Allow to tap multiple function services at one time (#1434)

The router taps function service one by one which is inefficient and
increases the burden of executor. This PR aggregates all requests into
one to solve the problem mentioned above.

pkg/executor/client/client.go

@@ -26,29 +26,36 @@ import (
 	"strings"
 	"time"
 
+	fv1 "github.com/fission/fission/pkg/apis/fission.io/v1"
+	ferror "github.com/fission/fission/pkg/error"
 	"github.com/pkg/errors"
 	"go.opencensus.io/plugin/ochttp"
 	"go.uber.org/zap"
 	"golang.org/x/net/context/ctxhttp"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
-
-	ferror "github.com/fission/fission/pkg/error"
 )
 
-type Client struct {
-	logger      *zap.Logger
-	executorUrl string
-	tappedByUrl map[string]bool
-	requestChan chan string
-	httpClient  *http.Client
-}
+type (
+	Client struct {
+		logger      *zap.Logger
+		executorUrl string
+		tappedByUrl map[string]TapServiceRequest
+		requestChan chan TapServiceRequest
+		httpClient  *http.Client
+	}
+	TapServiceRequest struct {
+		FnMetadata     metav1.ObjectMeta
+		FnExecutorType fv1.ExecutorType
+		ServiceUrl     string
+	}
+)
 
 func MakeClient(logger *zap.Logger, executorUrl string) *Client {
 	c := &Client{
 		logger:      logger.Named("executor_client"),
 		executorUrl: strings.TrimSuffix(executorUrl, "/"),
-		tappedByUrl: make(map[string]bool),
-		requestChan: make(chan string),
+		tappedByUrl: make(map[string]TapServiceRequest),
+		requestChan: make(chan TapServiceRequest),
 		httpClient: &http.Client{
 			Transport: &ochttp.Transport{},
 		},
@@ -87,40 +94,64 @@ func (c *Client) service() {
 	ticker := time.NewTicker(time.Second * 5)
 	for {
 		select {
-		case serviceUrl := <-c.requestChan:
-			c.tappedByUrl[serviceUrl] = true
+		case svcReq := <-c.requestChan:
+			c.tappedByUrl[svcReq.ServiceUrl] = svcReq
 		case <-ticker.C:
-			urls := c.tappedByUrl
-			c.tappedByUrl = make(map[string]bool)
-			if len(urls) > 0 {
-				go func() {
-					for u := range urls {
-						err := c._tapService(u)
-						if err != nil {
-							c.logger.Error("error tapping function service address", zap.Error(err), zap.String("address", u))
-						}
-					}
-					c.logger.Debug("tapped services in batch", zap.Int("service_count", len(urls)))
-				}()
+			if len(c.tappedByUrl) == 0 {
+				continue
 			}
+
+			urls := c.tappedByUrl
+			c.tappedByUrl = make(map[string]TapServiceRequest)
+
+			go func() {
+				svcReqs := []TapServiceRequest{}
+				for _, req := range urls {
+					svcReqs = append(svcReqs, req)
+				}
+				c.logger.Debug("tapped services in batch", zap.Int("service_count", len(urls)))
+
+				err := c._tapService(svcReqs)
+				if err != nil {
+					c.logger.Error("error tapping function service address", zap.Error(err))
+				}
+			}()
 		}
 	}
 }
 
-func (c *Client) TapService(serviceUrl *url.URL) {
-	c.requestChan <- serviceUrl.String()
+func (c *Client) TapService(fnMeta metav1.ObjectMeta, executorType fv1.ExecutorType, serviceUrl *url.URL) {
+	c.requestChan <- TapServiceRequest{
+		FnMetadata: metav1.ObjectMeta{
+			Name:            fnMeta.Name,
+			Namespace:       fnMeta.Namespace,
+			ResourceVersion: fnMeta.ResourceVersion,
+			UID:             fnMeta.UID,
+		},
+		FnExecutorType: executorType,
+		// service url is for executor to know which
+		// pod/service is currently used to serve user function.
+		ServiceUrl: serviceUrl.String(),
+	}
 }
 
-func (c *Client) _tapService(serviceUrlStr string) error {
-	executorUrl := c.executorUrl + "/v2/tapService"
+func (c *Client) _tapService(tapSvcReqs []TapServiceRequest) error {
+	executorUrl := c.executorUrl + "/v2/tapServices"
 
-	resp, err := http.Post(executorUrl, "application/octet-stream", bytes.NewReader([]byte(serviceUrlStr)))
+	body, err := json.Marshal(tapSvcReqs)
+	if err != nil {
+		return err
+	}
+
+	resp, err := http.Post(executorUrl, "application/json", bytes.NewReader(body))
 	if err != nil {
 		return err
 	}
 	defer resp.Body.Close()
+
 	if resp.StatusCode != 200 {
 		return ferror.MakeErrorFromHTTP(resp)
 	}
+
 	return nil
 }