fetch.go

func fetchInstances() (map[string]interface{}, error) {
	jsonStr := []byte(`{
		"older_than": ` + olderThan + `,
		"limit": ` + instancesToFetch + `,
	}`)
	req, err := http.NewRequest("GET", fetchInstancesURL, bytes.NewBuffer(jsonStr))
	req.Header.Set("Authorization", apiSecret)
	req.Header.Set("Content-Type", "application/json")
	client := &http.Client{
		Timeout: 30 * time.Second,
	}

	resp, err := client.Do(req)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()

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

	result := map[string]interface{}{}
	err = json.Unmarshal(body, &result)
	if err != nil {
		return nil, err
	}

	return result, nil
}