Provide an alternate naming convention for CB ids to allow for configuration via configuration properties

Configuration properties cannot contain characters like hash, parens, or commas

Author: Ryan Baxter

docs/src/main/asciidoc/spring-cloud-openfeign.adoc

@@ -372,6 +372,47 @@ public class FooConfiguration {
 
 To enable Spring Cloud CircuitBreaker group set the `feign.circuitbreaker.group.enabled` property to `true` (by default `false`).
 
+[[spring-clou-feign-circuitbreaker-configurationproperties]]
+=== Configuring CircuitBreakers With Configuration Properties
+
+You can configure CircuitBreakers via configuration properties.  To do set
+`feign.circuitbreaker.alphanumericCircuitBreakerNameResolver.enabled` to `true`.  Since
+you cannot use characters like `#`, `(`, `)` `,` in configuration property names we need to
+change the naming convention for the ids of the circuit breakers generated by OpenFeign.  The above
+property will do this for you.
+
+For example, if you had this Feign client
+
+[source,java,indent=0]
+----
+@FeignClienturl = "http://localhost:8080")
+public interface DemoClient {
+
+    @GetMapping("demo")
+    String getDemo();
+}
+----
+
+You could configure it using configuration properties by doing the following
+
+[source,yaml,indent=0]
+----
+feign:
+  circuitbreaker:
+    enabled: true
+    alphanumericCircuitBreakerNameResolver:
+      enabled: true
+resilience4j:
+  circuitbreaker:
+    instances:
+      DemoClientgetDemo:
+        minimumNumberOfCalls: 69
+  timelimiter:
+    instances:
+      DemoClientgetDemo:
+        timeoutDuration: 10s
+----
+
 
 [[spring-cloud-feign-circuitbreaker-fallback]]
 === Feign Spring Cloud CircuitBreaker Fallbacks

spring-cloud-openfeign-core/src/main/java/org/springframework/cloud/openfeign/FeignAutoConfiguration.java

@@ -166,10 +166,20 @@ public Targeter defaultFeignTargeter() {
 
 		@Bean
 		@ConditionalOnMissingBean(CircuitBreakerNameResolver.class)
+		@ConditionalOnProperty(value = "feign.circuitbreaker.alphanumericNames.enabled",
+				havingValue = "false", matchIfMissing = true)
 		public CircuitBreakerNameResolver circuitBreakerNameResolver() {
 			return new DefaultCircuitBreakerNameResolver();
 		}
 
+		@Bean
+		@ConditionalOnMissingBean(CircuitBreakerNameResolver.class)
+		@ConditionalOnProperty(value = "feign.circuitbreaker.alphanumericNames.enabled",
+				havingValue = "true")
+		public CircuitBreakerNameResolver alphanumericCircuitBreakerNameResolver() {
+			return new AlphanumericCircuitBreakerNameResolver();
+		}
+
 		@Bean
 		@ConditionalOnMissingBean
 		@ConditionalOnBean(CircuitBreakerFactory.class)
@@ -189,6 +199,15 @@ public String resolveCircuitBreakerName(String feignClientName, Target<?> target
 
 		}
 
+		static class AlphanumericCircuitBreakerNameResolver extends DefaultCircuitBreakerNameResolver {
+
+			@Override
+			public String resolveCircuitBreakerName(String feignClientName, Target<?> target, Method method) {
+				return super.resolveCircuitBreakerName(feignClientName, target, method).replaceAll("[^a-zA-Z0-9]", "");
+			}
+
+		}
+
 	}
 
 	// the following configuration is for alternate feign clients if

spring-cloud-openfeign-core/src/test/java/org/springframework/cloud/openfeign/circuitbreaker/CircuitBreakerAutoConfigurationTests.java

@@ -0,0 +1,79 @@
+/*
+ * Copyright 2013-2022 the original author or authors.
+ *
+ * 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 org.springframework.cloud.openfeign.circuitbreaker;
+
+import feign.Target;
+import org.junit.jupiter.api.Nested;
+import org.junit.jupiter.api.Test;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.cloud.openfeign.CircuitBreakerNameResolver;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+/**
+ * @author Ryan Baxter
+ */
+public class CircuitBreakerAutoConfigurationTests {
+
+	@SpringBootTest(classes = CircuitBreakerTests.Application.class,
+			webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT,
+			value = { "spring.application.name=springcircuittest", "spring.jmx.enabled=false",
+					"feign.circuitbreaker.enabled=true" })
+	@Nested
+	class DefaultNamingStrategy {
+
+		@Autowired
+		CircuitBreakerNameResolver nameResolver;
+
+		@Test
+		public void assertDefaultNamingStrategy() throws Exception {
+			Target target = mock(Target.class);
+			when(target.type()).thenReturn(CircuitBreakerTests.TestClientWithFactory.class);
+			assertThat(nameResolver.resolveCircuitBreakerName("foo", target,
+					CircuitBreakerTests.TestClientWithFactory.class.getMethod("getHello")))
+							.isEqualTo("TestClientWithFactory#getHello()");
+		}
+
+	}
+
+	@SpringBootTest(classes = CircuitBreakerTests.Application.class,
+			webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT,
+			value = { "spring.application.name=springcircuittest", "spring.jmx.enabled=false",
+					"feign.circuitbreaker.enabled=true",
+					"feign.circuitbreaker.alphanumericNames.enabled=true" })
+	@Nested
+	class AlphanumericNamingStrategy {
+
+		@Autowired
+		CircuitBreakerNameResolver nameResolver;
+
+		@Test
+		public void assertAlphanumericNamingStrategy() throws Exception {
+			Target target = mock(Target.class);
+			when(target.type()).thenReturn(CircuitBreakerTests.TestClientWithFactory.class);
+			assertThat(nameResolver.resolveCircuitBreakerName("foo", target,
+					CircuitBreakerTests.TestClientWithFactory.class.getMethod("getHello")))
+							.isEqualTo("TestClientWithFactorygetHello");
+		}
+
+	}
+
+}