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/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)
 }