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>

charts/fission-all/templates/fluentbit.yaml

@@ -117,6 +117,8 @@ spec:
                 fieldRef:
                   apiVersion: v1
                   fieldPath: spec.nodeName
+            - name: OPENTRACING_ENABLED
+              value: {{ .Values.openTracing.enabled | default false | quote }}
           command: ["/fission-bundle"]
           args: ["--logger"]
           volumeMounts:
@@ -158,6 +160,8 @@ spec:
                   key: password
             - name: LOG_PATH
               value: /var/log/fission/*.log
+            - name: OPENTRACING_ENABLED
+              value: {{ .Values.openTracing.enabled | default false | quote }}
 {{- if .Values.logger.enableSecurityContext }}
           securityContext:
             privileged: true