Invalid calls to POST …/scale return JSON parse errors

[backspace]

While reviewing #8207, I thought I’d manipulate the calls to POST /v1/job/:job/scale to see what would happen if I passed invalid Count values.

With "Count":1.5 the response was:

json: cannot unmarshal number 1.5 into Go struct field ScalingRequest.Count of type int64

With "Count":"xyz" the response was:

json: cannot unmarshal string into Go struct field ScalingRequest.Count of type int64

Both of these responses came with HTTP status 400.

Example cURL

curl 'http://localhost:4300/v1/job/api/scale' \                                  
  -H 'content-type: application/json; charset=UTF-8' \
  --data-binary '{"Count":"xyz","Reason":"Manual scaling event from the Nomad UI","Target":{"Group":"endpoints"},"Meta":{"Source":"nomad-ui"}}' \

It would be nice from an API consumer perspective for these responses to come as JSON, perhaps status 422?