Fix search anoymizer only (opensearch-project#4783)

* fix anoymizer for search command

Signed-off-by: xinyual <xinyual@amazon.com>

* pushdown match when only one equal in search command

Signed-off-by: xinyual <xinyual@amazon.com>

* fix regex case

Signed-off-by: xinyual <xinyual@amazon.com>

* fix UT

Signed-off-by: xinyual <xinyual@amazon.com>

* fix UT

Signed-off-by: xinyual <xinyual@amazon.com>

* revert match change

Signed-off-by: xinyual <xinyual@amazon.com>

* fix UT by ignore the expression

Signed-off-by: xinyual <xinyual@amazon.com>

* remove useless change and resolve comment

Signed-off-by: xinyual <xinyual@amazon.com>

* remove useless change and resolve comment

Signed-off-by: xinyual <xinyual@amazon.com>

* add test cases for metadata and timestamp identifier

Signed-off-by: xinyual <xinyual@amazon.com>

* change name

Signed-off-by: xinyual <xinyual@amazon.com>

---------

Signed-off-by: xinyual <xinyual@amazon.com>

Author: xinyual

core/src/main/java/org/opensearch/sql/ast/dsl/AstDSL.java

@@ -113,7 +113,7 @@ public UnresolvedPlan describe(String tableName) {
   }
 
   public static UnresolvedPlan search(UnresolvedPlan input, String queryString) {
-    return new Search(input, queryString);
+    return new Search(input, queryString, null);
   }
 
   public UnresolvedPlan subqueryAlias(UnresolvedPlan child, String alias) {

core/src/main/java/org/opensearch/sql/ast/expression/SearchAnd.java

@@ -27,6 +27,11 @@ public String toQueryString() {
     return left.toQueryString() + " AND " + right.toQueryString();
   }
 
+  @Override
+  public String toAnonymizedString() {
+    return left.toAnonymizedString() + " AND " + right.toAnonymizedString();
+  }
+
   @Override
   public List<? extends UnresolvedExpression> getChild() {
     return Arrays.asList(left, right);

core/src/main/java/org/opensearch/sql/ast/expression/SearchComparison.java

@@ -5,6 +5,8 @@
 
 package org.opensearch.sql.ast.expression;
 
+import static org.opensearch.sql.utils.QueryStringUtils.maskField;
+
 import java.util.Arrays;
 import java.util.List;
 import lombok.EqualsAndHashCode;
@@ -63,6 +65,12 @@ public String toQueryString() {
     }
   }
 
+  @Override
+  public String toAnonymizedString() {
+    String fieldName = QueryStringUtils.escapeFieldName(field.getField().toString());
+    return maskField(fieldName) + " " + operator.symbol + " ***";
+  }
+
   @Override
   public List<? extends UnresolvedExpression> getChild() {
     return Arrays.asList(field, value);

core/src/main/java/org/opensearch/sql/ast/expression/SearchExpression.java

@@ -17,6 +17,13 @@ public abstract class SearchExpression extends UnresolvedExpression {
    */
   public abstract String toQueryString();
 
+  /**
+   * Convert the search expression to anonymized string
+   *
+   * @return the anonymized string
+   */
+  public abstract String toAnonymizedString();
+
   @Override
   public <R, C> R accept(AbstractNodeVisitor<R, C> nodeVisitor, C context) {
     return nodeVisitor.visitChildren(this, context);

core/src/main/java/org/opensearch/sql/ast/expression/SearchGroup.java

@@ -26,6 +26,14 @@ public String toQueryString() {
     return "(" + expression.toQueryString() + ")";
   }
 
+  @Override
+  public String toAnonymizedString() {
+    if (expression instanceof SearchGroup) {
+      return expression.toAnonymizedString();
+    }
+    return "(" + expression.toAnonymizedString() + ")";
+  }
+
   @Override
   public List<? extends UnresolvedExpression> getChild() {
     return Collections.singletonList(expression);

core/src/main/java/org/opensearch/sql/ast/expression/SearchIn.java

@@ -33,6 +33,11 @@ public String toQueryString() {
     return fieldName + ":( " + valueList + " )";
   }
 
+  @Override
+  public String toAnonymizedString() {
+    return "identifier IN ***";
+  }
+
   @Override
   public List<? extends UnresolvedExpression> getChild() {
     List<UnresolvedExpression> children = new ArrayList<>();

core/src/main/java/org/opensearch/sql/ast/expression/SearchLiteral.java

@@ -55,6 +55,11 @@ public String toQueryString() {
     return QueryStringUtils.escapeLuceneSpecialCharacters(text);
   }
 
+  @Override
+  public String toAnonymizedString() {
+    return "***";
+  }
+
   @Override
   public List<? extends UnresolvedExpression> getChild() {
     return Collections.singletonList(literal);

core/src/main/java/org/opensearch/sql/ast/expression/SearchNot.java

@@ -26,6 +26,11 @@ public String toQueryString() {
     return "NOT(" + expression.toQueryString() + ")";
   }
 
+  @Override
+  public String toAnonymizedString() {
+    return "NOT(" + expression.toAnonymizedString() + ")";
+  }
+
   @Override
   public List<? extends UnresolvedExpression> getChild() {
     return Collections.singletonList(expression);

core/src/main/java/org/opensearch/sql/ast/expression/SearchOr.java

@@ -27,6 +27,11 @@ public String toQueryString() {
     return left.toQueryString() + " OR " + right.toQueryString();
   }
 
+  @Override
+  public String toAnonymizedString() {
+    return left.toAnonymizedString() + " OR " + right.toAnonymizedString();
+  }
+
   @Override
   public List<? extends UnresolvedExpression> getChild() {
     return Arrays.asList(left, right);

core/src/main/java/org/opensearch/sql/ast/tree/Search.java

@@ -7,24 +7,33 @@
 
 import com.google.common.collect.ImmutableList;
 import java.util.List;
+import javax.annotation.Nullable;
 import lombok.EqualsAndHashCode;
 import lombok.Getter;
 import lombok.RequiredArgsConstructor;
 import lombok.ToString;
 import org.opensearch.sql.ast.AbstractNodeVisitor;
+import org.opensearch.sql.ast.expression.SearchExpression;
 
 /**
  * Logical plan node for Search operation. Represents search expressions that get converted to
  * query_string function.
  */
 @Getter
 @ToString
-@EqualsAndHashCode(callSuper = false)
+@EqualsAndHashCode(onlyExplicitlyIncluded = true, callSuper = false)
 @RequiredArgsConstructor
 public class Search extends UnresolvedPlan {
 
-  private final UnresolvedPlan child;
-  private final String queryString;
+  @EqualsAndHashCode.Include private final UnresolvedPlan child;
+  @EqualsAndHashCode.Include private final String queryString;
+
+  // Currently it's only for anonymizer
+  private final @Nullable SearchExpression originalExpression;
+
+  public Search(UnresolvedPlan child, String queryString) {
+    this(child, queryString, null);
+  }
 
   @Override
   public List<UnresolvedPlan> getChild() {
@@ -38,6 +47,6 @@ public <T, C> T accept(AbstractNodeVisitor<T, C> nodeVisitor, C context) {
 
   @Override
   public UnresolvedPlan attach(UnresolvedPlan child) {
-    return new Search(child, queryString);
+    return new Search(child, queryString, originalExpression);
   }
 }