Replace swagger urls in org.springdoc.core.properties.AbstractSwaggerUiConfigProperties#urls only if url is changed. Test to check if the issue is fixed. Fixes #2509.

springdoc-openapi-starter-common/src/main/java/org/springdoc/ui/AbstractSwaggerWelcome.java

@@ -33,6 +33,8 @@
 import org.springframework.util.CollectionUtils;
 import org.springframework.web.util.UriComponentsBuilder;
 
+import java.util.Objects;
+
 import static org.springdoc.core.utils.Constants.SWAGGER_UI_OAUTH_REDIRECT_URL;
 import static org.springdoc.core.utils.Constants.SWAGGER_UI_URL;
 import static org.springframework.util.AntPathMatcher.DEFAULT_PATH_SEPARATOR;
@@ -134,12 +136,18 @@ else if (swaggerUiConfigParameters.isValidUrl(swaggerUiUrl))
 			else
 				swaggerUiConfigParameters.addUrl(apiDocsUrl);
 			if (!CollectionUtils.isEmpty(swaggerUiConfig.getUrls())) {
-				swaggerUiConfig.cloneUrls().forEach(swaggerUrl -> {
-					swaggerUiConfigParameters.getUrls().remove(swaggerUrl);
-					if (!swaggerUiConfigParameters.isValidUrl(swaggerUrl.getUrl()))
-						swaggerUrl.setUrl(buildUrlWithContextPath(swaggerUrl.getUrl()));
-					swaggerUiConfigParameters.getUrls().add(swaggerUrl);
-				});
+				swaggerUiConfig.cloneUrls()
+						.stream()
+						.filter(swaggerUrl -> !swaggerUiConfigParameters.isValidUrl(swaggerUrl.getUrl()))
+						.forEach(swaggerUrl -> {
+							final var url = buildUrlWithContextPath(swaggerUrl.getUrl());
+							if (!Objects.equals(url, swaggerUrl.getUrl())) {
+								swaggerUiConfigParameters.getUrls()
+										.stream()
+										.filter(swaggerUrl::equals)
+										.forEach(subUrl -> subUrl.setUrl(url));
+							}
+						});
 			}
 		}
 		calculateOauth2RedirectUrl(uriComponentsBuilder);

springdoc-openapi-starter-webmvc-ui/src/test/java/test/org/springdoc/ui/app8/SpringDocApp8MultipleUrlsSeveralParallelRequestsTest.java

@@ -0,0 +1,90 @@
+/*
+ *
+ *  * Copyright 2019-2020 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 test.org.springdoc.ui.app8;
+
+import org.junit.jupiter.api.Test;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.test.context.TestPropertySource;
+import test.org.springdoc.ui.AbstractSpringDocTest;
+
+import java.util.concurrent.CompletableFuture;
+import java.util.stream.Stream;
+
+import static java.util.concurrent.CompletableFuture.allOf;
+import static java.util.concurrent.CompletableFuture.runAsync;
+import static org.hamcrest.CoreMatchers.equalTo;
+import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
+import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.jsonPath;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;
+
+/**
+ * The test to make sure no exceptions are thrown when several parallel requests
+ * are sent to get Swagger config.
+ *
+ * @author Dmitry Lebedko ([email protected])
+ */
+@TestPropertySource(properties = {
+		"spring.mvc.servlet.path=/servlet-path",
+		"springdoc.swagger-ui.urls[0].name=first-user-list",
+		"springdoc.swagger-ui.urls[0].url=/api-docs.yaml",
+		"springdoc.swagger-ui.urls[1].name=second-user-list",
+		"springdoc.swagger-ui.urls[1].url=/api-docs.yaml",
+		"springdoc.swagger-ui.urls[2].name=third-user-list",
+		"springdoc.swagger-ui.urls[2].url=/api-docs.yaml"
+})
+public class SpringDocApp8MultipleUrlsSeveralParallelRequestsTest extends AbstractSpringDocTest {
+
+	private static final int PARALLEL_REQUEST_NUMBER = 100;
+
+	/**
+	 * Sends {@link SpringDocApp8MultipleUrlsSeveralParallelRequestsTest#PARALLEL_REQUEST_NUMBER} requests
+	 * simultaneously to make sure no exceptions are thrown when getting Swagger config.
+	 */
+	@Test
+	public void swagger_config_for_multiple_groups_and_many_parallel_requests() {
+		assertDoesNotThrow(() -> {
+			allOf(Stream.generate(() -> runAsync(() -> {
+						try {
+							mockMvc.perform(get("/v3/api-docs/swagger-config"))
+									.andExpect(status().isOk())
+									.andExpect(jsonPath("configUrl", equalTo("/servlet-path/v3/api-docs/swagger-config")))
+										.andExpect(jsonPath("url").doesNotExist())
+									.andExpect(jsonPath("urls.length()", equalTo(3)))
+									.andExpect(jsonPath("urls[0].url", equalTo("/servlet-path/api-docs.yaml")))
+									.andExpect(jsonPath("urls[0].name", equalTo("first-user-list")))
+									.andExpect(jsonPath("urls[1].url", equalTo("/servlet-path/api-docs.yaml")))
+									.andExpect(jsonPath("urls[1].name", equalTo("second-user-list")))
+									.andExpect(jsonPath("urls[2].url", equalTo("/servlet-path/api-docs.yaml")))
+									.andExpect(jsonPath("urls[2].name", equalTo("third-user-list")));
+						} catch (Exception e) {
+							throw new RuntimeException(e);
+						}
+					}))
+					.limit(PARALLEL_REQUEST_NUMBER)
+					.toArray(CompletableFuture[]::new))
+					.join();
+		}, "Swagger config is supposed to be delivered successfully " +
+				"no matter how many parallel requests are sent");
+	}
+
+	@SpringBootApplication
+	static class SpringDocTestApp {}
+
+}