Regex query from Kibana discovery tab over logs from logstash - elasticsearch

Question

I am trying to find a way to match the below line with either KQL or Lucene query from Kibana discovery. The value I am trying to match is in field "message" which is of type "text".
message: Starting <app_name> v1.7.0-SNAPSHOT on ...
Tried with below query:
message: /Starting\s[a-ZA-Z] v/
Application Stack:
logstash-7.10.0
Kibana 7.6.1
elasticsearch 7.6.1
Index Name: logstash-filebeat-7.10.0
Index Mappings:
{
"mapping": {
"_doc": {
"dynamic": "true",
"_meta": {},
"_source": {
"includes": [],
"excludes": []
},
"dynamic_date_formats": [
"strict_date_optional_time",
"yyyy/MM/dd HH:mm:ss Z||yyyy/MM/dd Z"
],
"dynamic_templates": [
{
"message_field": {
"path_match": "message",
"match_mapping_type": "string",
"mapping": {
"norms": false,
"type": "text"
}
}
},
{
"string_fields": {
"match": "*",
"match_mapping_type": "string",
"mapping": {
"fields": {
"keyword": {
"ignore_above": 256,
"type": "keyword"
}
},
"norms": false,
"type": "text"
}
}
}
],
"date_detection": true,
"numeric_detection": false,
"properties": {
"#timestamp": {
"type": "date"
},
"#version": {
"type": "keyword"
},
"agent": {
"properties": {
"hostname": {
"type": "text",
"norms": false,
"fields": {
"keyword": {
"type": "keyword",
"ignore_above": 256
}
}
},
"name": {
"type": "text",
"norms": false,
"fields": {
"keyword": {
"type": "keyword",
"ignore_above": 256
}
}
},
"type": {
"type": "text",
"norms": false,
"fields": {
"keyword": {
"type": "keyword",
"ignore_above": 256
}
}
},
"version": {
"type": "text",
"norms": false,
"fields": {
"keyword": {
"type": "keyword",
"ignore_above": 256
}
}
}
}
},
"classname": {
"type": "text",
"norms": false,
"fields": {
"keyword": {
"type": "keyword",
"ignore_above": 256
}
}
},
"container": {
"properties": {
"id": {
"type": "text",
"norms": false,
"fields": {
"keyword": {
"type": "keyword",
"ignore_above": 256
}
}
}
}
},
"ecs": {
"properties": {
"version": {
"type": "text",
"norms": false,
"fields": {
"keyword": {
"type": "keyword",
"ignore_above": 256
}
}
}
}
},
"geoip": {
"dynamic": "true",
"properties": {
"ip": {
"type": "ip"
},
"latitude": {
"type": "half_float"
},
"location": {
"type": "geo_point"
},
"longitude": {
"type": "half_float"
}
}
},
"input": {
"properties": {
"type": {
"type": "text",
"norms": false,
"fields": {
"keyword": {
"type": "keyword",
"ignore_above": 256
}
}
}
}
},
"log": {
"properties": {
"file": {
"properties": {
"path": {
"type": "text",
"norms": false,
"fields": {
"keyword": {
"type": "keyword",
"ignore_above": 256
}
}
}
}
},
"flags": {
"type": "text",
"norms": false,
"fields": {
"keyword": {
"type": "keyword",
"ignore_above": 256
}
}
},
"offset": {
"type": "long"
}
}
},
"loglevel": {
"type": "text",
"norms": false,
"fields": {
"keyword": {
"type": "keyword",
"ignore_above": 256
}
}
},
"message": {
"type": "text",
"norms": false
},
"thread": {
"type": "text",
"norms": false,
"fields": {
"keyword": {
"type": "keyword",
"ignore_above": 256
}
}
}
}
}
}
}