apache · ppkarwasz · Aug 26, 2024 · Aug 16, 2024
diff --git a/log4j-core/src/main/java/org/apache/logging/log4j/core/ContextDataInjector.java b/log4j-core/src/main/java/org/apache/logging/log4j/core/ContextDataInjector.java
@@ -105,6 +105,19 @@ public interface ContextDataInjector {
      * the implementation of this method. It is not safe to pass the returned object to another thread.
      * </p>
      * @return a {@code ReadOnlyStringMap} object reflecting the current state of the context, may not return {@code null}
+     * @deprecated Since 2.24.0 use {@link #getValue} instead.
      */
+    @Deprecated
     ReadOnlyStringMap rawContextData();
+
+    /**
+     * Retrieves a single context data value.
+     *
+     * @param key The context data key of the value to retrieve.
+     * @return A context data value.
+     * @since 2.24.0
+     */
+    default Object getValue(final String key) {
+        return rawContextData().getValue(key);
+    }
 }
diff --git a/log4j-core/src/main/java/org/apache/logging/log4j/core/filter/DynamicThresholdFilter.java b/log4j-core/src/main/java/org/apache/logging/log4j/core/filter/DynamicThresholdFilter.java
@@ -36,7 +36,6 @@
 import org.apache.logging.log4j.core.util.KeyValuePair;
 import org.apache.logging.log4j.message.Message;
 import org.apache.logging.log4j.util.PerformanceSensitive;
-import org.apache.logging.log4j.util.ReadOnlyStringMap;
 import org.apache.logging.log4j.util.StringMap;
 
 /**
@@ -125,10 +124,9 @@ public boolean equals(final Object obj) {
         return true;
     }
 
-    private Result filter(final Level level, final ReadOnlyStringMap contextMap) {
-        final String value = contextMap.getValue(key);
+    private Result filter(final Level level, final Object value) {
         if (value != null) {
-            Level ctxLevel = levelMap.get(value);
+            Level ctxLevel = levelMap.get(Objects.toString(value, null));
             if (ctxLevel == null) {
                 ctxLevel = defaultThreshold;
             }
@@ -139,35 +137,31 @@ private Result filter(final Level level, final ReadOnlyStringMap contextMap) {
 
     @Override
     public Result filter(final LogEvent event) {
-        return filter(event.getLevel(), event.getContextData());
+        return filter(event.getLevel(), event.getContextData().getValue(key));
     }
 
     @Override
     public Result filter(
             final Logger logger, final Level level, final Marker marker, final Message msg, final Throwable t) {
-        return filter(level, currentContextData());
+        return filter(level, injector.getValue(key));
     }
 
     @Override
     public Result filter(
             final Logger logger, final Level level, final Marker marker, final Object msg, final Throwable t) {
-        return filter(level, currentContextData());
+        return filter(level, injector.getValue(key));
     }
 
     @Override
     public Result filter(
             final Logger logger, final Level level, final Marker marker, final String msg, final Object... params) {
-        return filter(level, currentContextData());
-    }
-
-    private ReadOnlyStringMap currentContextData() {
-        return injector.rawContextData();
+        return filter(level, injector.getValue(key));
     }
 
     @Override
     public Result filter(
             final Logger logger, final Level level, final Marker marker, final String msg, final Object p0) {
-        return filter(level, currentContextData());
+        return filter(level, injector.getValue(key));
     }
 
     @Override
@@ -178,7 +172,7 @@ public Result filter(
             final String msg,
             final Object p0,
             final Object p1) {
-        return filter(level, currentContextData());
+        return filter(level, injector.getValue(key));
     }
 
     @Override
@@ -190,7 +184,7 @@ public Result filter(
             final Object p0,
             final Object p1,
             final Object p2) {
-        return filter(level, currentContextData());
+        return filter(level, injector.getValue(key));
     }
 
     @Override
@@ -203,7 +197,7 @@ public Result filter(
             final Object p1,
             final Object p2,
             final Object p3) {
-        return filter(level, currentContextData());
+        return filter(level, injector.getValue(key));
     }
 
     @Override
@@ -217,7 +211,7 @@ public Result filter(
             final Object p2,
             final Object p3,
             final Object p4) {
-        return filter(level, currentContextData());
+        return filter(level, injector.getValue(key));
     }
 
     @Override
@@ -232,7 +226,7 @@ public Result filter(
             final Object p3,
             final Object p4,
             final Object p5) {
-        return filter(level, currentContextData());
+        return filter(level, injector.getValue(key));
     }
 
