[ES|QL] Add optional parameters support to KQL function

docs/changelog/135895.yaml

@@ -0,0 +1,6 @@
+pr: 135895
+summary: Add optional parameters support to KQL function
+area: ES|QL
+type: enhancement
+issues:
+ - 135823

x-pack/plugin/esql/qa/testFixtures/src/main/resources/kql-function.csv-spec

@@ -287,3 +287,106 @@ c: long     |   scalerank: long
 10             | 3              
 15             | 2              
 ;
+
+kqlWithOptions
+required_capability: kql_function
+required_capability: kql_function_options
+
+
+FROM employees 
+| WHERE KQL("first_name: Mary", {"case_insensitive": false})
+| KEEP emp_no, first_name, last_name
+;
+
+emp_no:integer | first_name:keyword | last_name:keyword
+10011          | Mary               | Sluis
+;
+
+kqlWithCaseInsensitiveOption
+required_capability: kql_function
+required_capability: kql_function_options
+
+FROM employees 
+| WHERE KQL("first_name: mary", {"case_insensitive": true})
+| KEEP emp_no, first_name, last_name
+;
+
+emp_no:integer | first_name:keyword | last_name:keyword
+10011          | Mary               | Sluis
+;
+
+kqlWithTimeZoneOption
+required_capability: kql_function
+required_capability: kql_function_options
+
+FROM logs
+| WHERE KQL("@timestamp > \"2023-10-23T09:56:00\" AND @timestamp < \"2023-10-23T09:57:00\"", {"time_zone": "America/New_York"})
+| KEEP @timestamp, message
+| SORT @timestamp ASC
+;
+
+@timestamp:date          | message:text
+2023-10-23T13:56:01.543Z | No response
+2023-10-23T13:56:01.544Z | Running cats (cycle 2)
+;
+
+kqlWithDefaultFieldOption
+required_capability: kql_function
+required_capability: kql_function_options
+
+FROM employees
+| WHERE KQL("Support Engineer", {"default_field": "job_positions"})
+| KEEP emp_no, first_name, last_name, job_positions
+| SORT emp_no
+| LIMIT 3
+;
+
+emp_no:integer | first_name:keyword | last_name:keyword | job_positions:keyword
+10004          | Chirstian          | Koblick           | [Head Human Resources, Reporting Analyst, Support Engineer, Tech Lead]
+10015          | Guoxiang           | Nooteboom         | [Head Human Resources, Junior Developer, Principal Support Engineer, Support Engineer]
+10021          | Ramzi              | Erde              | Support Engineer
+;
+
+kqlWithBoostOption
+required_capability: kql_function
+required_capability: kql_function_options
+
+FROM employees METADATA _score
+| WHERE KQL("job_positions: Support Engineer", {"boost": 2.5})
+| KEEP emp_no, first_name, last_name, job_positions
+| SORT emp_no
+| LIMIT 3
+;
+
+emp_no:integer | first_name:keyword | last_name:keyword | job_positions:keyword                                                                 
+10004          | Chirstian          | Koblick           | [Head Human Resources, Reporting Analyst, Support Engineer, Tech Lead]                
+10015          | Guoxiang           | Nooteboom         | [Head Human Resources, Junior Developer, Principal Support Engineer, Support Engineer]
+10021          | Ramzi              | Erde              | Support Engineer                                                                      
+;
+
+kqlWithMultipleOptions
+required_capability: kql_function
+required_capability: kql_function_options
+// tag::kql-with-options[]
+FROM employees
+| WHERE KQL("mary", {"case_insensitive": true, "default_field": "first_name", "boost": 1.5})
+// end::kql-with-options[]
+| KEEP emp_no, first_name, last_name
+;
+
+emp_no:integer | first_name:keyword | last_name:keyword
+10011          | Mary               | Sluis
+;
+
+kqlWithWildcardDefaultField
+required_capability: kql_function
+required_capability: kql_function_options
+
+FROM employees
+| WHERE KQL("Mary", {"default_field": "*_name"})
+| KEEP emp_no, first_name, last_name
+;
+
+emp_no:integer | first_name:keyword | last_name:keyword
+10011          | Mary               | Sluis
+;

x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/action/EsqlCapabilities.java

@@ -734,6 +734,11 @@ public enum Cap {
          */
         KQL_FUNCTION,
 
+        /**
+         * Support for optional parameters in KQL function (case_insensitive, time_zone, default_field, boost).
+         */
+        KQL_FUNCTION_OPTIONS,
+
         /**
          * Hash function
          */

x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/expression/function/EsqlFunctionRegistry.java

@@ -504,7 +504,7 @@ private static FunctionDefinition[][] functions() {
             // fulltext functions
             new FunctionDefinition[] {
                 def(Decay.class, quad(Decay::new), "decay"),
-                def(Kql.class, uni(Kql::new), "kql"),
+                def(Kql.class, bi(Kql::new), "kql"),
                 def(Knn.class, tri(Knn::new), "knn"),
                 def(Match.class, tri(Match::new), "match"),
                 def(MultiMatch.class, MultiMatch::new, "multi_match"),