Fission meets OpenTelemetry (#2157)

* add opentracing section and otelCollectorEndpoint
* initialize OTLP exporter
* pkg/controller: changes for context propagation
* pkg/executor: changes for context propagation
* pkg/fetcher: changes for context propagation
* pkg/router: changes for context propagation
* pkg/storagesvc: changes for context propagation
* set no default value for otel collector endpoint
* update readme and add notes to charts
* move common code to pkg/utils/otel
* adding fn and env as attributes
* don't use otelhttp transport for websocket
* URL ignore with common filter UrlsToIgnore

Note: The web socket example does not work when using OTEL HTTP. Here is an issue related to that on open-telemetry/opentelemetry-js-contrib.

Signed-off-by: Gaurav Gahlot <gauravgahlot0107@gmail.com>
Co-authored-by: Sanket Sudake <sanketsudake@gmail.com>

pkg/controller/api.go

@@ -24,6 +24,7 @@ import (
 	"strings"
 
 	"github.com/gorilla/mux"
+	"go.opencensus.io/plugin/ochttp"
 	"go.uber.org/zap"
 	apiv1 "k8s.io/api/core/v1"
 	kerrors "k8s.io/apimachinery/pkg/api/errors"
@@ -34,6 +35,7 @@ import (
 	ferror "github.com/fission/fission/pkg/error"
 	"github.com/fission/fission/pkg/fission-cli/logdb"
 	"github.com/fission/fission/pkg/info"
+	"github.com/fission/fission/pkg/utils/otel"
 )
 
 var podNamespace string
@@ -263,9 +265,16 @@ func (api *API) GetHandler() http.Handler {
 	return r
 }
 
-func (api *API) Serve(port int) {
+func (api *API) Serve(port int, openTracingEnabled bool) {
 	address := fmt.Sprintf(":%v", port)
 	api.logger.Info("server started", zap.Int("port", port))
-	err := http.ListenAndServe(address, api.GetHandler())
+
+	var handler http.Handler
+	if openTracingEnabled {
+		handler = &ochttp.Handler{Handler: api.GetHandler()}
+	} else {
+		handler = otel.GetHandlerWithOTEL(api.GetHandler(), "fission-controller", otel.UrlsToIgnore("/healthz"))
+	}
+	err := http.ListenAndServe(address, handler)
 	api.logger.Fatal("done listening", zap.Error(err))
 }

pkg/controller/api_test.go

@@ -374,7 +374,7 @@ func TestMain(m *testing.M) {
 
 	panicIf(err)
 
-	go Start(logger, 8888, true)
+	go Start(logger, 8888, true, true)
 
 	time.Sleep(5 * time.Second)
 

pkg/controller/controller.go

@@ -24,7 +24,7 @@ import (
 	"github.com/fission/fission/pkg/crd"
 )
 
-func Start(logger *zap.Logger, port int, unitTestFlag bool) {
+func Start(logger *zap.Logger, port int, unitTestFlag bool, openTracingEnabled bool) {
 	cLogger := logger.Named("controller")
 
 	fc, kc, apiExtClient, _, err := crd.MakeFissionClient()
@@ -53,5 +53,5 @@ func Start(logger *zap.Logger, port int, unitTestFlag bool) {
 	if err != nil {
 		cLogger.Fatal("failed to start controller", zap.Error(err))
 	}
-	api.Serve(port)
+	api.Serve(port, openTracingEnabled)
 }