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

@@ -19,11 +19,9 @@
 
 package org.elasticsearch.common.logging;
 
-import com.fasterxml.jackson.core.io.JsonStringEncoder;
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.elasticsearch.common.SuppressLoggerChecks;
 
-import java.nio.charset.Charset;
 import java.util.Map;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
@@ -32,7 +30,6 @@
  * A base class for custom log4j logger messages. Carries additional fields which will populate JSON fields in logs.
  */
 public abstract class ESLogMessage extends ParameterizedMessage {
-    private static final JsonStringEncoder JSON_STRING_ENCODER = JsonStringEncoder.getInstance();
     private final Map<String, Object> fields;
 
     /**
@@ -45,11 +42,6 @@ public ESLogMessage(Map<String, Object> fields, String messagePattern, Object...
         this.fields = fields;
     }
 
-    public static String escapeJson(String text) {
-        byte[] sourceEscaped = JSON_STRING_ENCODER.quoteAsUTF8(text);
-        return new String(sourceEscaped, Charset.defaultCharset());
-    }
-
     public String getValueFor(String key) {
         Object value = fields.get(key);
         return value != null ? value.toString() : null;

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;
@@ -33,13 +34,16 @@
 import org.elasticsearch.tasks.Task;
 
 import java.util.Arrays;
+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;
@@ -230,6 +234,11 @@ 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) {