From 3768d221fcb4b5507cccf632fd328ee096794746 Mon Sep 17 00:00:00 2001
From: Marcin Grzejszczak <marcin.grzejszczak@gmail.com>
Date: Thu, 6 Aug 2020 19:09:53 +0200
Subject: [PATCH] For Gateway will set reactor instrumentation to manual; fixes
 gh-1710

---
 .../TraceGatewayEnvironmentPostProcessor.java | 105 ++++++++++++++++++
 .../main/resources/META-INF/spring.factories  |   3 +-
 2 files changed, 107 insertions(+), 1 deletion(-)
 create mode 100644 spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/instrument/web/client/TraceGatewayEnvironmentPostProcessor.java

diff --git a/spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/instrument/web/client/TraceGatewayEnvironmentPostProcessor.java b/spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/instrument/web/client/TraceGatewayEnvironmentPostProcessor.java
new file mode 100644
index 000000000..e73d7b645
--- /dev/null
+++ b/spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/instrument/web/client/TraceGatewayEnvironmentPostProcessor.java
@@ -0,0 +1,105 @@
+/*
+ * Copyright 2013-2019 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.sleuth.instrument.web.client;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.env.EnvironmentPostProcessor;
+import org.springframework.core.env.ConfigurableEnvironment;
+import org.springframework.core.env.MapPropertySource;
+import org.springframework.core.env.MutablePropertySources;
+import org.springframework.core.env.PropertySource;
+import org.springframework.util.ClassUtils;
+import org.springframework.util.StringUtils;
+
+/**
+ * Adds default properties for a gateway application.
+ *
+ * @author Marcin Grzejszczak
+ * @since 3.0.0
+ */
+class TraceGatewayEnvironmentPostProcessor implements EnvironmentPostProcessor {
+
+	private static final Log log = LogFactory.getLog(TraceGatewayEnvironmentPostProcessor.class);
+
+	private static final String PROPERTY_SOURCE_NAME = "defaultProperties";
+
+	@Override
+	public void postProcessEnvironment(ConfigurableEnvironment environment,
+			SpringApplication application) {
+		Map<String, Object> map = new HashMap<>();
+		if (sleuthEnabled(environment) && isGatewayOnTheClasspath()) {
+			String instrumentationType = environment
+					.getProperty("spring.sleuth.reactor.instrumentation-type");
+			if (log.isDebugEnabled()) {
+				log.debug("Found the following instrumentation type [" + instrumentationType + "]");
+			}
+			if (StringUtils.isEmpty(instrumentationType)) {
+				instrumentationType = "manual";
+				if (log.isDebugEnabled()) {
+					log.debug("No instrumentation type passed, will force it to [" + instrumentationType + "]");
+				}
+			}
+			map.put("spring.sleuth.reactor.instrumentation-type", instrumentationType);
+		}
+		addOrReplace(environment.getPropertySources(), map);
+	}
+
+	private boolean sleuthEnabled(ConfigurableEnvironment environment) {
+		return Boolean
+				.parseBoolean(environment.getProperty("spring.sleuth.enabled", "true"));
+	}
+
+	private boolean isGatewayOnTheClasspath() {
+		try {
+			ClassUtils.forName("org.springframework.cloud.gateway.filter.GatewayFilter",
+					null);
+			return true;
+		}
+		catch (ClassNotFoundException e) {
+			return false;
+		}
+	}
+
+	private void addOrReplace(MutablePropertySources propertySources,
+			Map<String, Object> map) {
+		MapPropertySource target = null;
+		if (propertySources.contains(PROPERTY_SOURCE_NAME)) {
+			PropertySource<?> source = propertySources.get(PROPERTY_SOURCE_NAME);
+			if (source instanceof MapPropertySource) {
+				target = (MapPropertySource) source;
+				for (String key : map.keySet()) {
+					if (!target.containsProperty(key)) {
+						target.getSource().put(key, map.get(key));
+					}
+				}
+			}
+		}
+		if (target == null) {
+			target = new MapPropertySource(PROPERTY_SOURCE_NAME, map);
+		}
+		if (!propertySources.contains(PROPERTY_SOURCE_NAME)) {
+			propertySources.addLast(target);
+		}
+	}
+
+}
diff --git a/spring-cloud-sleuth-core/src/main/resources/META-INF/spring.factories b/spring-cloud-sleuth-core/src/main/resources/META-INF/spring.factories
index c38ab6698..19451fb5e 100644
--- a/spring-cloud-sleuth-core/src/main/resources/META-INF/spring.factories
+++ b/spring-cloud-sleuth-core/src/main/resources/META-INF/spring.factories
@@ -30,4 +30,5 @@ org.springframework.cloud.sleuth.instrument.mongodb.TraceMongoDbAutoConfiguratio
 
 # Environment Post Processor
 org.springframework.boot.env.EnvironmentPostProcessor=\
-org.springframework.cloud.sleuth.autoconfig.TraceEnvironmentPostProcessor
+org.springframework.cloud.sleuth.autoconfig.TraceEnvironmentPostProcessor,\
+org.springframework.cloud.sleuth.instrument.web.client.TraceGatewayEnvironmentPostProcessor