     @Override
@@ -248,7 +242,7 @@ public Result filter(
             final Object p4,
             final Object p5,
             final Object p6) {
-        return filter(level, currentContextData());
+        return filter(level, injector.getValue(key));
     }
 
     @Override
@@ -265,7 +259,7 @@ public Result filter(
             final Object p5,
             final Object p6,
             final Object p7) {
-        return filter(level, currentContextData());
+        return filter(level, injector.getValue(key));
     }
 
     @Override
@@ -283,7 +277,7 @@ public Result filter(
             final Object p6,
             final Object p7,
             final Object p8) {
-        return filter(level, currentContextData());
+        return filter(level, injector.getValue(key));
     }
 
     @Override
@@ -302,7 +296,7 @@ public Result filter(
             final Object p7,
             final Object p8,
             final Object p9) {
-        return filter(level, currentContextData());
+        return filter(level, injector.getValue(key));
     }
 
     public String getKey() {

diff --git a/log4j-core/src/main/java/org/apache/logging/log4j/core/filter/ThreadContextMapFilter.java b/log4j-core/src/main/java/org/apache/logging/log4j/core/filter/ThreadContextMapFilter.java
@@ -21,6 +21,7 @@
 import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 import org.apache.logging.log4j.Level;
 import org.apache.logging.log4j.Marker;
 import org.apache.logging.log4j.core.ContextDataInjector;
@@ -39,7 +40,6 @@
 import org.apache.logging.log4j.message.Message;
 import org.apache.logging.log4j.util.IndexedReadOnlyStringMap;
 import org.apache.logging.log4j.util.PerformanceSensitive;
-import org.apache.logging.log4j.util.ReadOnlyStringMap;
 import org.apache.logging.log4j.util.StringMap;
 
 /**
@@ -109,26 +109,22 @@ public Result filter(
     private Result filter() {
         boolean match = false;
         if (useMap) {
-            ReadOnlyStringMap currentContextData = null;
             final IndexedReadOnlyStringMap map = getStringMap();
             for (int i = 0; i < map.size(); i++) {
-                if (currentContextData == null) {
-                    currentContextData = currentContextData();
-                }
-                final String toMatch = currentContextData.getValue(map.getKeyAt(i));
-                match = toMatch != null && ((List<String>) map.getValueAt(i)).contains(toMatch);
+                final String toMatch = getContextValue(map.getKeyAt(i));
+                match = toMatch != null && map.<List<String>>getValueAt(i).contains(toMatch);
                 if ((!isAnd() && match) || (isAnd() && !match)) {
                     break;
                 }
             }
         } else {
-            match = value.equals(currentContextData().getValue(key));
+            match = value.equals(getContextValue(key));
         }
         return match ? onMatch : onMismatch;
     }
 
-    private ReadOnlyStringMap currentContextData() {
-        return injector.rawContextData();
+    private String getContextValue(final String key) {
+        return Objects.toString(injector.getValue(key), null);
     }
 
     @Override

diff --git a/log4j-core/src/main/java/org/apache/logging/log4j/core/impl/ThreadContextDataInjector.java b/log4j-core/src/main/java/org/apache/logging/log4j/core/impl/ThreadContextDataInjector.java
@@ -87,19 +87,33 @@ private static List<ContextDataProvider> getServiceProviders() {
         return Collections.unmodifiableList(providers);
     }
 
+    private abstract static class AbstractContextDataInjector implements ContextDataInjector {
+
+        final List<ContextDataProvider> providers;
+
+        AbstractContextDataInjector() {
+            this.providers = getProviders();
+        }
+
+        @Override
+        public Object getValue(String key) {
+            for (final ContextDataProvider provider : providers) {
+                final Object value = provider.getValue(key);
+                if (value != null) {
+                    return value;
+                }
+            }
+            return null;
+        }
+    }
+
     /**
      * Default {@code ContextDataInjector} for the legacy {@code Map<String, String>}-based ThreadContext (which is
      * also the ThreadContext implementation used for web applications).
      * <p>
      * This injector always puts key-value pairs into the specified reusable StringMap.
      */
-    public static class ForDefaultThreadContextMap implements ContextDataInjector {
-
-        private final List<ContextDataProvider> providers;
-
-        public ForDefaultThreadContextMap() {
-            providers = getProviders();
-        }
+    public static class ForDefaultThreadContextMap extends AbstractContextDataInjector {
 
         /**
          * Puts key-value pairs from both the specified list of properties as well as the thread context into the
@@ -171,12 +185,7 @@ public ReadOnlyStringMap rawContextData() {
      * <p>
      * This injector always puts key-value pairs into the specified reusable StringMap.
      */
-    public static class ForGarbageFreeThreadContextMap implements ContextDataInjector {
-        private final List<ContextDataProvider> providers;
-
-        public ForGarbageFreeThreadContextMap() {
-            this.providers = getProviders();
-        }
+    public static class ForGarbageFreeThreadContextMap extends AbstractContextDataInjector {
 
