SearchSlowLog uses a non thread-safe object to escape json (#48363)

This commit fixes the usage of JsonStringEncoder#quoteAsUTF8 in the SearchSlowLog.
JsonStringEncoder#getInstance should always be called to get a thread local object
but this assumption was broken by #44642. This means that any slow log can throw
an AIOOBE since it uses the same byte array concurrently.

Closes #48358

server/src/main/java/org/elasticsearch/common/logging/ESLogMessage.java

@@ -18,13 +18,11 @@
  */
 package org.elasticsearch.common.logging;
 
-import com.fasterxml.jackson.core.io.JsonStringEncoder;
 import org.apache.logging.log4j.message.MapMessage;
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.apache.logging.log4j.util.Chars;
 import org.apache.logging.log4j.util.StringBuilders;
 
-import java.nio.charset.Charset;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.LinkedHashMap;
@@ -37,8 +35,6 @@
  * A base class for custom log4j logger messages. Carries additional fields which will populate JSON fields in logs.
  */
 public class ESLogMessage extends MapMessage<ESLogMessage, Object> {
-    private static final JsonStringEncoder JSON_STRING_ENCODER = JsonStringEncoder.getInstance();
-
     private final String messagePattern;
     private final List<Object> arguments = new ArrayList<>();
 
@@ -106,9 +102,4 @@ public static String asJsonArray(Stream<String> stream) {
             .map(ESLogMessage::inQuotes)
             .collect(Collectors.joining(", ")) + "]";
     }
-
-    public static String escapeJson(String text) {
-        byte[] sourceEscaped = JSON_STRING_ENCODER.quoteAsUTF8(text);
-        return new String(sourceEscaped, Charset.defaultCharset());
-    }
 }

server/src/main/java/org/elasticsearch/index/SearchSlowLog.java

@@ -19,6 +19,7 @@
 
 package org.elasticsearch.index;
 
+import com.fasterxml.jackson.core.io.JsonStringEncoder;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.elasticsearch.common.Strings;
@@ -32,13 +33,16 @@
 import org.elasticsearch.search.internal.SearchContext;
 import org.elasticsearch.tasks.Task;
 
+import java.nio.charset.Charset;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
 import java.util.stream.Stream;
 
 public final class SearchSlowLog implements SearchOperationListener {
+    private static final Charset UTF_8 = Charset.forName("UTF-8");
+
     private long queryWarnThreshold;
     private long queryInfoThreshold;
     private long queryDebugThreshold;
@@ -169,13 +173,13 @@ private static Map<String, Object> prepareMap(SearchContext context, long tookIn
             } else {
                 messageFields.put("total_hits", "-1");
             }
-            messageFields.put("stats", ESLogMessage.escapeJson(ESLogMessage.asJsonArray(
+            messageFields.put("stats", escapeJson(ESLogMessage.asJsonArray(
                 context.groupStats() != null ? context.groupStats().stream() : Stream.empty())));
             messageFields.put("search_type", context.searchType());
             messageFields.put("total_shards", context.numberOfShards());
 
             if (context.request().source() != null) {
-                String source = ESLogMessage.escapeJson(context.request().source().toString(FORMAT_PARAMS));
+                String source = escapeJson(context.request().source().toString(FORMAT_PARAMS));
 
                 messageFields.put("source", source);
             } else {
@@ -221,6 +225,11 @@ private static String message(SearchContext context, long tookInNanos) {
             }
             return sb.toString();
         }
+
+        private static String escapeJson(String text) {
+            byte[] sourceEscaped = JsonStringEncoder.getInstance().quoteAsUTF8(text);
+            return new String(sourceEscaped, UTF_8);
+        }
     }
 
     private void setQueryWarnThreshold(TimeValue warnThreshold) {