feature(worker): implemented Worker object, worker side code is almost done

internal/util.go

@@ -0,0 +1,79 @@
+package internal
+
+import (
+	"bytes"
+	"crypto/tls"
+	"crypto/x509"
+	"encoding/json"
+	"errors"
+	"io/ioutil"
+	"net/http"
+)
+
+// GetTLSConfig generate tls.Config from CAFile
+func GetTLSConfig(CAFile string) (*tls.Config, error) {
+	caCert, err := ioutil.ReadFile(CAFile)
+	if err != nil {
+		return nil, err
+	}
+	caCertPool := x509.NewCertPool()
+	if ok := caCertPool.AppendCertsFromPEM(caCert); !ok {
+		return nil, errors.New("Failed to add CA to pool")
+	}
+
+	tlsConfig := &tls.Config{
+		RootCAs: caCertPool,
+	}
+	tlsConfig.BuildNameToCertificate()
+	return tlsConfig, nil
+}
+
+// PostJSON posts json object to url
+func PostJSON(url string, obj interface{}, tlsConfig *tls.Config) (*http.Response, error) {
+	var client *http.Client
+	if tlsConfig == nil {
+		client = &http.Client{}
+	} else {
+		tr := &http.Transport{
+			TLSClientConfig: tlsConfig,
+		}
+		client = &http.Client{
+			Transport: tr,
+		}
+	}
+
+	b := new(bytes.Buffer)
+	if err := json.NewEncoder(b).Encode(obj); err != nil {
+		return nil, err
+	}
+	return client.Post(url, "application/json; charset=utf-8", b)
+}
+
+// GetJSON gets a json response from url
+func GetJSON(url string, obj interface{}, tlsConfig *tls.Config) (*http.Response, error) {
+	var client *http.Client
+	if tlsConfig == nil {
+		client = &http.Client{}
+	} else {
+		tr := &http.Transport{
+			TLSClientConfig: tlsConfig,
+		}
+		client = &http.Client{
+			Transport: tr,
+		}
+	}
+
+	resp, err := client.Get(url)
+	if err != nil {
+		return resp, err
+	}
+	if resp.StatusCode != http.StatusOK {
+		return resp, errors.New("HTTP status code is not 200")
+	}
+	defer resp.Body.Close()
+	body, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		return resp, err
+	}
+	return resp, json.Unmarshal(body, obj)
+}