         /**
          * Puts key-value pairs from both the specified list of properties as well as the thread context into the
@@ -212,12 +221,8 @@ public ReadOnlyStringMap rawContextData() {
      * structure. Otherwise the configuration properties are combined with the thread context key-value pairs into the
      * specified reusable StringMap.
      */
-    public static class ForCopyOnWriteThreadContextMap implements ContextDataInjector {
-        private final List<ContextDataProvider> providers;
+    public static class ForCopyOnWriteThreadContextMap extends AbstractContextDataInjector {
 
-        public ForCopyOnWriteThreadContextMap() {
-            this.providers = getProviders();
-        }
         /**
          * If there are no configuration properties, this injector will return the thread context's internal data
          * structure. Otherwise the configuration properties are combined with the thread context key-value pairs into the

diff --git a/log4j-core/src/main/java/org/apache/logging/log4j/core/impl/package-info.java b/log4j-core/src/main/java/org/apache/logging/log4j/core/impl/package-info.java
@@ -18,7 +18,7 @@
  * Log4j 2 private implementation classes.
  */
 @Export
-@Version("2.23.0")
+@Version("2.24.0")
 package org.apache.logging.log4j.core.impl;
 
 import org.osgi.annotation.bundle.Export;

diff --git a/log4j-core/src/main/java/org/apache/logging/log4j/core/lookup/ContextMapLookup.java b/log4j-core/src/main/java/org/apache/logging/log4j/core/lookup/ContextMapLookup.java
@@ -16,12 +16,12 @@
  */
 package org.apache.logging.log4j.core.lookup;
 
+import java.util.Objects;
 import org.apache.logging.log4j.ThreadContext;
 import org.apache.logging.log4j.core.ContextDataInjector;
 import org.apache.logging.log4j.core.LogEvent;
 import org.apache.logging.log4j.core.config.plugins.Plugin;
 import org.apache.logging.log4j.core.impl.ContextDataInjectorFactory;
-import org.apache.logging.log4j.util.ReadOnlyStringMap;
 
 /**
  * Looks up keys from the context. By default this is the {@link ThreadContext}, but users may
@@ -40,11 +40,7 @@ public class ContextMapLookup implements StrLookup {
      */
     @Override
     public String lookup(final String key) {
-        return currentContextData().getValue(key);
-    }
-
-    private ReadOnlyStringMap currentContextData() {
-        return injector.rawContextData();
+        return Objects.toString(injector.getValue(key), null);
     }
 
     /**

diff --git a/log4j-core/src/main/java/org/apache/logging/log4j/core/util/ContextDataProvider.java b/log4j-core/src/main/java/org/apache/logging/log4j/core/util/ContextDataProvider.java
@@ -46,4 +46,17 @@ public interface ContextDataProvider {
     default StringMap supplyStringMap() {
         return new JdkMapAdapterStringMap(supplyContextData(), true);
     }
+
+    /**
+     * Retrieves a single context data value.
+     * <p>
+     *     This method avoids the overhead of copying the entire context data, when only a single value is needed.
+     * </p>
+     * @param key The context data key of the value to retrieve.
+     * @return A context data value.
+     * @since 2.24.0
+     */
+    default Object getValue(final String key) {
+        return supplyContextData().get(key);
+    }
 }
diff --git a/log4j-core/src/main/java/org/apache/logging/log4j/core/util/package-info.java b/log4j-core/src/main/java/org/apache/logging/log4j/core/util/package-info.java
@@ -18,7 +18,7 @@
  * Log4j 2 helper classes.
  */
 @Export
-@Version("2.20.2")
+@Version("2.24.0")
 package org.apache.logging.log4j.core.util;
 
 import org.osgi.annotation.bundle.Export;

diff --git a/src/changelog/.2.x.x/2331_custom_context_data_in_lookup.xml b/src/changelog/.2.x.x/2331_custom_context_data_in_lookup.xml
@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<entry xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+       xmlns="https://logging.apache.org/xml/ns"
+       xsi:schemaLocation="https://logging.apache.org/xml/ns https://logging.apache.org/xml/ns/log4j-changelog-0.xsd"
+       type="fixed">
+  <issue id="2331" link="https://github.com/apache/logging-log4j2/issues/2331"/>
+  <description format="asciidoc">Fix custom thread-context data provider handling in lookups and filters.</description>
+</entry>