Add support for ephemeral runtime fields #61298
Description
Once we have added support for runtime fields added to index mappings (#59332), we'd like to make it possible to make them available in the context of a specific search request. A new section of the search request would be added, which allows to create runtime fields on-the-fly. In that case such fields are available only within the execution of that specific search request.
The following is an example of how a runtime scripted field can be made available in the context of a search request:
GET my_index/_search
{
"runtime_mappings": {
"age": {
"type" : "runtime_script",
"runtime_type": "integer",
"script": {
"source" : "now - doc['date_of_birth'].value"
}
}
},
"query": {
"range" : {
"age" : {
"gte" : 10,
"lte" : 20
}
}
},
"sort" : ["age"],
"aggs" : {
"age" : {
"terms" : {
"field" : "age"
}
}
}
}