Add support for comma-separated URLs (#1364)

* Add support for comma-separated URLs

* Fix test

* Minor fix

schemaregistry/internal/client_config.go

@@ -22,7 +22,7 @@ import (
 
 // ClientConfig is used to pass multiple configuration options to the Schema Registry client.
 type ClientConfig struct {
-	// SchemaRegistryURL determines the URL of Schema Registry.
+	// SchemaRegistryURL is a comma-space separated list of URLs for the Schema Registry.
 	SchemaRegistryURL string
 
 	// BasicAuthUserInfo specifies the user info in the form of {username}:{password}.

schemaregistry/internal/rest_service.go

@@ -112,7 +112,7 @@ func NewRequest(method string, endpoint string, body interface{}, arguments ...i
 
 // RestService represents a REST client
 type RestService struct {
-	url              *url.URL
+	urls             []*url.URL
 	headers          http.Header
 	maxRetries       int
 	retriesWaitMs    int
@@ -124,21 +124,22 @@ type RestService struct {
 // NewRestService returns a new REST client for the Confluent Schema Registry
 func NewRestService(conf *ClientConfig) (*RestService, error) {
 	urlConf := conf.SchemaRegistryURL
-	u, err := url.Parse(urlConf)
-
-	if err != nil {
-		return nil, err
+	urlStrs := strings.Split(urlConf, ",")
+	urls := make([]*url.URL, len(urlStrs))
+	for i, urlStr := range urlStrs {
+		u, err := url.Parse(strings.TrimSpace(urlStr))
+		if err != nil {
+			return nil, err
+		}
+		urls[i] = u
 	}
 
-	headers, err := NewAuthHeader(u, conf)
+	headers, err := NewAuthHeader(urls[0], conf)
 	if err != nil {
 		return nil, err
 	}
 
 	headers.Add("Content-Type", "application/vnd.schemaregistry.v1+json")
-	if err != nil {
-		return nil, err
-	}
 
 	if conf.HTTPClient == nil {
 		transport, err := configureTransport(conf)
@@ -155,7 +156,7 @@ func NewRestService(conf *ClientConfig) (*RestService, error) {
 	}
 
 	return &RestService{
-		url:              u,
+		urls:             urls,
 		headers:          headers,
 		maxRetries:       conf.MaxRetries,
 		retriesWaitMs:    conf.RetriesWaitMs,
@@ -337,19 +338,51 @@ func NewAuthHeader(service *url.URL, conf *ClientConfig) (http.Header, error) {
 	return header, err
 }
 
-// HandleRequest sends a HTTP(S) request to the Schema Registry, placing results into the response object
+// HandleRequest sends a request to the Schema Registry, iterating over the list of URLs
 func (rs *RestService) HandleRequest(request *API, response interface{}) error {
-	urlPath := path.Join(rs.url.Path, fmt.Sprintf(request.endpoint, request.arguments...))
-	endpoint, err := rs.url.Parse(urlPath)
-	if err != nil {
+	var resp *http.Response
+	var err error
+	for i, u := range rs.urls {
+		resp, err = rs.HandleHTTPRequest(u, request)
+		if err != nil {
+			if i == len(rs.urls)-1 {
+				return err
+			}
+			continue
+		}
+		if isSuccess(resp.StatusCode) || !isRetriable(resp.StatusCode) || i >= rs.maxRetries {
+			break
+		}
+	}
+	defer resp.Body.Close()
+	if isSuccess(resp.StatusCode) {
+		if err = json.NewDecoder(resp.Body).Decode(response); err != nil {
+			return err
+		}
+		return nil
+	}
+
+	var failure rest.Error
+	if err = json.NewDecoder(resp.Body).Decode(&failure); err != nil {
 		return err
 	}
 
+	return &failure
+}
+
+// HandleHTTPRequest sends a HTTP(S) request to the Schema Registry, placing results into the response object
+func (rs *RestService) HandleHTTPRequest(url *url.URL, request *API) (*http.Response, error) {
+	urlPath := path.Join(url.Path, fmt.Sprintf(request.endpoint, request.arguments...))
+	endpoint, err := url.Parse(urlPath)
+	if err != nil {
+		return nil, err
+	}
+
 	var readCloser io.ReadCloser
 	if request.body != nil {
 		outbuf, err := json.Marshal(request.body)
 		if err != nil {
-			return err
+			return nil, err
 		}
 		readCloser = ioutil.NopCloser(bytes.NewBuffer(outbuf))
 	}
@@ -365,30 +398,16 @@ func (rs *RestService) HandleRequest(request *API, response interface{}) error {
 	for i := 0; i < rs.maxRetries+1; i++ {
 		resp, err = rs.Do(req)
 		if err != nil {
-			return err
+			return nil, err
 		}
 
 		if isSuccess(resp.StatusCode) || !isRetriable(resp.StatusCode) || i >= rs.maxRetries {
-			break
+			return resp, nil
 		}
 
 		time.Sleep(rs.fullJitter(i))
 	}
-
-	defer resp.Body.Close()
-	if resp.StatusCode == 200 {
-		if err = json.NewDecoder(resp.Body).Decode(response); err != nil {
-			return err
-		}
-		return nil
-	}
-
-	var failure rest.Error
-	if err := json.NewDecoder(resp.Body).Decode(&failure); err != nil {
-		return err
-	}
-
-	return &failure
+	return nil, fmt.Errorf("failed to send request after %d retries", rs.maxRetries)
 }
 
 func (rs *RestService) fullJitter(retriesAttempted int) time.Duration {

schemaregistry/serde/avrov2/avro_test.go

@@ -937,6 +937,8 @@ func TestAvroSerdeWithCELFieldTransformDisable(t *testing.T) {
 		OnFailure: nil,
 		Disabled:  &[]bool{true}[0],
 	})
+	ser.RuleRegistry = &registry
+
 	id, err := client.Register("topic1-value", info, false)
 	serde.MaybeFail("Schema registration", err)
 	if id <= 0 {
@@ -960,7 +962,7 @@ func TestAvroSerdeWithCELFieldTransformDisable(t *testing.T) {
 	deser.MessageFactory = testMessageFactory
 
 	newobj, err := deser.Deserialize("topic1", bytes)
-	serde.MaybeFail("deserialization", err, serde.Expect(newobj, &obj))
+	serde.MaybeFail("deserialization", err, serde.Expect(newobj.(*DemoSchema).StringField, "hi"))
 }
 
 func TestAvroSerdeWithCELFieldTransform(t *testing.T) {