cleanup: Remove Opentracing support as no active users (#2196)

References:
[1] #2193
[2] https://fissionio.slack.com/archives/C3LUX6BBP/p1631706812069300

Signed-off-by: Sanket Sudake <sanketsudake@gmail.com>

pkg/router/functionHandler.go

@@ -30,7 +30,6 @@ import (
 	"time"
 
 	"github.com/pkg/errors"
-	"go.opencensus.io/plugin/ochttp"
 	"go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp"
 	"go.uber.org/zap"
 	k8stypes "k8s.io/apimachinery/pkg/types"
@@ -68,7 +67,6 @@ type (
 		svcAddrUpdateThrottler   *throttler.Throttler
 		functionTimeoutMap       map[k8stypes.UID]int
 		unTapServiceTimeout      time.Duration
-		openTracingEnabled       bool
 	}
 
 	tsRoundTripperParams struct {
@@ -323,15 +321,14 @@ func (roundTripper *RetryingRoundTripper) RoundTrip(req *http.Request) (*http.Re
 		// The otelhttp.NewTransport() does not work with WebSocket.
 		// This is probably because it modifies the response body.
 		// Until we find a better solution to handle websocket requests, we will continue to
-		// use ochttp.Transport(). We check if the request isWebsocketRequest() and use the
-		// ochttp.Transport() irrespective of open telemetry is enabled or not.
+		// use http.Transport(). We check if the request isWebsocketRequest() and use the
+		// http.Transport() irrespective of open telemetry is enabled or not.
 		// Related issue: https://github.com/open-telemetry/opentelemetry-js-contrib/issues/12
 
 		// forward the request to the function service
 		var resp *http.Response
-		if roundTripper.funcHandler.openTracingEnabled || util.IsWebsocketRequest(newReq) {
-			ocRoundTripper := &ochttp.Transport{Base: transport}
-			resp, err = ocRoundTripper.RoundTrip(newReq)
+		if util.IsWebsocketRequest(newReq) {
+			resp, err = transport.RoundTrip(newReq)
 		} else {
 			otelUtils.SpanTrackEvent(ctx, "roundtrip", otelUtils.MapToAttributes(map[string]string{
 				"function-name":      fnMeta.Name,

pkg/router/httpTriggers.go

@@ -37,7 +37,6 @@ import (
 	"github.com/fission/fission/pkg/utils"
 	"github.com/fission/fission/pkg/utils/metrics"
 	"github.com/fission/fission/pkg/utils/otel"
-	"github.com/fission/fission/pkg/utils/tracing"
 )
 
 // HTTPTriggerSet represents an HTTP trigger set
@@ -122,8 +121,6 @@ func (ts *HTTPTriggerSet) getRouter(fnTimeoutMap map[types.UID]int) *mux.Router
 		muxRouter.Use(authMiddleware(featureConfig))
 	}
 
-	openTracingEnabled := tracing.TracingEnabled(ts.logger)
-
 	// HTTP triggers setup by the user
 	homeHandled := false
 	for i := range ts.triggers {
@@ -157,7 +154,6 @@ func (ts *HTTPTriggerSet) getRouter(fnTimeoutMap map[types.UID]int) *mux.Router
 			svcAddrUpdateThrottler:   ts.svcAddrUpdateThrottler,
 			functionTimeoutMap:       fnTimeoutMap,
 			unTapServiceTimeout:      ts.unTapServiceTimeout,
-			openTracingEnabled:       openTracingEnabled,
 		}
 
 		// The functionHandler for HTTP trigger with fn reference type "FunctionReferenceTypeFunctionName",
@@ -188,14 +184,10 @@ func (ts *HTTPTriggerSet) getRouter(fnTimeoutMap map[types.UID]int) *mux.Router
 		}
 
 		var handler http.Handler
-		if openTracingEnabled {
-			handler = http.HandlerFunc(fh.handler)
+		if trigger.Spec.Prefix != nil && *trigger.Spec.Prefix != "" {
+			handler = otel.GetHandlerWithOTEL(http.HandlerFunc(fh.handler), *trigger.Spec.Prefix)
 		} else {
-			if trigger.Spec.Prefix != nil && *trigger.Spec.Prefix != "" {
-				handler = otel.GetHandlerWithOTEL(http.HandlerFunc(fh.handler), *trigger.Spec.Prefix)
-			} else {
-				handler = otel.GetHandlerWithOTEL(http.HandlerFunc(fh.handler), trigger.Spec.RelativeURL)
-			}
+			handler = otel.GetHandlerWithOTEL(http.HandlerFunc(fh.handler), trigger.Spec.RelativeURL)
 		}
 
