Why my geoip lookup is failing?

Elastic Stack Logstash
2

If you are running in ECS mode v8 (the default) then you should be getting an error message for each lookup

GeoIP Filter in ECS-Compatiblity mode requires a target when source is not an ip sub-field, eg. [client][ip]>,

If you change your mutate to

mutate { rename => { "source_ip" => "[source][ip]" } }

then you will get

    "source" => {
     "ip" => "103.161.42.21",
    "geo" => {
                "location" => {
            "lon" => 79.0011,
            "lat" => 21.9974
        },
        "country_iso_code" => "IN",
                "timezone" => "Asia/Kolkata",
          "continent_code" => "AS",
            "country_name" => "India"
    }