Synchronize SPI decorator loading

* eagerly load decorators obtained via SPI to avoid exceptions in high-concurrency setups * instances of `ServiceLoader` are not thread-safe, iterating on the `Iterable` may yield exceptions if done concurrently * eager loading prevents any reloading functionality of `ServiceLoader` to work (acceptable)
zalando · Aug 14, 2023 · b9eb66a · b9eb66a
1 parent 4350726
commit b9eb66a
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Showing 4 changed files with 34 additions and 4 deletions.
diff --git a/...cing-jdbc/src/main/java/org/zalando/opentracing/jdbc/span/ServiceLoaderSpanDecorator.java b/...cing-jdbc/src/main/java/org/zalando/opentracing/jdbc/span/ServiceLoaderSpanDecorator.java
@@ -2,9 +2,12 @@
 
 import org.apiguardian.api.API;
 
+import java.util.List;
 import java.util.ServiceLoader;
 
 import static java.util.ServiceLoader.load;
+import static java.util.stream.Collectors.toList;
+import static java.util.stream.StreamSupport.stream;
 import static org.apiguardian.api.API.Status.EXPERIMENTAL;
 import static org.zalando.opentracing.jdbc.span.SpanDecorator.composite;
 
@@ -15,7 +18,11 @@
 public final class ServiceLoaderSpanDecorator extends ForwardingSpanDecorator {
 
     public ServiceLoaderSpanDecorator() {
-        super(composite(load(SpanDecorator.class)));
+        super(composite(loadDecorators()));
+    }
+
+    private static synchronized List<SpanDecorator> loadDecorators() {
+        return stream(load(SpanDecorator.class).spliterator(), false).collect(toList());
     }
 
 }
diff --git a/...n/src/main/java/org/zalando/opentracing/servlet/extension/ServiceLoaderSpanDecorator.java b/...n/src/main/java/org/zalando/opentracing/servlet/extension/ServiceLoaderSpanDecorator.java
@@ -3,9 +3,12 @@
 import io.opentracing.contrib.web.servlet.filter.ServletFilterSpanDecorator;
 import org.apiguardian.api.API;
 
+import java.util.List;
 import java.util.ServiceLoader;
 
 import static java.util.ServiceLoader.load;
+import static java.util.stream.Collectors.toList;
+import static java.util.stream.StreamSupport.stream;
 import static org.apiguardian.api.API.Status.EXPERIMENTAL;
 
 /**
@@ -15,7 +18,11 @@
 public final class ServiceLoaderSpanDecorator extends ForwardingSpanDecorator {
 
     public ServiceLoaderSpanDecorator() {
-        super(CompositeSpanDecorator.composite(load(ServletFilterSpanDecorator.class)));
+        super(CompositeSpanDecorator.composite(loadDecorators()));
+    }
+
+    private static synchronized List<ServletFilterSpanDecorator> loadDecorators() {
+        return stream(load(ServletFilterSpanDecorator.class).spliterator(), false).collect(toList());
     }
 
 }
diff --git a/...rc/main/java/org/zalando/opentracing/spring/web/extension/ServiceLoaderSpanDecorator.java b/...rc/main/java/org/zalando/opentracing/spring/web/extension/ServiceLoaderSpanDecorator.java
@@ -3,9 +3,12 @@
 import io.opentracing.contrib.spring.web.interceptor.HandlerInterceptorSpanDecorator;
 import org.apiguardian.api.API;
 
+import java.util.List;
 import java.util.ServiceLoader;
 
 import static java.util.ServiceLoader.load;
+import static java.util.stream.Collectors.toList;
+import static java.util.stream.StreamSupport.stream;
 import static org.apiguardian.api.API.Status.EXPERIMENTAL;
 import static org.zalando.opentracing.spring.web.extension.CompositeSpanDecorator.composite;
 
@@ -17,6 +20,11 @@ public final class ServiceLoaderSpanDecorator
         extends ForwardingSpanDecorator {
 
     public ServiceLoaderSpanDecorator() {
-        super(composite(load(HandlerInterceptorSpanDecorator.class)));
+        super(composite(loadDecorators()));
     }
+
+    private static synchronized List<HandlerInterceptorSpanDecorator> loadDecorators() {
+        return stream(load(HandlerInterceptorSpanDecorator.class).spliterator(), false).collect(toList());
+    }
+
 }
diff --git a/...ain/java/org/zalando/opentracing/spring/webflux/extension/ServiceLoaderSpanDecorator.java b/...ain/java/org/zalando/opentracing/spring/webflux/extension/ServiceLoaderSpanDecorator.java
@@ -3,9 +3,12 @@
 import io.opentracing.contrib.spring.web.webfilter.WebFluxSpanDecorator;
 import org.apiguardian.api.API;
 
+import java.util.List;
 import java.util.ServiceLoader;
 
 import static java.util.ServiceLoader.load;
+import static java.util.stream.Collectors.toList;
+import static java.util.stream.StreamSupport.stream;
 import static org.apiguardian.api.API.Status.EXPERIMENTAL;
 import static org.zalando.opentracing.spring.webflux.extension.CompositeSpanDecorator.composite;
 
@@ -17,6 +20,11 @@ public final class ServiceLoaderSpanDecorator
         extends ForwardingSpanDecorator {
 
     public ServiceLoaderSpanDecorator() {
-        super(composite(load(WebFluxSpanDecorator.class)));
+        super(composite(loadDecorators()));
     }
+
+    private static synchronized List<WebFluxSpanDecorator> loadDecorators() {
+        return stream(load(WebFluxSpanDecorator.class).spliterator(), false).collect(toList());
+    }
+
 }