Getting a Bad response - 422 from the server while sending a POST request in GO

I am trying to send a POST request using this function -
{

  func (Client *Client) doModify(method string, url string, createObj interface{}, respObject interface{}) error {

	bodyContent, err := json.Marshal(createObj)
	if err != nil {
		return err
	}

	client := Client.newHttpClient()

	req, err := http.NewRequest(method, url, bytes.NewBuffer(bodyContent))
	if err != nil {
		return err
	}

	Client.setupRequest(req)
	req.Header.Set("Content-Type", "application/json")
	req.Header.Set("Content-Length", string(len(bodyContent)))

	resp, err := client.Do(req)

	if err != nil {
		return err
	}

	defer resp.Body.Close()

	if resp.StatusCode >= 300 {
		return errors.New(fmt.Sprintf("Bad response from [%s], go [%d]", url, resp.StatusCode))
	}

	byteContent, err := ioutil.ReadAll(resp.Body)
	if err != nil {
		return err
	}

	return json.Unmarshal(byteContent, respObject)
}

}

I am calling my function like this -

{

    func TestContainerCreate(t *testing.T) {
	client := newClient(t)
	container, err := client.Container.Create(&Container{
		Name:      "name",
		ImageUuid: "xyz",
	})

	if err != nil {
		t.Fatal(err)
	}

	defer client.Container.Delete(container)

}

}

The Create function calls internally calls the doCreate function which calls the doModify function pasted on the top .
{

func (self *ContainerClient) Create(container *Container) (*Container, error) {
	resp := &Container{}
	err := self.Client.doCreate(container_TYPE, container, resp)
	return resp, err
}

}

{

   func (Client *Client) doCreate(schemaType string, createObj interface{}, respObject interface{}) error {
    	if createObj == nil {
    		createObj = map[string]string{}
    	}
    
    	schema, ok := Client.Types[schemaType]
    	if !ok {
    		return errors.New("Unknown schema type [" + schemaType + "]")
    	}
    
    	return Client.doModify("POST", collectionUrl, createObj, respObject)
    }

}

This gives me a 422 bad response.On doing further research, When doing a CURL, with "name" and "imageUuid" first letter as small case, gives a 201 created status but when passing "Name" and "ImageUuid" first letter as capital gives 422 bad response. Could there be issue with the json struct defined for container, or case of these entities being defined or something else?
{

curl -X POST -v -s http://localhost:8080/v1/containers -H 'Content-Type: application/json' -d '{"name" : "demo", "imageUuid" : "docker:nginx"}'   | python -m 'json.tool'

}

Container struct definition looks like this -
{

type Container struct {
	Resource

	ImageId string `json:"ImageId,omitempty"`

	ImageUuid string `json:"ImageUuid,omitempty"`

	MemoryMb int `json:"MemoryMb,omitempty"`

	Name string `json:"Name,omitempty"`

}

type ContainerCollection struct {
	Collection
	Data []Container `json:"data,omitempty"`
}

}

string(len(bodyContent)) isn't doing what you think it is. You're converting a single int to a utf-8 string. You want to use the strconv package to get the numerical representation.

Also note that you can't omitempty an int, since 0 is a valid value.