 		if trigger.Spec.Prefix != nil && *trigger.Spec.Prefix != "" {
@@ -263,11 +255,7 @@ func (ts *HTTPTriggerSet) getRouter(fnTimeoutMap map[types.UID]int) *mux.Router
 		var handler http.Handler
 		internalRoute := utils.UrlForFunction(fn.ObjectMeta.Name, fn.ObjectMeta.Namespace)
 		internalPrefixRoute := internalRoute + "/"
-		if openTracingEnabled {
-			handler = http.HandlerFunc(fh.handler)
-		} else {
-			handler = otel.GetHandlerWithOTEL(http.HandlerFunc(fh.handler), internalRoute)
-		}
+		handler = otel.GetHandlerWithOTEL(http.HandlerFunc(fh.handler), internalRoute)
 
 		muxRouter.Handle(internalRoute, handler)
 		muxRouter.PathPrefix(internalPrefixRoute).Handler(handler)

pkg/router/router.go

@@ -42,16 +42,11 @@ package router
 import (
 	"context"
 	"fmt"
-	"net/http"
-	"net/http/httputil"
 	"os"
 	"strconv"
-	"strings"
 	"time"
 
 	"github.com/gorilla/mux"
-	"go.opencensus.io/plugin/ochttp"
-	"go.opencensus.io/trace"
 	"go.opentelemetry.io/otel"
 	"go.uber.org/zap"
 
@@ -85,41 +80,14 @@ func router(ctx context.Context, logger *zap.Logger, httpTriggerSet *HTTPTrigger
 }
 
 func serve(ctx context.Context, logger *zap.Logger, port int, tracingSamplingRate float64,
-	httpTriggerSet *HTTPTriggerSet, displayAccessLog bool, openTracingEnabled bool) {
+	httpTriggerSet *HTTPTriggerSet, displayAccessLog bool) {
 	mr := router(ctx, logger, httpTriggerSet)
-
-	var handler http.Handler
-	if openTracingEnabled {
-		handler = &ochttp.Handler{
-			Handler: mr,
-			GetStartOptions: func(r *http.Request) trace.StartOptions {
-				// do not trace router healthz endpoint
-				if strings.Compare(r.URL.Path, "/router-healthz") == 0 {
-					return trace.StartOptions{
-						Sampler: trace.NeverSample(),
-					}
-				}
-				if displayAccessLog {
-					reqMsg, err := httputil.DumpRequest(r, false)
-					if err != nil {
-						logger.Error("error dumping request", zap.Error(err))
-					}
-					logger.Info("request dump", zap.String("request", string(reqMsg)))
-				}
-				return trace.StartOptions{
-					Sampler: trace.ProbabilitySampler(tracingSamplingRate),
-				}
-			},
-		}
-	} else {
-		handler = otelUtils.GetHandlerWithOTEL(mr, "fission-router", otelUtils.UrlsToIgnore("/router-healthz"))
-	}
-
+	handler := otelUtils.GetHandlerWithOTEL(mr, "fission-router", otelUtils.UrlsToIgnore("/router-healthz"))
 	httpserver.StartServer(ctx, logger, "router", fmt.Sprintf("%d", port), handler)
 }
 
 // Start starts a router
-func Start(ctx context.Context, logger *zap.Logger, port int, executorURL string, openTracingEnabled bool) {
+func Start(ctx context.Context, logger *zap.Logger, port int, executorURL string) {
 	fmap := makeFunctionServiceMap(logger, time.Minute)
 
 	fissionClient, kubeClient, _, _, err := crd.MakeFissionClient()
@@ -254,5 +222,5 @@ func Start(ctx context.Context, logger *zap.Logger, port int, executorURL string
 	ctx, span := tracer.Start(ctx, "router/Start")
 	defer span.End()
 
-	serve(ctx, logger, port, tracingSamplingRate, triggers, displayAccessLog, openTracingEnabled)
+	serve(ctx, logger, port, tracingSamplingRate, triggers, displayAccessLog)
 }