FeignCircuitBreaker.Builder)) {
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return feign.target(target);
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}
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PolarisFeignCircuitBreaker.Builder builder = PolarisFeignCircuitBreaker.builder(feign);
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String name = !StringUtils.hasText(factory.getContextId()) ? factory.getName() : factory.getContextId();
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Class<?> fallback = factory.getFallback();
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if (fallback != void.class) {
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return targetWithFallback(name, context, target, builder, fallback);
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}
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Class<?> fallbackFactory = factory.getFallbackFactory();
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if (fallbackFactory != void.class) {
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return targetWithFallbackFactory(name, context, target, builder, fallbackFactory);
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}
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return builder(name, builder).target(target);
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}
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private <T> T targetWithFallbackFactory(String feignClientName, FeignContext context,
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Target.HardCodedTarget<T> target, PolarisFeignCircuitBreaker.Builder builder, Class<?> fallbackFactoryClass) {
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FallbackFactory<? extends T> fallbackFactory = (FallbackFactory<? extends T>) getFromContext("fallbackFactory",
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feignClientName, context, fallbackFactoryClass, FallbackFactory.class);
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return builder(feignClientName, builder).target(target, fallbackFactory);
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}
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private <T> T targetWithFallback(String feignClientName, FeignContext context, Target.HardCodedTarget<T> target,
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PolarisFeignCircuitBreaker.Builder builder, Class<?> fallback) {
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T fallbackInstance = getFromContext("fallback", feignClientName, context, fallback, target.type());
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return builder(feignClientName, builder).target(target, fallbackInstance);
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}
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private <T> T getFromContext(String fallbackMechanism, String feignClientName, FeignContext context,
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Class<?> beanType, Class<T> targetType) {
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Object fallbackInstance = context.getInstance(feignClientName, beanType);
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if (fallbackInstance == null) {
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throw new IllegalStateException(
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String.format("No " + fallbackMechanism + " instance of type %s found for feign client %s",
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beanType, feignClientName));
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}
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if (!targetType.isAssignableFrom(beanType)) {
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throw new IllegalStateException(String.format("Incompatible " + fallbackMechanism
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+ " instance. Fallback/fallbackFactory of type %s is not assignable to %s for feign client %s",
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beanType, targetType, feignClientName));
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}
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return (T) fallbackInstance;
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}
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private PolarisFeignCircuitBreaker.Builder builder(String feignClientName, PolarisFeignCircuitBreaker.Builder builder) {
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return builder
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.circuitBreakerFactory(circuitBreakerFactory)
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.feignClientName(feignClientName)
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.circuitBreakerNameResolver(circuitBreakerNameResolver);
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}
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}
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@ -1,34 +1,34 @@
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///*
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// * Tencent is pleased to support the open source community by making Spring Cloud Tencent available.
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// *
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// * Copyright (C) 2019 THL A29 Limited, a Tencent company. All rights reserved.
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// *
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// * Licensed under the BSD 3-Clause License (the "License");
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// * you may not use this file except in compliance with the License.
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// * You may obtain a copy of the License at
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// *
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// * https://opensource.org/licenses/BSD-3-Clause
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// *
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// * Unless required by applicable law or agreed to in writing, software distributed
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// * under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
|
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// * CONDITIONS OF ANY KIND, either express or implied. See the License for the
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// * specific language governing permissions and limitations under the License.
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// */
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//
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//package com.tencent.cloud.polaris.circuitbreaker.feign.example;
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//
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//import org.springframework.stereotype.Component;
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//
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///**
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// * Circuit breaker example callee fallback.
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// *
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// * @author sean yu
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// */
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//@Component
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//public class ProviderBFallback implements ProviderB {
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//
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// @Override
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// public String info() {
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// return "fallback: trigger the refuse for service b";
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// }
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//}
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/*
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* Tencent is pleased to support the open source community by making Spring Cloud Tencent available.
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*
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* Copyright (C) 2019 THL A29 Limited, a Tencent company. All rights reserved.
|
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*
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* Licensed under the BSD 3-Clause License (the "License");
|
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
|
||||
*
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* https://opensource.org/licenses/BSD-3-Clause
|
||||
*
|
||||
* 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.
|
||||
*/
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package com.tencent.cloud.polaris.circuitbreaker.feign.example;
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||||
|
||||
import org.springframework.stereotype.Component;
|
||||
|
||||
/**
|
||||
* Circuit breaker example callee fallback.
|
||||
*
|
||||
* @author sean yu
|
||||
*/
|
||||
@Component
|
||||
public class ProviderBFallback implements ProviderBWithFallback {
|
||||
|
||||
@Override
|
||||
public String info() {
|
||||
return "fallback: trigger the refuse for service b";
|
||||
}
|
||||
}
|
||||
|
||||
@ -0,0 +1,17 @@
|
||||
package com.tencent.cloud.polaris.circuitbreaker.feign.example;
|
||||
|
||||
import org.springframework.cloud.openfeign.FeignClient;
|
||||
import org.springframework.web.bind.annotation.GetMapping;
|
||||
|
||||
@FeignClient(name = "polaris-circuitbreaker-callee-service", contextId = "use-code-fallback", fallback = ProviderBFallback.class)
|
||||
public interface ProviderBWithFallback {
|
||||
|
||||
/**
|
||||
* Get info of service B.
|
||||
*
|
||||
* @return info of service B
|
||||
*/
|
||||
@GetMapping("/example/service/b/info")
|
||||
String info();
|
||||
|
||||
}
|
||||
Loading…
Reference in new issue