Adding ThreadLocalAccessor for TwContext

CHANGELOG.md

@@ -5,6 +5,11 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/), and this project adheres
 to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [2.1.0] - 2024-11-08
+
+### Changed
+* Added ThreadLocalAccessor for TwContext so it can be available for libraries using micrometer context propagation API
+
 ## [2.0.1] - 2024-07-16
 
 ### Changed

build.libraries.gradle

@@ -7,6 +7,7 @@ ext {
             guava                           : 'com.google.guava:guava:33.0.0-jre',
             springBootDependencies          : "org.springframework.boot:spring-boot-dependencies:${springBootVersion}",
             twBaseUtils                     : "com.transferwise.common:tw-base-utils:1.12.3",
+            micrometerContextPropagation    : "io.micrometer:context-propagation:1.1.2",
 
             // versions managed by spring-boot-dependencies platform
             assertjCore                     : 'org.assertj:assertj-core',

gradle.properties

@@ -1 +1,2 @@
-version=2.0.1
+version=2.1.0
+

tw-context/build.gradle

@@ -10,6 +10,7 @@ dependencies {
     implementation libraries.slf4jApi
     implementation libraries.guava
     implementation libraries.twBaseUtils
+    implementation libraries.micrometerContextPropagation
 
     api libraries.micrometerCore
 }

tw-context/src/main/java/com/transferwise/common/context/TwContext.java

@@ -3,6 +3,7 @@
 import com.google.common.annotations.VisibleForTesting;
 import com.google.common.util.concurrent.RateLimiter;
 import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
+import io.micrometer.context.ContextRegistry;
 import java.util.HashMap;
 import java.util.Iterator;
 import java.util.List;
@@ -35,9 +36,14 @@ public class TwContext {
   private static final ThreadLocal<Optional<TwContext>> contextTl = new ThreadLocal<>();
   private static final List<TwContextExecutionInterceptor> interceptors = new CopyOnWriteArrayList<>();
   private static final List<TwContextAttributePutListener> attributePutListeners = new CopyOnWriteArrayList<>();
-  private static final TwContext ROOT_CONTEXT = new TwContext(null, true);
   private static final RateLimiter throwableLoggingRateLimiter = RateLimiter.create(2);
 
+  static final TwContext ROOT_CONTEXT = new TwContext(null, true);
+
+  static {
+    ContextRegistry.getInstance().registerThreadLocalAccessor(new TwContextThreadLocalAccessor());
+  }
+
   public static TwContext current() {
     Optional<TwContext> twContext = contextTl.get();
     return twContext == null || !twContext.isPresent() ? ROOT_CONTEXT : twContext.get();

tw-context/src/main/java/com/transferwise/common/context/TwContextThreadLocalAccessor.java

@@ -0,0 +1,28 @@
+package com.transferwise.common.context;
+
+import static com.transferwise.common.context.UnitOfWork.TW_CONTEXT_KEY;
+
+import io.micrometer.context.ThreadLocalAccessor;
+
+public class TwContextThreadLocalAccessor implements ThreadLocalAccessor<TwContext> {
+
+  @Override
+  public Object key() {
+    return TW_CONTEXT_KEY;
+  }
+
+  @Override
+  public TwContext getValue() {
+    return TwContext.current();
+  }
+
+  @Override
+  public void setValue(TwContext context) {
+    context.attach();
+  }
+
+  @Override
+  public void reset() {
+    TwContext.ROOT_CONTEXT.attach();
+  }
+}