curl --request GET \
  --url https://drb.coinbase.com/api/v2/private/get_open_orders_by_instrument \
  --header 'Content-Type: application/json' \
  --data '
{
  "id": 8442,
  "jsonrpc": "2.0",
  "method": "private/get_open_orders_by_instrument",
  "params": {
    "instrument_name": "ETH-22FEB19-120-C"
  }
}
'

{
  "id": 1953,
  "jsonrpc": "2.0",
  "result": [
    {
      "amount": 10,
      "api": true,
      "average_price": 0,
      "creation_timestamp": 1550050597036,
      "direction": "buy",
      "filled_amount": 0,
      "instrument_name": "BTC-15FEB19-3250-P",
      "is_liquidation": false,
      "is_rebalance": false,
      "label": "fooBar",
      "last_update_timestamp": 1550050597036,
      "max_show": 10,
      "order_id": "146062",
      "order_state": "open",
      "order_type": "limit",
      "post_only": false,
      "price": 0.0028,
      "reduce_only": false,
      "time_in_force": "good_til_cancelled"
    }
  ]
}