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/api.go

@@ -20,6 +20,8 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
+	"github.com/hashicorp/go-multierror"
+	"github.com/pkg/errors"
 	"io/ioutil"
 	"net/http"
 	"strings"
@@ -32,6 +34,7 @@ import (
 
 	fv1 "github.com/fission/fission/pkg/apis/fission.io/v1"
 	ferror "github.com/fission/fission/pkg/error"
+	"github.com/fission/fission/pkg/executor/client"
 )
 
 func (executor *Executor) getServiceForFunctionApi(w http.ResponseWriter, r *http.Request) {
@@ -115,6 +118,7 @@ func (executor *Executor) getServiceForFunction(fn *fv1.Function) (string, error
 }
 
 // find funcSvc and update its atime
+// TODO: Deprecated tapService
 func (executor *Executor) tapService(w http.ResponseWriter, r *http.Request) {
 	body, err := ioutil.ReadAll(r.Body)
 	if err != nil {
@@ -137,6 +141,45 @@ func (executor *Executor) tapService(w http.ResponseWriter, r *http.Request) {
 	w.WriteHeader(http.StatusOK)
 }
 
+// find funcSvc and update its atime
+func (executor *Executor) tapServices(w http.ResponseWriter, r *http.Request) {
+	body, err := ioutil.ReadAll(r.Body)
+	if err != nil {
+		executor.logger.Error("failed to read tap service request", zap.Error(err))
+		http.Error(w, "Failed to read request", http.StatusInternalServerError)
+		return
+	}
+
+	tapSvcReqs := []client.TapServiceRequest{}
+	err = json.Unmarshal(body, &tapSvcReqs)
+	if err != nil {
+		executor.logger.Error("failed to decode tap service request",
+			zap.Error(err),
+			zap.String("request-payload", string(body)))
+		http.Error(w, "Failed to decode tap service request", http.StatusBadRequest)
+		return
+	}
+
+	errs := &multierror.Error{}
+	for _, req := range tapSvcReqs {
+		svcHost := strings.TrimPrefix(req.ServiceUrl, "http://")
+		err = executor.fsCache.TouchByAddress(svcHost)
+		if err != nil {
+			errs = multierror.Append(errs,
+				errors.Wrapf(err, "'%v' failed to tap function '%v/%v' with service url '%v'",
+					req.FnMetadata.Namespace, req.FnMetadata.Name, req.ServiceUrl, req.FnExecutorType))
+		}
+	}
+
+	if errs.ErrorOrNil() != nil {
+		executor.logger.Error("error tapping function service", zap.Error(errs))
+		http.Error(w, "Not found", http.StatusNotFound)
+		return
+	}
+
+	w.WriteHeader(http.StatusOK)
+}
+
 func (executor *Executor) healthHandler(w http.ResponseWriter, r *http.Request) {
 	w.WriteHeader(http.StatusOK)
 }
@@ -144,7 +187,8 @@ func (executor *Executor) healthHandler(w http.ResponseWriter, r *http.Request)
 func (executor *Executor) GetHandler() http.Handler {
 	r := mux.NewRouter()
 	r.HandleFunc("/v2/getServiceForFunction", executor.getServiceForFunctionApi).Methods("POST")
-	r.HandleFunc("/v2/tapService", executor.tapService).Methods("POST")
+	r.HandleFunc("/v2/tapService", executor.tapService).Methods("POST") // for backward compatibility
+	r.HandleFunc("/v2/tapServices", executor.tapServices).Methods("POST")
 	r.HandleFunc("/healthz", executor.healthHandler).Methods("GET")
 	return r
 }