Split Filter Parse Failure - Only String and Array types are splittable

I have this error with split filter in logstash .
"Only String and Array types are splittable. field:[log] is of type = NilClass"

I am trying to create events for each object in an array of objects but cannot figure out the syntax for array filed which needs to be used in the split filter.

I need to know how to reference the "log" array in the split filter.
Here is my data (this is prettified json) .

{"log": [
	{
	  "agent": "Mozilla/5.0 (compatible; MSIE 9.0)",
	  "ip": "192.168.24.44",
	  "request": "/index.html"
	  "response": {
		"status": 200,
		"bytes": 52353
	  },
	  "ua": {
		"os": "Windows 7"
	  }
	},
	{
	  "agent": "Mozilla/5.0 (compatible; MSIE 9.0)",
	  "ip": "192.168.24.44",
	  "request": "/index.html"
	  "response": {
		"status": 200,
		"bytes": 52353
	  },
	  "ua": {
		"os": "Windows 7"
	  }
	}
]
}

And my config is

input {
  file {
        type => "json"
	codec => multiline {
        pattern => ",\n{"
        negate => true
        what => previous
		auto_flush_interval  => 5
		#max_lines => 20000
      } 
	sincedb_path => "/dev/null"
	start_position => "beginning"
        path => "/etc/logstash/ingest/log.log"
   
  }
}
filter {

	split { 
		field => "[log]" 
		target=> "message"
		terminator => ",\n{"
	}
}
output {
	
	file {
	   path => "/etc/logstash/output/result.txt"
	   codec => "rubydebug"
	 }
}

Any help would be very much appreciated. Thanks

Please use markdown to format your post. Edit your post, select the configuration, and click on </> in the toolbar above the edit pane. Then do the same with your data.

Thanks, I have edited the code section.

Why would you need a split filter if you have already combined each JSON object into a single event using the multiline codec? I would not expect any event except (possibly) the first to contain a [log] field.

For some reason the multiline does not split the obejects. It passes the whole payload to the filters