Create Dashboards from log file entry key value pairs

If I have a following JSON entries in a log file, Can I create average response time over the time graphs. So I need to extract response_time json attribute value and create a graph out of it. I need to create Grafana dashboards similar to this for different keys present in the log entry

{ proxy": "SimpleProxy","response_time": "200.0", acivityId:"aaaaa"}