elasticsearch return specific fields code example

Example 1: elasticsearch query gettign fields

{
    "_source": ["field_x", ..., "field_y"],
    "query": {      
        ...
    }
}

Example 2: elastic get data from specific fields

{
    "_source": ["user", "message", ...],
    "query": ...,
    "size": ...
}

Example 3: elasticsearch select fields

"_source": ["user", "message", ...],