feat: OpenTelemetry module integration (#9062)

* OpenTelemetry module integration

* e2e test

* e2e test fix

* default OpentelemetryConfig

* e2e values

* mount otel module for otel test only

* propagate IS_CHROOT

* propagate IS_CHROOT e2e test

* code doc

* comments

* golint

* opentelemetry doc

* zipkin

* zipkin

* typo

* update e2e test OpenTelemetry value

* use opentelemetry value

* revert merge conflict

* fix

* format

* review comments

* clean

internal/ingress/annotations/opentelemetry/main.go

@@ -0,0 +1,101 @@
+/*
+Copyright 2022 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package opentelemetry
+
+import (
+	networking "k8s.io/api/networking/v1"
+
+	"k8s.io/ingress-nginx/internal/ingress/annotations/parser"
+	"k8s.io/ingress-nginx/internal/ingress/resolver"
+)
+
+type opentelemetry struct {
+	r resolver.Resolver
+}
+
+// Config contains the configuration to be used in the Ingress
+type Config struct {
+	Enabled       bool   `json:"enabled"`
+	Set           bool   `json:"set"`
+	TrustEnabled  bool   `json:"trust-enabled"`
+	TrustSet      bool   `json:"trust-set"`
+	OperationName string `json:"operation-name"`
+}
+
+// Equal tests for equality between two Config types
+func (bd1 *Config) Equal(bd2 *Config) bool {
+
+	if bd1.Set != bd2.Set {
+		return false
+	}
+
+	if bd1.Enabled != bd2.Enabled {
+		return false
+	}
+
+	if bd1.TrustSet != bd2.TrustSet {
+		return false
+	}
+
+	if bd1.TrustEnabled != bd2.TrustEnabled {
+		return false
+	}
+
+	if bd1.OperationName != bd2.OperationName {
+		return false
+	}
+
+	return true
+}
+
+// NewParser creates a new serviceUpstream annotation parser
+func NewParser(r resolver.Resolver) parser.IngressAnnotation {
+	return opentelemetry{r}
+}
+
+// Parse parses the annotations to look for opentelemetry configurations
+func (c opentelemetry) Parse(ing *networking.Ingress) (interface{}, error) {
+	cfg := Config{}
+	enabled, err := parser.GetBoolAnnotation("enable-opentelemetry", ing)
+	if err != nil {
+		return &cfg, nil
+	}
+	cfg.Set = true
+	cfg.Enabled = enabled
+	if !enabled {
+		return &cfg, nil
+	}
+
+	trustEnabled, err := parser.GetBoolAnnotation("opentelemetry-trust-incoming-span", ing)
+	if err != nil {
+		operationName, err := parser.GetStringAnnotation("opentelemetry-operation-name", ing)
+		if err != nil {
+			return &cfg, nil
+		}
+		cfg.OperationName = operationName
+		return &cfg, nil
+	}
+
+	cfg.TrustSet = true
+	cfg.TrustEnabled = trustEnabled
+	operationName, err := parser.GetStringAnnotation("opentelemetry-operation-name", ing)
+	if err != nil {
+		return &cfg, nil
+	}
+	cfg.OperationName = operationName
+	return &cfg, nil
+}