From dd02c9db603bb23880da6b466dea363b35f8066b Mon Sep 17 00:00:00 2001
From: Marcin Grzejszczak <mgrzejszczak@vmware.com>
Date: Wed, 13 Jul 2022 08:38:48 +0200
Subject: [PATCH] Makes Zipkin ReporterMetrics lazy; fixes gh-2185

---
 .../zipkin2/ZipkinAutoConfiguration.java      | 64 ++++++++++++++++++-
 1 file changed, 62 insertions(+), 2 deletions(-)

diff --git a/spring-cloud-sleuth-autoconfigure/src/main/java/org/springframework/cloud/sleuth/autoconfig/zipkin2/ZipkinAutoConfiguration.java b/spring-cloud-sleuth-autoconfigure/src/main/java/org/springframework/cloud/sleuth/autoconfig/zipkin2/ZipkinAutoConfiguration.java
index 95f056925..fa8e70f73 100644
--- a/spring-cloud-sleuth-autoconfigure/src/main/java/org/springframework/cloud/sleuth/autoconfig/zipkin2/ZipkinAutoConfiguration.java
+++ b/spring-cloud-sleuth-autoconfigure/src/main/java/org/springframework/cloud/sleuth/autoconfig/zipkin2/ZipkinAutoConfiguration.java
@@ -36,6 +36,7 @@ import zipkin2.reporter.ReporterMetrics;
 import zipkin2.reporter.Sender;
 import zipkin2.reporter.metrics.micrometer.MicrometerReporterMetrics;
 
+import org.springframework.beans.factory.ObjectProvider;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.beans.factory.annotation.Qualifier;
 import org.springframework.boot.autoconfigure.AutoConfigureAfter;
@@ -255,8 +256,8 @@ public class ZipkinAutoConfiguration {
 			@Bean
 			@ConditionalOnBean(MeterRegistry.class)
 			@ConditionalOnClass(name = "zipkin2.reporter.metrics.micrometer.MicrometerReporterMetrics")
-			ReporterMetrics sleuthMicrometerReporterMetrics(MeterRegistry meterRegistry) {
-				return MicrometerReporterMetrics.create(meterRegistry);
+			ReporterMetrics sleuthMicrometerReporterMetrics(ObjectProvider<MeterRegistry> meterRegistry) {
+				return new LazyMicrometerReporterMetrics(meterRegistry);
 			}
 
 			@Bean
@@ -265,6 +266,65 @@ public class ZipkinAutoConfiguration {
 				return new InMemoryReporterMetrics();
 			}
 
+			static class LazyMicrometerReporterMetrics implements ReporterMetrics {
+
+				private final ObjectProvider<MeterRegistry> objectProvider;
+
+				private ReporterMetrics micrometerReporterMetrics;
+
+				LazyMicrometerReporterMetrics(ObjectProvider<MeterRegistry> objectProvider) {
+					this.objectProvider = objectProvider;
+				}
+
+				private ReporterMetrics reporterMetrics() {
+					if (this.micrometerReporterMetrics == null) {
+						this.micrometerReporterMetrics = MicrometerReporterMetrics.create(objectProvider.getObject());
+					}
+					return this.micrometerReporterMetrics;
+				}
+
+				@Override
+				public void incrementMessages() {
+					reporterMetrics().incrementMessages();
+				}
+
+				@Override
+				public void incrementMessagesDropped(Throwable throwable) {
+					reporterMetrics().incrementMessagesDropped(throwable);
+				}
+
+				@Override
+				public void incrementSpans(int i) {
+					reporterMetrics().incrementSpans(i);
+				}
+
+				@Override
+				public void incrementSpanBytes(int i) {
+					reporterMetrics().incrementSpanBytes(i);
+				}
+
+				@Override
+				public void incrementMessageBytes(int i) {
+					reporterMetrics().incrementMessageBytes(i);
+				}
+
+				@Override
+				public void incrementSpansDropped(int i) {
+					reporterMetrics().incrementSpansDropped(i);
+				}
+
+				@Override
+				public void updateQueuedSpans(int i) {
+					reporterMetrics().updateQueuedSpans(i);
+				}
+
+				@Override
+				public void updateQueuedBytes(int i) {
+					reporterMetrics().updateQueuedBytes(i);
+				}
+
+			}
+
 		}
 
 	}